Show Summary Details

Page of

PRINTED FROM OXFORD HANDBOOKS ONLINE ( © Oxford University Press, 2018. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Handbooks Online for personal use (for details see Privacy Policy and Legal Notice).

date: 24 February 2020

Future Research on Obsessive Compulsive and Spectrum Conditions

Abstract and Keywords

This chapter reviews comments raised by authors of 25 chapters of the Handbook of Obsessive Compulsive and Spectrum Disorders. Among the challenges raised are those within the areas of diagnosis and features of the several OC spectrum conditions, including revisions to the diagnostic nomenclature for DSM-V under consideration, especially with regard to the possible addition of hoarding disorder to distinguish this more clearly from OCD. Research on clinical versus nonclinical samples, and controversies regarding possible subtypes of OCD and of some of its spectrum conditions like BDD and hoarding, are examined. Relationships among OCD and the spectrum conditions are examined with attention to the general lack of information about this issue. Several authors in the handbook comment on personality features and their association with outcomes following treatment, with a general consensus that assessing features rather than disorders will be most useful. The impact of culture on expression of OC spectrum conditions is clearly under-studied. Causes and mechanisms underlying OCD and spectrum conditions are examined, including neurological and genetic underpinnings, information processing, beliefs and cognitive models, as well as social and familial factors. Concerns about assessment are raised with regard to OCD and its expression in older adults, in hoarding and in BDD, and the impact of culture on assessment. With regard to treatment, chapters focus on research needs concerning mechanisms of action and predictors of change, and the need to improve treatments to enhance their effects. Improvement of outcomes in a variety of areas (e.g., hoarding, children, culturally sensitive treatments) is noted, including outcomes for medications and combined CBT plus medication regimens. Special issues are raised with regard to BDD, tic disorders, and trichotillomania.

Keywords: obsessive compulsive disorder, OCD, OC spectrum, research, body dysmorphic disorder, trichotillomania, tics, hoarding

The chapters in this book cover the current knowledge about obsessive compulsive disorder (OCD) and its spectrum conditions. Although we certainly know a great deal more about these problems than we did many years ago, it is also clear that we still know too little. This is most evident in the research on interventions, especially for the obsessive compulsive (OC) spectrum conditions, where our knowledge depends on our understanding of the phenomenology, psychopathology, and biology of these problems, as well as our ability to synthesize this information into sensible theories that guide treatments. Below, we review chapter authors’ highlights of the inadequacies and remaining challenges in understanding these disorders, with the goal of pointing toward future research that will help answer the many remaining questions in the field. Our review is organized around the following topics: diagnosis and epidemiology, causes and mechanisms, assessment concerns, treatment, and special concerns. We hope that this discussion will point the way to important collaborative research efforts (p. 522) to move the study of OCD and OC spectrum conditions forward.

Diagnosis and Phenomenology

A number of challenges with regard to diagnosis and phenomenology of OC spectrum conditions are apparent from the research summaries in this book. Below, we describe concerns raised in several areas, including: revisions to diagnostic systems along dimensional versus categorical lines; the value of nonclinical samples in studying the features of OC spectrum conditions; the validity of subtyping of OCD, and possibly its related disorders; the relationship among OC spectrum conditions; and personality features and cultural factors, especially as these inform our understanding of the etiology of these disorders. Our goal is not to answer these concerns, but to deliberately raise questions and point to areas needing further study.

Revising the Diagnostic System

Calamari, Chik, Pontarelli and DeJong (Chapter 2) point to the evident need to elucidate the phenomenology of OCD before attempting to revise the diagnostic system toward the 5th edition of the Diagnostic and Statistical Manual (DSM-V), on which the American Psychiatric Association has begun to work. At the present time in 2010, the DSM 5 work group is recommending that OCD be included under a grouping of “Anxiety and Obsessive-Compulsive Spectrum Disorders,” responding in part to some suggestions that OCD may be less clearly an anxiety disorder than has been assumed in the past. The work group is also considering adding avoidance to define obsessions, as well as indicating the need to distinguish OCD from hoarding disorder and from skin-picking disorder (if these are added to the DSM as separate conditions).

A major concern here is the validity and utility of identifying OCD subtypes. While research on subtypes has advanced, it is not yet clear that distinguishing among those that most clinicians and researchers agree are common (such as washing, checking, ordering, repeating) will prove helpful in advancing the field toward effective interventions. Among the concerns here is whether our natural human tendency to collect symptoms into categories, rather than dimensions, best serves the understanding of the meaning and associations among these features. However, the separation of hoarding symptoms into an independent diagnostic category separate from OCD, now in the works for DSM-V, is clearly an advance, given the substantial differences between the two in symptom patterns as well as a variety of behavioral, emotional, cognitive, and biological features (see Frost & Rasmussen, Chapter 4).

Another major problem that may be impeding progress is a tendency across OC spectrum conditions to develop diagnostic criteria for children as scaled-down interpolations of adult diagnoses. Because most information is based on data gathered from adults, the field often falls short in understanding the child and adolescent manifestations of OCD and of OC spectrum conditions, such as body dysmorphic disorder (BDD) and hoarding. This is partly because it is easier to conduct research on adults—participant access, IRB approval, and informed consent is more difficult with legal minors—and we often lack the longitudinal studies that follow children well into adulthood to determine how symptoms evolve over time. In a related vein, Ricketts, Woods, Antinoro and Franklin (Chapter 5) raise the question of whether age of onset might predict the type and/or severity of the longitudinal course of OCD symptoms. As Storch and colleagues (Chapter 25) suggest, it may be time to revise the OCD diagnostic scheme by integrating data about children.

Clinical Versus Nonclinical Samples

The debate about whether findings from nonclinical research can be generalized to the understanding of clinical phenomena continues to this day, but in fact, considerable information has accumulated in the past three decades from research on students and on those with subclinical levels of OCD. Calamari et al. (Chapter 2) point to the commonalities and the differences between clinical and nonclinical obsessions, as do Kelly and Phillips (Chapter 3) for delusional and nondelusional body dysmorphic disorder (BDD) obsessions and behaviors. In a similar vein, Ricketts et al. (Chapter 5) raise the question of whether nonclinical forms of tics, Tourette syndrome, and trichotillomania actually predict future onset of the full blown disorder, or instead are distinct and stable traits. Nonetheless, the potential benefits of conducting research into not-yet-clinical symptoms of any of these conditions seem substantial. This is perhaps well underscored by reliably reproduced findings that the precursors to obsessive thoughts, images, and impulses—“intrusions”—are actually very common among ordinary people (e.g., Rachman & de Silva, 1978; Salkovskis & Harrison, 1984), but such intrusions appear to require vulnerability factors to advance to clinical symptoms that spiral into a serious disorder (see Taylor, Abramowitz, McKay and Cuttler’s Chapter 12 in this volume). (p. 523) This observation has led to important theoretical advances that seem to benefit the field with regard to explaining symptom onset and expanding treatment options.


Virtually all of the authors in this volume have pointed out the clinical heterogeneity of OCD itself, as well as the heterogeneity within each of the spectrum disorders (see especially Calamari et al., Chapter 2, and Taylor, Abramowitz, McKay, and Cuttler, Chapter 12). Even the newest disorder, hoarding, might be subtyped into object hoarding versus animal hoarding, as well as hoarding with and without squalid conditions in the home (Frost & Rasmussen, Chapter 4). The challenge is to determine what falls inside and outside of the diagnostic category, even as we try to better understand the dimensions on which syndromes or disorders vary. As geneticists Samuels, Bienvenu, Planalp, and Grados (Chapter 6) suggest, the field needs clarity on phenotypes (clinical subtypes) to determine how they are genetically similar or different. Likewise, Mataix-Cols and van den Heuvel (Chapter 7) express concern that clinical heterogeneity makes it more difficult to interpret findings from neuroscience studies of OCD. Similar arguments can be made for examining other features, such as severity, comorbidity, cognitive processing, and so forth.

Within this discussion of subtypes, one challenge put forward by Cassin and Rector (Chapter 11) is to examine similarities and differences not only in how symptoms appear, but also in the functions they serve. This important distinction between appearance and function yielded an especially helpful understanding of OCD decades ago when it became clear that obsessions provoke discomfort, whereas compulsions are intended to reduce this discomfort (see Rachman & Hodgson, 1980; Foa, Steketee, & Milby, 1980). This understanding further clarified that rituals might take either a behavioral or mental form (e.g., undoing a bad image with a good image, or with a ritual behavior), and therefore effective behavioral treatment requires identifying not only the form but the function, to apply the appropriate corrective experience. Although as Cassin and Rector have noted, the behavioral model described more than 30 years ago by Rachman and Hodgson (1980) is not sufficient to account for the complexity and heterogeneity of OCD, it nonetheless provided an important window that advanced understanding and treatment of OCD. Perhaps novel ways of examining subtypes will result in new, and perhaps more meaningful, clusters that differ in responsiveness to different treatments (see also Dorfan & Woody, Chapter 13). This has begun to yield fruit in the case of hoarding. When separated from OCD, so that recruitment does not bias samples toward the presence of obsessions and compulsions, a better understanding of the features and functions of difficulty discarding and clutter begin to emerge (see Frost & Rasmussen, Chapter 4, and Purdon, Chapter 14). Working from the other direction, responses to treatment may also guide our understanding of the phenotype. So, for example, a better understanding of the clinical response to neurosurgery might guide the understanding of OCD symptoms (McLaughlin & Greenberg, Chapter 10).

Relationships among OC Spectrum Disorders

It is not at all clear that the somewhat disparate conditions known as OC spectrum disorders share an underlying pathology. This issue has been hotly debated (see Abramowitz & Houts, 2005) and it will not likely be resolved anytime soon. Ricketts et al. (Chapter 5) raise the question of whether efforts to distinguish tics from Tourette syndrome from trichotillomania and from OCD will help clarify the etiology of these conditions. Nor is it clear that the functional impairment associated with the first three of these conditions can be separated from the functional impairment from their non-OC spectrum co-occurring conditions. Further, would doing so usefully inform efforts to improve overall functioning? A similar concern arises in BDD, the recognizable obsessive and compulsive symptoms of which seem a more severe and highly specialized form of OCD; in surface symptoms, BDD seems more similar to OCD than do tic disorders and trichotillomania. However, both BDD and OCD are highly comorbid with other anxiety and mood disorders, raising the question of whether it is equally important to examine the similarities and differences of these conditions with social anxiety, panic, and depression, as well as with each other (see comments by Kelly and Phillips in Chapter 3). In the same vein, hoarding bears similarities to impulse control disorders and addictive conditions such as gambling and compulsive buying, but is also highly comorbid with mood and anxiety disorders (social phobia, generalized anxiety disorder; see Frost & Rasmussen, Chapter 4).

Studying the shared features (phenomenology) among like disorders may be more important for understanding phenotype than examining comorbid (p. 524) conditions that could be simply a consequence or side effect of the problem (e.g., excessive clutter impairs functioning, which gives rise to depressed mood). However, might an underlying problem give rise to both conditions in either case? For example, BDD and hoarding share substantial social phobia comorbidity; might all three arise from some basic source of low self-esteem, leading to feelings of social inadequacy and isolation? On the other hand, both BDD and hoarding also share unusually high rates of major depression (although suicidal ideation and intent seem to characterize BDD more than hoarding). Is depression merely a side effect of the debilitation that stems from both conditions (and therefore less interesting as an explanatory factor), or is it a central feature and, again, somehow a driving force for the symptoms themselves? For example, are depressed people more likely to develop hoarding and/or BDD? Clearly, understanding both the central and secondary features of these conditions could hold clues to explaining their etiology.


Just as concerns about categorical classification versus dimensions arises for OC spectrum disorders, so it does for the associated personality disorders detailed in DSM-III and DSM-IV. Pinto and Eisen (Chapter 10) suggest that research on obsessive compulsive personality disorder (OCPD), in particular, underlies much of our understanding of OCD, beset as personality diagnoses are by serious problems with validity, reliability, and excessive overlap between diagnoses. They suggest, and many agree, that research using dimensional approaches to personality seems more promising, especially in teasing apart the complex relationship between OCD and OCPD. Interestingly, for example, it seems likely that the revised DSM-V will at least remove the hoarding criteria from OCPD, given its low loading (dimensionally) with other features of OCPD, which are more strongly related to each other. Specifically, Pinto and Eisen recommend assessing people with OCD for the dimensional strength of individual OCPD traits, rather than for the presence or absence of an overall OCPD diagnosis. This suggestion follows recent studies of predictors of therapy outcome, in which individual personality disorder categories are rarely prevalent enough to study, and often do not predict outcome even in large samples (e.g., Steketee & Shapiro, 1995; Steketee, Chambless & Tran, 2001). In contrast, researchers are more likely to study whether the number of personality disorders or traits are predictive. Similarly, longitudinal studies may examine whether certain traits (rather than full blown OCPD) predict onset, course, or treatment response, as well as whether certain traits change in response to successful treatment. Pinto and Eisen also suggest that biological processes (neurophysiological, biochemical, neuropsychological) are likely to underlie personality differences between people with OCD, and that these basic features may help us find endophenotypes that could mediate the relationship between genes and behavioral manifestations/phenotypes (Gottesman & Gould, 2003).


Considerable research points to similarities in the expression of OCD symptoms across cultures, although the source of the obsessive content can be idiosyncratic to the specific culture (e.g., de Silva, 2006). Surprisingly little research has been done on OC spectrum conditions in this regard, perhaps simply because they are somewhat less prevalent than OCD. Kelly and Phillips (Chapter 3) raise the question of how BDD might manifest in different cultural contexts. Similarly, Nedeljkovic, Moulding, Foroughi, and Kyrios (Chapter 26) call for more research to understand the similarities and differences in OCD presentation across cultures—for example, to determine whether various subtypes of OCD are similar in structure and frequency across cultures. Interestingly, Ricketts et al. (Chapter 5) wonder whether cultural differences in the phenomenology of tics, Tourette’s Syndrome, and trichotillomania might increase our understanding of those conditions. Their interest lies not merely in understanding the expression of these disorders and the effects of treatment, but also in understanding the mechanisms of action/underlying processes. This seems a particularly promising avenue of study, to take the next step whenever possible beyond mere descriptive studies to examining mechanisms, a natural segue into our next section.

Causes and Mechanisms

Just as the previous paragraph pointed to the importance of understanding the mechanisms of action behind the symptoms described in our OC spectrum conditions, here we examine possible ways to do so. Below are comments and discussions of possible neurological and genetic underpinnings, research on information processing, and potential cognitive factors that might influence onset and maintenance of OCD and some spectrum disorders.

(p. 525) Neurological and Genetic Underpinnings

An important goal of understanding and modeling these disorders is to improve treatment efforts and outcomes, and possibly even prevent the development of the disorder (see Kelly and Phillips discussion of BDD in Chapter 3). Samuels et al. (Chapter 6) point to some of the major challenges of genetics research with regard to the possibility of gene–gene and gene–environmental interactions, and the involvement of multiple genes and regions to map different subtypes with different genetic inheritance patterns. The challenge here is the need to identify different clinical subtypes or phenotypes. As they note, developments in molecular and statistical genetics will, hopefully, enable researchers to examine the entire genome for thousands of participants, looking for much narrower linkage areas using newer SNP markers. It is clear that very large samples are needed to boost power to detect small regions with more subtle effects, and that the statistical approaches must be sophisticated to do this work across multiple sites. Such research has been undertaken by large groups of genetics researchers, supported by the International OC Foundation (IOCDF, and by the federal government. New developments in genetic research (such as epigenetics and genome sequencing) are being applied to this topic and seem likely to bear fruit.

In another biological arena, Mataix-Cols and van den Heuvel (Chapter 7) point out that the widely accepted neurobiological model of OCD involving the fronto-striato-thalamic circuits may be an oversimplification of the true situation, given the extensive heterogeneity of OCD. As noted earlier, the overlap of OCD with various anxiety and mood disorders will require a neurobiological model that includes an understanding of these conditions and how they might interface with OCD and OC spectrum conditions. This will require research that compares OCD with other anxiety and mood disorders, either directly within single studies or by using identical imaging protocols in different studies (cross-study comparisons). According to these authors, the current model proposes qualitative differences in the brains of those with and without clinical OCD. One challenge, however, is that some brain regions identified in recent OCD studies are also involved in “normal” emotional responses of healthy brains, suggesting differences in quantity rather than quality. This seems to support neuroimaging research on subclinical OCD, and also favors a dimensional diagnostic approach over a categorical one.

Mataix-Cols and van den Heuvel (Chapter 7) further note that recent studies implicate additional brain regions that were not included in the early studies on which the “standard model” (fronto-striato-thalamic circuits) was based. These include the temporal and parietal cortices, the cerebellum and paralimbic regions. They suggest the importance of examining complex cortical/limbic interactions (see Chapter 7 for more details about suggested areas of study), and of doing so using longitudinal studies that include untreated control groups. For example, longitudinal studies might follow children with and without OCD into adulthood, allowing study of the natural history of OCD using multimodel designs that combine imaging studies with chemical assays, or with genetic research. They propose that a particularly fruitful strategy will be to examine the overlapping and distinct neural correlates of OCD, of symptom dimensions/subtypes, and of related disorders, using well-validated and comparable paradigms. The goal of this work is to gain insight into the interactions between a wider purview of specific circuits, in order to better understand the clinical overlap and differentiation among OC spectrum disorders. This is challenging research because it requires combining research groups with disparate areas of expertise, retention of large patient samples over time, and a multimodal, multidisciplinary, longitudinal approach. Certainly it will benefit from a planned program of research that can rarely be accomplished by individual investigators.

Following upon this ambitious suggestion is McLaughlin and Greenberg’s argument for a better understanding of anatomical, pharmacological, and behavioral underpinnings, especially the mediating mechanisms, in order to improve neurosurgery for OCD (Chapter 10). They note the need to verify empirically the clinical impression of a number of researchers that at least some patients who are unresponsive to rigorous behavioral treatment do, in fact, benefit from neurosurgery. Identifying what distinguishes these individuals is an especially important part of the discovery effort, with regard to determining who qualifies for this more radical treatment when all else fails. These authors also propose that a registry be maintained of all patients who have received neurosurgery for psychiatric conditions, including both surgical and clinical data. This seems likely to help identify the characteristics of the most appropriate candidates for future surgeries (Goodman & Insel, 2009).

(p. 526) Information Processing

Radomsky and Alcolado (Chapter 8) argue that the clinical presentation of OCD clearly indicates a difference from the general population in information processing, but that many studies have lacked ecological validity to demonstrate this. One problem is that information-processing problems reduce or disappear, following successful treatment for the symptoms of OCD, making it difficult to determine whether these problems cause OCD, are a parallel problem with the same cause as OCD, or result from OCD. To adequately study information processing, the measures must be highly clinically relevant (ecologically valid) in order to facilitate an understanding of the nature, course, and interrelationship of attentional and memory biases and executive functioning in OCD. For example, studies can examine processing in vivo during real-life threatening and nonthreatening situations.

One clear need Radomsky and Alcolado identify is for measures or assessment strategies that are clinically relevant. This improved assessment is a prerequisite to the better understanding of the nature of the attentional biases, memory biases, and difficulties in executive functioning in OCD, both in their development courses and their interrelationships. This gap is highlighted by the as yet unexplained finding that information processing problems lessen or disappear when treatment for OCD is successful. Do information-processing problems lead to OCD, or does OCD lead to information-processing problems? In general, it remains to be seen what contributions cognitive science can make to understanding and treating OCD, but the gap between laboratory assessments in controlled conditions, and the fluid real-world settings in which OCD manifests, remains a barrier at this time. In this regard, it is unclear what contributions cognitive science can make to understanding and treating OCD, and much remains to be done in research on information processing.

In a similar vein, Radomsky and Alcolado point out that it is still not clear how best to address OC spectrum clients’ information-processing problems. For example, many clients who hoard show neurocognitive deficits in attention, memory, and executive functioning (e.g., organizing information). Similarly, Taylor et al. (Chapter 12) point to recent studies of the emotional components of abstract decision making (for example, in doing math problems) that may be part of the information-processing challenges faced by people with OCD and related disorders. However, as yet, we know little about what behavioral, cognitive remediational, and/or pharmacological approaches might help improve these skills (see Grisham, Norberg, and Certoma, Chapter 22). Training in skills for organizing and managing attention problems (akin to those used for adults with attention deficit hyperactivity disorder) have been applied as part of a multicomponent cognitive and behavioral treatment (Steketee et al., 2010), but have not been assessed separately to determine their specific impact on cognitive processing problems. Dismantling designs that examine the specific effects of treatment components may be helpful in this regard, but it seems likely that additional targeted treatments of information processing may be needed for hoarding, and perhaps for other OC spectrum conditions. For example, Amir and colleagues (Najmi, S., & Amir, N., 2010) have shown benefits of information-processing training for people with subclinical OCD. Further development of these or similar cognitive training methods may prove helpful in resolving this aspect of OC spectrum disorders.

Pertinent to this topic, another area of interest is to determine the effects of neurosurgeries on neurocognitive processing, as well as on OCD symptoms. However, this goal must be embedded in the larger question of whether the risks associated with various types of neurosurgeries are acceptable in comparison to the benefits in OCD symptoms and in quality of life (see McLaughlin & Greenberg, Chapter 10).


Considerable research activity in recent decades has focused on the types of beliefs evident in OCD patients, and the role of such beliefs in the development and maintenance of OCD symptoms. As Taylor and colleagues point out in Chapter 12, it is possible that the subset of beliefs adopted by a research working group (OCCWG, 1997) may not have included all of the relevant belief patterns. For example, many OCD patients report having “not just right” experiences, in which they have difficulty ending an activity because of a feeling that the action has not been completed fully or adequately. As these authors note, this uncomfortable sensation leads to rituals aimed at reducing internal tension, rather than avoiding any specific feared outcomes. Likewise, the sympathetic magic involving disgust reactions may account for contamination fears better than trait anxiety about contamination (e.g., Moretz & McKay, 2008). Inclusion of not just right experiences and disgust in a more comprehensive (p. 527) model of obsessive compulsive phenomena seems an important next step.

Cognitive models of OC spectrum disorders (e.g., BDD, hoarding) remain inadequately tested at this time. In general, these have been modeled after cognitive theories of OCD, and thus are likely to suffer from some of the same limitations being discovered in those models; for example, incomplete articulation of the types, sources, and impact of various beliefs. As Taylor and colleagues propose (Chapter 12), the models of OCD and of OC spectrum disorders also require more integration and fine-tuning to account for why individuals develop one rather than another condition, why some disorders are more likely to be comorbid than others, and why the presence of one disorder increases risk for another in the future. Further, cognitive models need to account for developmental differences across the lifespan. These include differences in cognitive development, especially from childhood through adolescence and into adulthood, as well as changes in salient content of obsessions. For example, what matters to a child in school can be quite different from what matters to an elderly person in retirement. An important unanswered question is whether cognitive development over the lifespan shapes the form and content of dysfunctional OC beliefs.

Further, as Taylor and colleagues indicate in Chapter 12, such models have not yet been integrated with regard to findings from information processing research, neuroscience, and genetics, especially with regard to identifying subtypes of OCD for which various cognitive models, or parts of models, have more or less salience. Unfortunately, these models were developed largely independently of (and therefore uninformed by) neurobiological research. This serious omission in the literature leaves questions about whether certain dysfunctional beliefs are based on specific neurobiological correlates, or particular patterns of information-processing problems.

In addition, current cognitive models are undeveloped with regard to accounting for cross-cultural differences in both beliefs and the focus of concerns in spectrum conditions such as BDD and hoarding. As Nedeljkovic et al. suggest in Chapter 26, elucidation of cultural factors and how these affect symptomatic expression may require substantial revision of the cognitive-behavioral therapy (CBT) models of OCD and spectrum conditions. For example, Cassin and Rector (Chapter 11) ask, might early traumas and stressful events have different impacts on beliefs and manifestations of OC spectrum conditions across cultures?

Social and Family Factors

Also under-studied are the social and familial factors that affect the development and expression of OCD and OC spectrum conditions. As Renshaw, Caska, Rodriues, and Blais note in Chapter 9, people with OCD who are treated with hostility from family members experience a well-demonstrated negative impact on treatment outcomes, leading to the clear conclusion that hostility in the living environment is problematic and should be corrected whenever possible. However, many questions remain under-studied. For example, is hostility an important contributing factor to the anxiety and often negative self-esteem that generates OCD, as well as BDD and hoarding? Given that nonhostile criticism did not confer the same serious negative treatment outcomes (e.g., Chambless & Steketee, 1999), might it actually be beneficial as a motivator (see Renshaw et al., Chapter 9)? Further, Purdon (Chapter 14) raises questions about possible reciprocal influences of OCD symptoms, family accommodation, and expressed emotion (criticism, hostility, emotional overinvolvement). For example, do excessive overinvolvement and/or family accommodation produce more or less tolerance among relatives to OCD symptoms? What impact does this have on symptoms of OCD or OC spectrum disorders? Nedeljkovic, Moulding, Foroughi and Kyrios (Chapter 26) also raise the question of whether cultural differences, in the definition and experience of unwanted intrusions, affect how others respond to these symptoms, as well as their effect on functioning.

As reported in Chapter 4, research on hoarding suggests that many people who hoard are unmarried and live alone. Likewise, similar research on OCD also indicates less effective social functioning (Chapter 2), and these conditions, as well as BDD, are associated with considerable social anxiety (Chapters 24). What is not yet clear is whether social discomfort and poor social functioning share similar causal factors with OC spectrum conditions, or whether both sets of symptoms are reciprocally influential (e.g., OC spectrum conditions lead to social dysfunction, or social discomfort exacerbates OC spectrum symptoms). Clearly, much work remains to be done in the family and social arena to better understand the possible effects on symptoms and on treatment outcomes.


Much has been accomplished in developing and testing assessment instruments that capture well the symptoms and related functioning problems (p. 528) associated with OCD, and with the several spectrum conditions described in this volume. Nonetheless, a number of challenges remain. With regard to OCD, symptom patterns are well studied, and several useful instruments are available for identifying these from multiple perspectives (patient, independent assessor, clinician). Several remaining concerns are articulated by Dorfan and Woody (Chapter 13). It is not clear whether beliefs can be accurately measured at different levels of specificity; for example, can interpretations/appraisals be distinguished from beliefs, as a number of researchers have attempted to do? Assessments of information processing deficits have been used in research settings, but are these useful or feasible in clinical practice? Depression is closely entwined with serious OCD symptoms, and measures of OCD severity are often not independent of this negative mood; perhaps it is neither possible nor fruitful to attempt to separate these conditions.

Carmin, Calamari, and Ownby (Chapter 24) raise several concerns about the psychometrics of standard OCD symptom measures when used with older adults. They suggest a need to distinguish OCD and other OC spectrum disorders from other anxiety and mood disorders, in order to reliably diagnose confusing comorbid conditions in this population. For example, in the elderly, it seems essential to develop methods that reliably distinguish geriatric psychiatric disorders from the emotional sequelae of late-life cognitive and physical decline, in order to provide better targeted interventions. These authors point to a need to assess OCD in elders living in retirement and nursing facilities, especially given that higher-care facilities will have higher incidences of significant mental and physical impairment problems and comorbid psychiatric conditions. For example, accurate assessments that distinguish disorders will facilitate collection of more accurate epidemiological data about the prevalence of hoarding among older people.

With regard to the spectrum condition of hoarding, a significant problem with the first studies of this problem, and even now, with some research, is the frequent use of OCD samples and OCD assessment measures to study hoarding. These assessments were not developed to measure the severity of hoarding, and thus lack essential validity and may seriously overestimate hoarding symptoms (see Frost and Rasmussen’s discussion in Chapter 4). However, recently developed, well-validated hoarding measures are now available in self-report forms (e.g., Frost et al., 2004), observational instruments (Frost et al., 2008), and interview measures (Tolin, Frost, & Steketee, 2010). Other OC spectrum conditions also have reliable and valid measures of symptoms and related functioning aspects, as indicated in the relevant chapters on these disorders. However, with regard to BDD, Kelly and Phillips (Chapter 3) raise concerns about why BDD is frequently missed in clinical settings; effective methods for screening for conditions that patients often hide on initial clinic presentation (e.g., BDD, hoarding) seems an important goal for research and clinical practice.

How culture affects patients’ responses to measures of OCD and OC spectrum disorders, and how these conditions can be assessed more reliably across cultures, remains a concern in the assessment literature (see Nedeljkovic et al., Chapter 26). An additional need raised by McLaughlin and Greenberg in Chapter 10 is for better ways to assess the clinical effectiveness of neurosurgeries for OCD patients who are not responsive to other treatments. Such measures may need to go beyond mere symptom severity to detecting improvements in functioning, social spheres, and general quality of life.


Mechanisms of Action and Predictors of the Therapeutic Change Process

An important goal of treatment research is to shed light on how and why the therapy produces (or does not produce) the desired benefits. Cassin and Rector (Chapter 11) express concern that to date, there is insufficient study of the mechanisms of change in behavioral treatments for OCD (exposure and response prevention, or ERP), including factors that interfere with successful habituation and extinction of obsessive fears. With regard to cognitive therapy (CT) for OCD, Whittal and Robichaud (Chapter 18) concur, noting that because this is a relatively new therapy method, more studies of predictors of treatment are needed to elucidate how it works. Apropos of both suggestions, Abramowitz and colleagues (Chapter 17) recommend that specialized symptoms of OCD, such as “not just right experiences,” need more study with regard to their response to ERP; this can be extended to CT methods, as well. In a very similar vein, Grisham et al. (Chapter 22) call for investigation of possible subtypes of hoarding (e.g., those with or without comorbid OCD) that might respond differentially to CBT methods, and might benefit from combining specialized hoarding methods with standard CBT methods for OCD symptoms.

(p. 529) Improving Treatments to Enhance their Effects

Both CBT and serotonergic medications for OCD have produced very positive outcomes, as articulated in Chapters 15, 17, and 18. However, how to modify therapy methods for those who do not respond well to standard treatments remains an issue. Abramowitz et al. raise this issue with regard to ERP in Chapter 17. Among the suggested options is modification of the existing therapy methods—for example, by extending the treatment period, or expanding the purview and methods within the therapy, to address comorbid conditions (see Whittal and Robichaud, Chapter 18). A further suggested option is to add psychosocial methods, such as family treatment (see Purdon, Chapter 14). In this regard Renshaw, Caska, Rodrigues and Blais (Chapter 9) encourage research that will clarify best practices for incorporating family members into treatment—for example, identifying the characteristics of family members and clients who are likely to benefit from such treatment, and best methods for conducting the family treatment.

Additional strategies focus on additive therapies such as D-cycloserine (DCS), which might be used to augment ERP methods and possibly improve treatment outcomes for subgroups such as OCD patients with poor insight (see Chapter 17 by Abramowitz et al. on adults, and Chapter 25 by Storch et al. on children). Tolin (Chapter 19) raises questions about whether non-serotonergic medications (SRIs) such as benzodiazepines, atypical antipsychotics, or cognitive enhancers or other neuroplasticity compounds, might improve the effects of CBT. He also suggests that understanding how such additive medications have their impact is an important element for understanding treatment mechanisms better, and for improving outcomes.

Some authors provide specific suggestions for further research on improving treatments for OC spectrum conditions. For example, Grisham et al. (Chapter 22) recommend comparing intensive treatment vs. weekly outpatient therapy for hoarding, in order to better study how hoarding patients respond when therapy intensity is varied. They also suggest the need to test the specific benefits of motivational interviewing in improving outcomes for hoarding treatment (see Steketee & Frost’s treatment manual, 2007). Since most medication treatments for hoarding have been studied only retrospectively, an important remaining need is to determine prospectively whether a range of medications will provide significant benefit. Storch and colleagues (Chapter 25) indicate that researchers need to study child treatments to better understand which treatments, and which augmentation strategies, are most effective, in which combinations, for whom. This work has begun for children, and also for adults with OCD and OC spectrum conditions, but will require considerable additional development over time. Finally, in Chapter 26, Nedeljkovic et al. are concerned that elucidation of cultural factors are likely to require revision of CBT models of OCD that will need to be integrated (not merely added to) treatment protocols. For example, van Noppen and colleagues are currently developing and testing a family treatment intervention for Latino OCD patients and their families, by modifying both the content and therapy procedures to fit cultural expectations (personal communication, October, 2010).

Medication and CBT + Medication Regimens

With regard to medications for OCD, Dougherty, Rauch, and Jenike (Chapter 15) point to the need for research that tailors individual medication regimens to individual people. This entails not only determining the most effective monotherapies for specific individuals, but also when augmentation would be helpful. Tolin (Chapter 19) raises the question of whether serotonergic medications are effective for CBT nonresponders and partial responders. He expands on Dougherty et al.’s goals to tailor treatment to individual patient characteristics (such as severity of illness, previous treatment history, comorbidity) with regard not only to monotherapies (e.g., CBT or medications alone) but also to combined therapies (CBT plus medications). These treatments must also be examined for costs and benefits to better understand the overall impact on patients and their families. For example, both Tolin (Chapter 19) and Grisham (Chapter 22) raise questions about whether under-studied subtypes such as hoarding will benefit more from combined treatments, rather than monotherapies.

Complementary and Alternative Treatments

Muroff, Ross, and Rothfarb’s Chapter 20 on complementary and alternative treatments notes the very serious methodological problems in much of the published research on these methods. These include small samples that provide very limited power, the lack of comparison groups, overreliance on self-report assessments without additional perspectives, inconsistency in using intent-to-treat (p. 530) versus completers-only analyses, and higher attrition rates for studies of OCD than for those of other anxiety disorders. Clearly, more rigorous studies of these interesting methods are needed to determine which complementary and alternative treatments are most effective and for whom, but in some cases, the personalized therapy methods may require research methodologies that do not fit the randomized clinical trial (RCT) model well. Among the substantive questions these authors raise about alternative methods is whether they may be effective for dealing with certain physical problems exacerbated by the mental health symptoms, and also whether there is a somatic subtype of OCD that would benefit especially from such interventions.


Concerns about dissemination of therapies for OCD and spectrum conditions are also raised in this volume. For example, might current research on healthcare utilization be helpful in informing the field about how best to disseminate effective treatment strategies, so they could become widely available in clinical practice settings and readily utilized by patient groups (see Ricketts et al., Chapter 5)? Greenberg, Chosak, Fang and Wilhelm (Chapter 21) raise concerns about how to disseminate treatments for BDD, because they are relatively new and not widely known. Similar needs are evident for making available newly developed CBT methods for hoarding. This problem of dissemination is not small, but in recent years the availability and interest of the media makes it possible to alert the public to opportunities that create demand with the mental health profession. As public demand increases, it become essential to study the most effective ways of moving treatments from sophisticated research settings into community settings. Franklin, Antinoro, Ricketts, and Woods (Chapter 23) suggest studying a “train the trainers” model to move treatments more rapidly to patient populations in need.

Special Issues

A variety of special issues for particular disorders are raised in the chapters in this book, mainly concerned with BDD and trichotillomania and tic disorders. These are discussed below.

Body Dysmorphic Disorder

Chapters 3 (Kelly & Phillips) and 21 (Greenberg et al.) on BDD point to several specialized concerns about this problem and those that suffer from it. For example, it is clear that researchers simply do not know enough about BDD from a longitudinal perspective, with only one prospective study identified to date. Nor are its neurobiological bases and risk factors, or cultural features, clear at this stage of the research. These authors also note concerns about possible differences between delusional and nondelusional forms of BDD, especially with regard to the need for treatments that adequately resolve convictions about body problems that are not evident to others. In particular, Greenberg and colleagues describe a clear need for research on prevention and early intervention for BDD during childhood, and especially adolescence, when concerns about appearance are common and can become ingrained in the form of mistaken and delusional beliefs that affect adult lives. The need for comprehensive intervention efforts is also evident given the complex combination of biological, psychological, and socio-environmental factors that affect the onset, course, and treatment for this condition. As the OC spectrum condition most associated with suicidality and physical damage, BDD may require specialized attention from researchers in order to manage the substantial risks associated with this condition if left untreated.

Trichotillomania and Tic Disorders

Another condition that poses special challenges for basic research into its neurobiological and neuroanatomical pathways is trichotillomania (Franklin et al., Chapter 23). Needed are studies of etiological and maintaining variables, such as emotional states, cognitive events, and physical sensations, such as a sense of inner pressure and “not just right” feelings that have also been identified for OCD (e.g., Ghisi, Chiri, Marchetti, Sanavio, & Sica, 2010). These symptoms may be associated with escaping or avoiding unpleasant emotions or thoughts. Another concerns raised in the discussion of these disorders is whether nonclinical or subclinical forms of tics and trichotillomania predict future onset, or instead are distinct and stable conditions (see Ricketts et al., Chapter 5). Further, as for other OC spectrum conditions, it is not clear whether there are distinct subtypes of these problems with differing severity (e.g., automatic versus focused hair pulling) that will shed light on possible differences in etiology, maintenance, and treatment outcomes. Another problem (also raised by Carmin et al. for OCD in elderly patients) is the difficulty in distinguishing functional impairment due to tics and trichotillomania from functional impairment due to comorbid conditions. As for other conditions, Ricketts et al. question whether (p. 531) there are cultural differences in the expression of these conditions, which might increase understanding as well as suggest strategies for treatment. Finally, Franklin et al. (Chapter 23) point to the need for more research on medications for tics and trichotillomania; while these conditions tend to be treated like OCD because of the repetitive behavior, they do not appear to respond well to medication protocols designed for OCD. Thus, more work is clearly needed on differential treatment(s), because at present, clinicians do not have access to an integrated, well-studied treatment protocol such as is available for OCD, BDD, hoarding, and other conditions. As Franklin et al. note, this problem might benefit greatly from a public advocacy campaign among peers and providers to alert the public and research funders to this problem.

Concluding Comments

Clearly, much research remains to be done on OCD and the several conditions we have come to call OC spectrum disorders. Not least among these is actually establishing the relationship and differences between these disorders. It is our hope that this volume assists the reader in better understanding the conditions detailed here with regard to their phenomenology, biological and psychosocial features, their assessment, and interventions. Of course, our most important goal is to understand each of these problems with such clarity that effective treatments can be identified that alleviate the suffering of the hundreds of thousands of people who have these problems around the world.


Abramowitz, J. S., & Houts, A. C., Eds. (2005). Concepts and controversies in obsessive-compulsive disorder. NY: Springer.Find this resource:

Chambless, D. L., & Steketee, G. (1999). Expressed emotion and behavior therapy outcome: A prospective study with obsessive compulsive and agoraphobic outpatients. Journal of Consulting and Clinical Psychology, 67, 658–665.Find this resource:

de Silva, P. (2006). Culture and obsessive-compulsive disorder. Psychiatry, 5, 402–405.Find this resource:

Foa, E. B., Steketee, G., & Milby, J. (1980). Differential effects of exposure and response prevention in obsessive-compulsive washers. Journal of Consulting and Clinical Psychology, 48, 71–79.Find this resource:

Frost, R. O., Steketee, G., & Grisham, J. (2004). Measurement of compulsive hoarding: Saving Inventory-Revised. Behaviour Research and Therapy, 42, 1163–1182.Find this resource:

Frost, R. O., Steketee, G., Tolin, D. F., & Renaud, S. (2008). Development and validation of the Clutter Image Rating. Journal of Personality and Behavioral Assessment. 30, 193–203.Find this resource:

Ghisi, M., Chiri, L. R., Marchetti, I., Sanavio, E., & Sica, C. (2010). “Not just right experiences” and obsessive-compulsive symptoms in non-clinical and clinical Italian individuals. Journal of Anxiety Disorders, 24, 879–886.Find this resource:

Goodman, W. K., & Insel, T. R. (2009). Deep brain stimulation in psychiatry: concentrating on the road ahead. Biological Psychiatry, 65(4), 263–266.Find this resource:

Gottesman, I. I., & Gould, T. D. (2003). The endophenotype concept in psychiatry: etymology and strategic intentions. American Journal of Psychiatry, 160, 636–645.Find this resource:

McKay, D., & Moretz, M. W. (2009). The intersection of disgust and contamination fear. In B.O. Olatunji & D. McKay (Eds.), Disgust and its disorders: Theory, assessment, and treatment implications (pp. 211–227). Washington, DC: American Psychological Association.Find this resource:

Najmi, S., & Amir, N. (2010). The effect of attention training on a behavioral test of contamination fears in individuals with subclinical obsessive-compulsive symptoms. Journal of Abnormal Psychology, 119, 136–142.Find this resource:

Obsessive Compulsive Cognitions Working Group (1997). Cognitive assessment of obsessive-compulsive disorder. Behavior Research and Therapy, 35, 667–681.Find this resource:

Rachman, S., & de Silva, P. (1978). Abnormal and normal obsessions. Behaviour Research and Therapy, 16, 233–248.Find this resource:

Rachman, S., & Hodgson, R. (1980). Obsessions and compulsions. Englewood Cliffs, NJ: Prentice-Hall.Find this resource:

Salkovskis, P., & Harrison, J. (1984). Abnormal and normal obsessions: A replication. Behaviour Research and Therapy, 22, 549–552.Find this resource:

Steketee, G., Chambless, D. L., & Tran, G. (2001). Effects of Axis I and II comorbidity on behavior therapy outcome for obsessive compulsive disorder and agoraphobia. Comprehensive Psychiatry, 42, 76–86.Find this resource:

Steketee, G., & Frost, R. O. (2007). Treatment of compulsive hoarding: Therapist guide. New York: Oxford.Find this resource:

Steketee, G., Frost, R. O., Tolin, D. F., Rasmussen, J., & Brown, T. A. (2010). Waitlist controlled trial of cognitive behavior therapy for hoarding disorder. Depression and Anxiety, 27, 476–484.Find this resource:

Steketee, G., & Shapiro, L. (1995). Predicting behavioral treatment outcome for agoraphobia and obsessive compulsive disorder. Clinical Psychology Review, 15, 317–346.Find this resource:

Tolin, D. F., Frost, R. O., & Steketee, G. (2010). A brief interview for assessing compulsive hoarding: The Hoarding Rating Scale. Psychiatry Research, 178, 147–152. (p. 532) Find this resource: