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date: 22 April 2019

Future Directions in Anxiety Disorders Research

Abstract and Keywords

This chapter reviews the latest advances in knowledge about anxiety-based problems, and proposes future directions for anxiety disorders research. Areas discussed include diagnostic issues (including proposed changes for DSM-V), epidemiology and descriptive psychopathology (e.g., age of onset, patterns of comorbidity, gender, ethnicity, core features), etiology, and treatment.

Keywords: anxiety disorders, etiology, psychopathology, research, treatment

In the past few decades, our knowledge about the nature, causes, and best practices for managing anxiety disorders and related conditions has expanded dramatically. As reviewed throughout this book, advances have been made in the classification and descriptive psychopathology of anxiety disorders, and there is now considerable evidence supporting the roles of both psychological factors (e.g., experiential and situational avoidance, biases in attention and memory, interpretational biases, traumatic experiences, observational learning, verbal transmission of information, family accommodation, personality traits) and biological factors (e.g., genetics, effects of neurotransmitters, endocrine changes, activity in particular brain regions, etc.) in the etiology and maintenance of anxiety disorders. Moreover, as readers will appreciate, the schisms between “psychological” and “biological” factors are disappearing as we understand more about the interactions between the brain and our experiences. In addition, effective psychological and pharmacological treatments now exist for all of the anxiety disorders, several of which were previously considered to be more or less untreatable.

Despite these advances, there remains much to be learned about the nature and causes of anxiety disorders, and about the best ways to assess and treat these conditions in clinical practice. The purpose of this chapter is to review exciting new directions in anxiety disorders research, and to look ahead to areas that remain to be studied in depth.

Future Directions in the Classification of Anxiety Disorders

Although the diagnostic criteria for many of the anxiety disorders have been revised and updated over time, the list of basic anxiety disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM) has mostly remained unchanged since the publication of DSM-III (American Psychiatric Association, 1980). An exception was the introduction of acute stress disorder in DSM-IV (American Psychiatric Association, 1994), which, it has turned out, has been a controversial diagnosis unlikely to survive into DSM-V. The development of DSM-V is now moving forward, with a tentative publication date of 2011 (see In the context of the initial planning of DSM-V, a number of questions and issues are being raised (Rounsaville et al., 2002), including:

  1. 1. What is the most appropriate definition of the term mental disorder?

  2. 2. What is the best way to establish the validity of psychiatric diagnoses?

  3. (p. 668) 3. To what extent should the classification of psychopathology rely on a dimensional approach that describes the severity of symptoms along continuous dimensions, as opposed to the current categorical approach that describes symptoms and syndromes as either present or absent?

  4. 4. Is it possible to improve consistency between the DSM-V and the next edition of the World Health Organization's International Classification of Diseases (ICD-11)?

  5. 5. How can DSM-V be improved to be more relevant across a wider range of socioeconomic strata and cultures?

  6. 6. Is it possible to develop strategies for reducing our reliance on clinical judgment, in favor of increased use of laboratory tests, psychological testing, and standardized self-report rating scales? Such an approach would make it easier to use DSM-V in a wider range of nonpsychiatric settings, perhaps for early detection of mental disorders.

Another important question that researchers are now asking concerns the extent to which etiology should be considered in the classification of mental disorders, as it is in many medical conditions (Charney et al., 2002). Starting with the publication of DSM-III in 1980, the last few editions of the DSM have taken a descriptive and atheoretical approach to classification, purposely avoiding issues of etiology. Are we now at a stage in our understanding of the etiology of anxiety disorders that etiological factors should be considered in classification? Although it may be decades before our knowledge of etiology and pathophysiology is complete enough to adequately inform our classification of mental disorders, some have raised the question of whether our current state of knowledge is advanced enough to have at least some of our nomenclature based on what we know about etiology. In fact, Charney et al. (2002) suggest a possible new multiaxial classification system consisting of five axes:

  1. Axis I: Genotype (e.g., identification of genes that relate to risk factors, protective factors, and response to particular treatments)

  2. Axis II: Neurobiological phenotype (e.g., identification of particular patterns in neuroimaging, cognitive function, and emotional regulation that relate to genotype and response to particular treatments)

  3. Axis III: Behavioral phenotype (e.g., the range and frequency of expressed behaviors that are associated with the genotype, neurobiological phenotype, the environment, in response to particular treatments)

  4. Axis IV: Environmental modifiers or precipitants (e.g., environmental variables that affect the behavioral or neurobiological phenotypes)

  5. Axis V: Therapeutic targets and response

Although important decisions remain to be made by those developing DSM-V, the outcome of these general discussions could have a considerable impact on how anxiety disorders and other psychological problems are classified. In addition to these general issues, there have also been preliminary discussions about issues that are more specifically relevant to the anxiety disorders. For example, some investigators have argued that OCD should no longer be classified as an anxiety disorder, and instead should be grouped with other conditions commonly referred to as obsessive-compulsive (OC) spectrum disorders (Bartz & Hollander, 2006). Disorders typically included in the OC spectrum include body dysmorphic disorder, hypochondriasis, tic disorders, and others, though there is not complete agreement about which conditions belong. The proposal to group OCD with other OC spectrum disorders is based on the fact that these conditions are associated with OC features and are often similar to OCD with respect to patient characteristics, course, comorbidity, neurobiology, and response to treatment. In a recent survey of 187 OCD experts (108 psychiatrists, 69 psychologists, and 10 others) regarding the proposal to remove OCD from the anxiety disorders and group it with various OC spectrum disorders, 60% agreed and 40% disagreed with the proposal (Mataix-Cols, Pertusa, & Leckman, 2007). There was significantly more support for the proposal among psychiatrists (75%) than among other professionals (40%–45%).

In addition to removing OCD from the anxiety disorders, some researchers have argued that generalized anxiety disorder (GAD) and posttraumatic stress disorder (PTSD) have more in common with depression than they do with other anxiety disorders. For example, Gamez, Watson, and Doebbeling (2007) found that the personality features associated with GAD and PTSD were more similar to those associated with depression than to those associated with other anxiety disorders. Using data from a large epidemiological sample, Slade and Watson 2006 used confirmatory factor analysis to examine the relationships among various mental disorders. The study identified a distress factor that included such disorders as major depression, dysthymic disorder, GAD, and PTSD. A separate (p. 669) fear factor included disorders such as social phobia, panic disorder, agoraphobia, and OCD. Based on these and other findings, some have argued that GAD and PTSD might be better grouped with depressive disorders, perhaps under the general heading of distress disorders.

It is still too early to know how anxiety disorders will be classified in DSM-V. Calls will likely be made for all kinds of changes in the ways in which anxiety disorders are organized, as well as for changes in the diagnostic criteria for particular anxiety disorders in the next edition of the DSM. Despite the potential benefits of making such changes, revisions to the DSM also come with important costs (e.g., training clinicians in the new nomenclature, research based on new diagnostic criteria, impact on insurance companies, legal systems, etc.). Weighing the costs and benefits will be a significant challenge in the process of revising DSM-IV.

Epidemiology and Descriptive Psychopathology

Although the literature on the epidemiology and descriptive psychopathology of anxiety disorders is quite advanced, many questions remain to be answered. Some examples are provided in the following sections.

Age of Onset

Many studies have reported on the age of onset for anxiety disorders. However, three issues that limit the conclusions that can be drawn from this literature include (1) the reliance on retrospective reports of questionable validity, (2) the inconsistent manner in which data are coded from individuals who report having had their symptoms for “as long as they can remember,” and (3) the fact that age of onset studies have typically failed to distinguish between the age of onset for the symptoms of a disorder versus the age of onset for the syndrome. An exception is a study on specific phobias by Antony, Brown, and Barlow 1997 that asked about the age of onset for participants' excessive fear, as well as the age at which the fears began to cause significant distress and impairment (i.e., the age at which full diagnostic criteria were met). This study found that the age of onset for the full disorder was on average 9 years later than the age of onset for the initial symptoms (i.e., extreme fear without clinically significant distress or impairment). Future studies will need to distinguish between the onset of anxiety symptoms and the onset of the anxiety disorder.

Gender and Anxiety Disorders

It is well established that anxiety disorders occur more frequently in women than in men, although sex differences are considerably smaller in some anxiety disorders (e.g., social phobia, specific phobias of blood/needles) than in others (e.g., panic disorder, GAD). Although possible reasons for sex differences across anxiety disorders have been identified (e.g., societal expectations, biological differences, etc.), considerable research is still needed to fully understand the reasons for the gender differences that exist. In addition to variations in the presence of anxiety disorders across the sexes, there may also be differences in the ways in which these disorders are expressed (e.g., symptom profile, etc.) across the sexes—an issue for which there is currently very little research available.

Ethnicity and Anxiety Disorders

There are some studies on the effects of culture, religion, and related factors on the prevalence and expression of anxiety disorders, but much of the existing research has simply measured the frequency of anxiety symptoms across different groups. Very little is known about reasons for cultural differences in the expression of anxiety. Nor are there adequate data addressing the expression of anxiety symptoms and syndromes that are different from those described in the DSM-IV anxiety disorders section. Better understanding the nature of anxiety disorders across ethnic groups may lead to the development of more culturally appropriate treatments, an issue to which we will return later in this chapter.

Patterns of Comorbidity

Patterns of comorbidity between particular anxiety disorders and other conditions (e.g., other anxiety disorders, mood disorders, substance use disorders, personality disorders, etc.) are well established. However, much less is known about the reasons for comorbidity. For example, are the OCD-like behaviors seen in people with autism, eating disorders, and certain impulse control disorders etiologically related to those observed in people with OCD? Furthermore, what accounts for the high rates of co-occurrence between anxiety disorders and depression? Although researchers have begun to address questions such as these, there is still much more work to be done in this area. Because comorbidity is very common among people with anxiety disorders, and certain types of comorbidity have been found to affect the outcome of treatment, improved outcomes may result from gaining a better understanding of the nature and causes of comorbidity.

(p. 670) Understanding Heterogeneity and Subtypes

It is generally accepted that anxiety disorders are heterogeneous conditions. DSM-IV (American Psychiatric Association, 1994) acknowledges heterogeneity within several anxiety disorders, though only to a limited extent. Examples include requiring that a clinician specify which of five types (i.e., animal type, natural environment type, blood-injection-injury type, situational type, other type) best describes a patient's specific phobia, whether a patient's panic disorder is accompanied by agoraphobia, whether a patient's social phobia is generalized, whether a patient's OCD is accompanied by poor insight, whether a patient's PTSD is acute versus chronic, and whether the patient's PTSD had a delayed onset.

Some investigators have questioned whether these are the best ways to describe the variability that occurs within anxiety disorders. For example, Antony, Brown, and Barlow 1997 questioned the value of including the five specific phobia types in DSM-IV. Others have developed alternative ways of describing heterogeneity. For example, Heimberg, Holt, Schneier, Spitzer, and Liebowitz (1993) proposed three subtypes (generalized, nongeneralized, discrete) of social phobia. Similarly, investigators have proposed various ways of capturing heterogeneity in OCD—for example, taking into account the presence versus absence of tics, the specific symptom content (e.g., contamination and washing, doubting and checking, incompleteness concerns, etc.), and other factors (e.g., Leckman et al., 1995; Rasmussen & Eisen, 1992; Rosario-Campos et al., 2006; Summerfeldt, Richter, Antony, & Swinson, 1999). More research is needed to better understand heterogeneity within anxiety disorders and whether different symptom profiles are associated with different responses to treatment.

Core Features of Anxiety Disorders

Investigators are increasingly recognizing that anxiety disorders share various basic core features, and that effective psychological treatments can be developed to target these core dimensions, regardless of the specific diagnosis (see Chapter 33). Transdiagnostic approaches to understanding anxiety disorders can also help to conceptualize patterns of comorbidity that are often observed in patients. Antony (2002) observed a number of dimensions that appear to be relevant to all anxiety disorders. These include the presence of fear, anticipatory anxiety, and worry, situational avoidance, avoidance of thoughts and feelings, interoceptive anxiety (i.e., anxiety sensitivity), and overprotective behaviors (e.g., compulsive rituals, safety behaviors, etc.). In addition, it was proposed that these symptoms may be moderated by other factors such as skills deficits, family issues, life stress, and medical complications.

Antony and Rowa 2005 refined this list, suggesting a number of core features that are important to assess and treat: anxiety cues and triggers (including situational cues, interoceptive cues, and cognitive cues), avoidance behaviors (including situational avoidance and experiential avoidance), compulsions and overprotective behaviors (i.e., safety behaviors), physical symptoms and responses, skills deficits, environmental and family factors, and medical and health issues. They suggested that by understanding symptoms associated with these dimensions, individualized treatment protocols can be developed to target these core features, particularly when additional relevant information has been assessed (e.g., associated distress and functional impairment, development and course of the problem, treatment history, and associated problems and comorbidity).

Although the value of considering these core dimensions may be evident when thinking about anxiety disorders from a cognitive behavioral perspective, it is quite possible that clinicians working from a different perspective might identify very different core features. It remains to be determined whether these are in fact the most important dimensions for understanding anxiety disorders, and whether administering individualized treatments based on these assessment data will in fact lead to better outcomes than standardized treatments designed to target particular disorders.

Understanding the Similarities and Differences Among Relevant Constructs

The definitions and boundaries for basic constructs (e.g., fear, anxiety, panic) remain unclear. For example, whereas some investigators argue that fear and anxiety are distinct emotional states (e.g., Barlow, 2002), others do not distinguish between these experiences, arguing that panic is simply an intense form of anxiety (e.g., Clark, 1986; Rapee, 1996). Similarly, whereas some researchers (e.g., Barlow, 2002) have argued that panic and fear are identical states, others (e.g., Klein, 1993) have argued that panic and fear are different, and that they reflect unique pathophysiological processes.

The definition of worry is also in need of refinement, and it needs to be differentiated from other cognitive processes that occur in people with anxiety disorders. Some investigators have proposed that (p. 671) worry is a purposeful activity designed to reduce anxiety by distracting individuals from feared imagery and sensations (e.g., Borkovec, Alcaine, & Behar, 2004). Beck and others (e.g., Beck, Emery, & Greenberg, 1985) have argued that negative thoughts and predictions are responsible for increased anxiety as well as other unpleasant emotions. What remains unclear is the relationship between worry and negative automatic thoughts, and what is actually happening in people's minds when they worry.

Similarly, the relationships among experiences such as worries, obsessions, intrusive memories, depressive ruminations, and other types of distressing cognitive activity are poorly understood, as are the relationships between relevant traits, such as impulsivity and compulsivity. Advances in research on information processing and the pathophysiological underpinnings of these constructs may help to answer questions about the nature of these states, and the boundaries among them.

Etiology of Anxiety Disorders

As reviewed throughout this book, there have been many advances in our understanding of the factors that contribute to the onset and maintenance of anxiety disorders. It is now well established that anxiety disorders stem from a complex interaction between our experiences (e.g., negative experiences, modeling, transmission of information, reinforcement from the environment, parenting, relationships with family and peers, etc.), how we process information (e.g., biases in interpretation, attention, and memory), and other individual differences (e.g., genetics, neuroanatomy, neurotransmitter activity, hormonal activity, personality, etc.). It appears that our genes influence the types of experiences we have, as well as the ways in which we process information. Formally disparate avenues of research are increasingly converging, as investigators try to understand the relationship between biological and psychological processes. Research is ongoing in these areas, and it is almost certain that our understanding of the etiology of anxiety disorders will continue to improve in the future.

Because anxiety disorders often begin early in life, research on children and adolescents will be key to discovering the most important risk factors for developing anxiety disorders. In addition, prospective and longitudinal studies on the development and course of anxiety disorders are greatly needed; retrospective studies have dominated the literature thus far.

Recent Developments in the Treatment of Anxiety Disorders

Effective treatments now exist for all of the anxiety disorders. Nevertheless, some people do not benefit from existing treatments, and those who do respond to treatment often experience only partial improvement. Therefore, the focus on much of the recent treatment research has been on trying to understand the relative effects of various treatment approaches, as well as identifying strategies for improving outcomes with existing treatments (Antony, Ledley, & Heimberg, 2005). Examples of the types of questions addressed in recent studies include:

  • • Is there an advantage (or disadvantage) of group treatment versus individual treatment for anxiety disorders (Anderson & Rees, 2007; Mörtberg, Clark, Sundin, Åberg, & Wistedt, 2007)?

  • • Does the frequency (intensity) of sessions affect outcome during psychological treatment of OCD (Abramowitz, Foa, & Franklin, 2003) or panic disorder (Craske et al., 2006)?

  • • Do medication, cognitive behavioral therapy (CBT), or a combination of these treatments lead to greater improvement (Davidson et al., 2004; Foa et al., 2005)?

  • • Can CBT be used to help patients discontinue their use of benzodiazepines (Gosselin, Ladouceur, Morin, Dugas, & Baillargeon, 2006)?

  • • Does social skills training enhance outcomes with CBT for social phobia (Herbert et al., 2005)?

  • • Does home-based CBT work better than office-based CBT for OCD (Rowa et al., 2007)?

  • • Does including parents in the treatment of child anxiety disorders lead to better outcomes (Wood, Piacentini, Southam-Gerow, Chu, & Sigman, 2006)?

In addition, there have been several new directions in anxiety disorders treatment research that have generated considerable interest. First, a number of recent studies have found that D-cycloserine (a partial glutamatergic agonist that enhances memory and learning), leads to better treatment outcomes during exposure therapy, relative to exposure alone (Hofmann, 2007). This line of research opens new possibilities for a mechanistically informed combining of pharmacological and psychological treatments. Second, a number of recent studies suggest that “transdiagnostic” psychological treatments that focus on a patient's particular anxiety and mood symptoms, irrespective of diagnosis, can lead to significant improvement (Barlow, Allen, & Choate, 2004; Norton, Hayes, & Hope, 2004). Finally, there (p. 672) has been great interest in mindfulness meditation and acceptance-based approaches to treating anxiety disorders (Orsillo & Roemer, 2005).

Despite the volume of research devoted to developing new treatments and improving upon existing treatments, there is still much that remains unknown. First, there are many issues for which evidence regarding the best ways to administer treatment is contradictory. For example, whereas some studies have shown that adding cognitive strategies to exposure for social phobia leads to improved outcomes (Mattick & Peters, 1988), other studies have found little benefit of combining these approaches over exposure alone (Mersch, 1995). Similarly, whereas some studies have shown that distraction interferes with the effects of exposure for phobias (Kamphuis & Telch, 2000), other studies have found no effects of distraction (Antony, McCabe, Leeuw, Sano, & Swinson, 2001), and some have shown benefits of distraction both within and across sessions (Oliver & Page, 2008). More research is needed to better understand the source of these discrepancies.

There are many treatment approaches for which research is lacking. For example, studies that have investigated the effects of combining medications and CBT for anxiety disorders have almost always studied the effects of concurrent treatments, rather than sequential treatments. Therefore, little is know about the effects of combining treatments sequentially (e.g., CBT followed by medication, medication followed by CBT). Little is known about the best ways to combine psychological treatment strategies as well. For example, should cognitive strategies be taught before exposure strategies? Should interoceptive exposure be taught before or after situational exposure when treating panic disorder? Should patients use cognitive strategies during their exposure practices? When should mindfulness-acceptance based approaches be used?

In addition, there are many popular anxiety treatments for which there is very little research, including insight-oriented psychotherapy, hypnosis, biofeedback, herbal treatments, and various complementary and alternative interventions (e.g., acupuncture). Similarly, very little is known about the effects of lifestyle changes (e.g., changing habits related to exercise, diet, stress management, and sleep) on the course of anxiety disorders. Given the interest of the public in these types of treatments (Roy-Byrne et al., 2005), the lack of empirical evidence about their utility is unfortunate, and must be rectified.

Identifying the Most Important Components of Effective Treatment

Most evidence-based psychological treatments include groups of strategies (e.g., cognitive restructuring, relaxation training, exposure, skills training, psychoeducation, etc.) that in combination have been shown to be effective. However, dismantling studies have often found that some of the strategies used in standard protocols are more important than others. For example, breathing retraining seems to add little to the treatment of panic disorder (Schmidt et al., 2000). The eye movements proposed to be an important component of eye movement desensitization and reprocessing (EMDR) have been found to offer little benefit beyond the effects of the other components of EMDR, such as exposure (Lohr, Tolin, & Lilienfeld, 1998). Finally, among the interoceptive exposure exercises used in the treatment of panic disorder, some (e.g., breathing through a straw, hyperventilating, spinning) have been found to be much more potent for triggering feared sensations than other exercises (e.g., staring at a light and then reading) (Antony, Ledley, Liss, & Swinson, 2006).

There are still many questions about the most important components of standard treatments that remain to be answered. For example, which cognitive strategies (e.g., behavioral experiments, cognitive restructuring, completion of thought records, challenging core beliefs, perspective shifting, etc.) are most effective? Is imaginal exposure useful, and if so, under what conditions? What is the most effective way to administer imaginal exposure? How much time should be devoted to various treatment components? Which methods of relaxation (e.g., progressive muscle relaxation, breathing retraining, imagery) are most effective for treating worry and generalized anxiety? What is the best way to assess whether a particular patient with social phobia is likely to benefit from social skills training in addition to exposure and cognitive restructuring?

Identifying the Mechanisms Through Which Treatment Works

Although much is known about how effective various treatments are, less is known about the mechanisms through which treatments have their effects. Even for well-established strategies such as exposure, cognitive restructuring, and antidepressant medications, there is much work to be done to fully understand why these treatments work. One general approach that may help to uncover the mechanisms underlying effective treatments is (p. 673) to consider anxiety disorders and their treatments from a variety of perspectives. Straube et al. 2006 did just that in a study that examined the effects of CBT on brain activation in specific phobia. In this study, increased activation in the insula and anterior cingulate cortex was associated with specific phobia symptoms, whereas an attenuation of these brain responses was correlated with successful treatment. Further research on the relationships between cognitive behavioral and biological processes during treatment may lead to exciting new advances in our understanding of the processes through which treatments have their effects.

Understanding Predictors of Response

A number of effective treatments exist for people with anxiety disorders, and in many cases, it has been difficult to show consistent advantages of one approach over another across large groups of individuals. For example, there are few differences in outcomes across various effective antidepressants (e.g., paroxetine versus sertraline versus venlafaxine). In addition, there are few differences in the acute effects of medications, CBT, and combined treatments for most anxiety disorders. Group and individual treatments are often equally effective, and various combinations of CBT strategies often work about equally well.

Nevertheless, it is important to recognize that, although various treatments may be equivalent across large groups of patients, that does not meant that they are equally likely to be effective for any one patient. For example, patients with panic disorder who do not respond to medication alone often respond to CBT (Heldt et al., 2006). Although we understand the relative effects of various treatments, much less is known about which treatments work for whom, and under what conditions. A number of studies have investigated various predictors of outcome (e.g., comorbidity, age of onset, severity, compliance with treatment, therapist variables, etc.); nevertheless, there is still almost no research that can help a clinician to choose among various treatment options for a particular patient. Future studies may help to identify symptom profiles, genetic polymorphisms, or other factors that can help clinicians to select treatments with a high likelihood of success and fewer adverse events for a particular individual.

Developing Strategies for Treatment Resistant Cases

There has been increased recognition in recent years in the limitations of evidence-based psychological and pharmacological treatments. Investigator psycho s have begun to explore strategies for improving outcomes and for preventing the recurrence of symptoms (e.g., Antony et al., 2005). For example, in the pharmacological literature, investigators have begun to study the effects of augmenting standard pharmacological treatments with other treatments. In recent years, a number of studies have shown that combining atypical antipsychotic medications with antidepressants may lead to improved outcomes for some patients (Pollack et al., 2006). Similarly, combining a benzodiazepine with antidepressant treatment for the first month of treatment may lead to earlier improvements in patients with panic disorder, compared to treatment with an antidepressant alone (Goddard et al., 2001), and combining an SSRI with clonazepam may improve outcomes in patients with generalized social phobia (Seedat & Stein, 2004).

An exciting new development in the psychological treatment of anxiety disorders has been recent research on motivational interviewing. Motivational interviewing is an intervention designed to enhance motivation for treatment, thereby improving outcomes (Arkowitz, Westra, Miller, & Rollnick, 2008; Miller & Rollnick, 2002). Much of the work in this area has been in the fields of addictions and health psychology. However, these strategies have recently been applied with some success to the treatment of anxiety disorders (Westra & Dozois, 2006). Despite these preliminary findings, more research is needed to establish whether motivational interviewing is useful for resolving ambivalence about treatment, enhancing compliance, and improving outcomes.

In addition to developing ways of improving outcomes, there is a great need for research on prevention of relapse and recurrence following treatment of anxiety disorders. For example, little is known about the ideal duration of pharmacological treatment for anxiety disorders, and what the best ways are of dealing with recurrence of symptoms following discontinuation of treatment. Furthermore, although CBT for anxiety disorders often includes some work on strategies for maintaining gains (often at the last session), little is known about whether these strategies are effective, and how to best teach them to patients.

Studying the Effects of Treatment on Particular Groups

Much of the research on anxiety disorders has been based on adults between the ages of 18 and 65 years, primarily from Western cultures. Although (p. 674) there is a considerable literature on anxiety disorders in children, the state of knowledge regarding the treatment of anxiety in children is far behind that in adults. For example, there are relatively few studies of pharmacotherapy for anxious children (compared to studies in adults), and in the literature on psychological treatments, studies have tended to focus on the most basic issues (e.g., establishing the efficacy of treatment strategies).

The literature on treating anxiety disorders in older adults is very small, and most studies have focused on the treatment of generalized anxiety disorder (GAD). Given that studies to date have often not found CBT treatments to be more effective than alternative approaches (e.g., supportive therapies) with older adults suffering from GAD (see Chapter 48 ), there appears to be room for further development of cognitive behavioral treatments for older adults with GAD. In addition, treatments for older adults with other anxiety disorders need to be developed and tested. With the aging population, this need will only become more pressing in the coming years.

As reviewed earlier, anxiety disorders often occur in the context of other conditions. Most treatment studies include patients with certain types of comorbidity (especially other anxiety disorders), but other types of comorbidity (e.g., cognitive impairment, developmental disabilities, psychotic disorders, substance use disorders) are almost always excluded. Therefore, there is virtually no research on the treatment of anxiety disorders in the context of these other problems. This is an important gap in the literature, leaving clinicians with no empirical basis for how to manage patients suffering from an anxiety disorder as well as cognitive impairment, significant substance use, or serious mental illness.

Finally, there is very little known on how to adapt treatments for people from non-Western cultures. As reviewed by Asmal and Stein (Chapter 50), there are ethnic differences in responses to pharmacological treatments, though the reasons for these difference are poorly understood. In addition, it is not clear whether established psychological treatments for DSM-IV anxiety disorders are effective across cultures (or even across socioeconomic strata). Nor have these treatments been adapted for the range of culture-specific anxiety problems that are not represented in DSM-IV.

Improving Access to Effective Treatments

Although effective treatments for anxiety disorders are available, few practitioners use them, and few consumers are aware of them. For example, Rowa, Antony, Brar, Summerfeldt, and Swinson 2000 found that only about a third of individuals presenting for treatment at an anxiety disorders specialty clinic had previously received CBT for their anxiety disorder, though the percentage that had tried an evidence-based pharmacological approach was higher. Similarly, a study of patients with anxiety disorders in primary care found that only 25% of individuals had received appropriate medications and fewer than 10% had received an adequate psychological treatment (Stein et al., 2004).

In recent years, a number of measures have been taken to increase awareness of evidence-based treatments. For example, many psychiatry residency programs in the United States and Canada now require training in CBT (Ravitz & Silver, 2004; Sudak, Beck, & Gracely, 2002). Training in evidence-based treatments is now more common in clinical psychology training programs as well, particularly since the Society of Clinical Psychology (Division 12 of the American Psychological Association) published its list of empirically supported treatments and strategies for disseminating them (Chambless et al., 1998; Task Force on Promotion and Dissemination of Psychological Procedures [Division of Clinical Psychology, American Psychological Association], 1995).

A recent article from The Times (Hawkes, 2007) reported that in the United Kingdom, the government recently announced a plan to spend £170 million to train 3,600 therapists to deliver CBT, which will allow for almost a million additional people suffering from anxiety disorders and depression to access effective psychological treatment. In fact, the plan is for all primary care practices in the United Kingdom to soon have access to nondrug interventions. Although evidence-based treatments have yet to be supported in the same way elsewhere, attempts to deliver effective treatments for anxiety disorders in primary care settings in the United States are underway (Sullivan et al., 2007), and initial studies have shown that anxiety disorders can be effectively treated in a primary care environment (e.g., Roy-Byrne et al., 2005). There have also been attempts to develop practice-research networks to bridge the gap between science and practice (e.g., Borkovec, 2004). Nevertheless, despite these efforts, there is still much work to be done to disseminate effective treatments to practitioners and to the public.

One of the challenges in disseminating effective treatments is making them affordable and easy to access. In recent years, there has been a (p. 675) considerable amount of work directed toward these goals. Examples include the development of numerous evidence-based self-help books (Redding, Herbert, Forman, & Gaudiano, in press), videoconferencing for treating people in remote areas (e.g., Himle et al., 2006), computerized treatments (e.g., Proudfoot et al., 2004), virtual reality treatments that allow for exposure to feared cues (e.g., flying, storms, heights) in the therapist's office (Parsons & Rizzo, in press), Internet-based treatments (e.g., Carlbring et al., 2007), telephone administered treatments (e.g., Lovell et al., 2006), and brief psychological treatments (e.g., Clark et al., 1999). Although research supports the use of these cost-effective approaches, many of these treatment options are still not widely available.


Over the past few decades, enormous gains have been made in our understanding of the nature, etiology, and treatment of anxiety disorders. Nevertheless, there is still much that we don't understand about these prevalent, often disabling, conditions. Furthermore, although effective interventions exist for all of the anxiety disorders, many people do not receive evidence-based treatments, and among those who do, many continue to experience clinically significant symptoms following treatment. The challenge for anxiety disorders researchers over the next few decades will be to continue to expand our knowledge base, to improve upon current treatments, and to discover ways to ensure that those who need treatment receive it.


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