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Anxiety Disorders: Future Directions for Research and Treatment
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Acknowledgements
The advice and assistance provided by the following individuals to this project is gratefully acknowledged:
Richard Allon, Ph.D., C. Psych. Dr. Danielle Bourdeau Dr. Ann Carter Ms. Cynthia Crawford Ms. Sharon Doell Ms. Fiona Downie Dr. Nady el Guebaly Ms. Helen Goh Ms. Veronika Huta Ms. Eugenia Reputur-Moreno John Service, Ph.D. Ms. Carol Silcoff Ms. Anne Strickland Dr. Mark Tapper |
Ms. Natasha Ing Ms. Francine Knoops Ms. Maureen Kraemer Terry Krupa, Ph.D. Ms. Ina Leeuw Ms. Laura Lin Dr. Werner Pankratz Ms. Bonnie Pape Dr. Quentin Rae-Grant Rachel Thibeault, Ph.D. Dr. Diane Watson Ms. Stephanie Wilson |
Anxiety disorders are among the most common mental health problems experienced by Canadians. A number of effective treatments exist for these disorders. However, recent research suggests that health and mental health professionals may lack knowledge of appropriate treatments for anxiety disorders, and may use treatments which are not based on sound empirical evidence.
To contribute to the empirical knowledge base of effective treatment strategies for anxiety disorders, and to further discussions on these issues among stakeholders in the mental health field, a critical review of the evidence-based treatment literature was commissioned by the Health Promotion and Programs Branch of Health Canada. The report entitled, Anxiety Disorders and their Treatment: A Critical Review of the Evidence-Based Literature is available under separate cover. A discussion paper, the present report, was also prepared based on the findings of the review. Both reports were prepared by Martin Antony, Ph.D, and Richard Swinson, M.D., at the Clarke Institute of Psychiatry in Toronto, Ontario. The tireless efforts of the authors to ensure the successful completion of this project are much appreciated.
This discussion paper should be of interest to policy makers, administrators, professionals in the mental health and health care fields, researchers, non-governmental organizations, consumer and family groups, and anyone involved in the treatment of anxiety disorders.
Anxiety disorders are among the most prevalent mental health problems experienced by Canadians. Although effective treatment approaches exist for these disorders, research suggests that mental health and health care professionals often lack appropriate knowledge about effective treatments, and may use treatments with little empirical support.
To contribute to the empirical knowledge base of effective treatment strategies, and to further discussions among stakeholders in the mental health and health care fields on this issue, Health Canada commissioned a critical review of the evidence-based treatment literature and a discussion paper.
The studies reviewed in the reports were selected according to several author-defined criteria, outlined in detail in the literature review report. Although these studies represent the existing “state of the art” in the anxiety treatment literature, the authors identify a number of methodological limitations. These include: possible inadequacy of treatment delivery in research studies (e.g., inconsistency of measurement of treatment compliance across studies); limited outcome measures (e.g., focus on symptom measurement to the exclusion of non-medical dimensions of the disorder); and use of different assessment instruments to determine the presence or absence of symptoms of anxiety disorders (making comparisons between studies difficult). The authors also note that the quality of research varies greatly across the anxiety disorders; studies of panic disorder are quite advanced, whereas studies of the other anxiety disorders suffer from a number of methodological flaws (e.g., small sample sizes) which limit their usefulness.
The authors focus on the six major types of anxiety disorders: panic disorder with (PDA) and without (PD) agoraphobia, obsessive-compulsive disorder (OCD), social phobia, generalized anxiety disorder (GAD), specific phobia, and posttraumatic stress disorder (PTSD), and provide information on prevalence, risk factors, comorbidity patterns, health care utilization, and economic costs associated with these disorders. Acute stress disorder, a variant of PTSD with a briefer duration, agoraphobia without a history of panic disorder, and anxiety disorders induced by a general medical condition or a substance are not discussed, due to the lack of research on specific strategies for dealing with these conditions. Finally, anxiety disorders classified as “not otherwise specified” are not discussed in this review due to the heterogeneity of this category and the lack of studies describing individuals who receive this diagnosis.
Most of the anxiety disorders are more common among women than among men. A one-year prevalence rate of nine percent for men and 16 percent for women for anxiety disorders was reported in the Mental Health Supplement of the 1990 Ontario Mental Health Survey. Lifetime prevalence rates for experiencing any anxiety disorder (reported in North American epidemiological research), vary from 10.4% to 25.1%. Lifetime prevalence rates for specific anxiety disorders range from 3.5% for panic disorder to 13.3% for social phobia in recent epidemiological research (see Appendix 1).
A number of risk factors and socio-demographic variables have been identified for these disorders and include severe abuse, parental mental disorder, parental behaviour (e.g., a tendency to be overprotective), and family history of anxiety. On average, many of the anxiety disorders tend to first develop when individuals are in their twenties, although there is much variation across the anxiety disorders with respect to the range of ages at which the disorders begin. Risk factors for developing specific types of anxiety disorders have been identified. These include: perceived negative impact of stressful events, anticipation of a major life event, substance abuse, parental behaviour, and being under 65 years of age (for PDA and PD), childhood history of separation anxiety, infrequent dating, and parental behaviour (for social phobia), anxiety in childhood (for GAD and PDA), and being female (for specific phobia, PDA and GAD). Experiencing traumatic events has been identified as a risk factor for specific phobia, social phobia and PTSD. Not all individuals who experience these risk factors develop anxiety disorders. The role of mediating variables, such as social support or biological predispositions, is under investigation.
The authors report that most individuals with anxiety disorders have another (comorbid) mental health problem, such as another form of anxiety disorder, depressive mood disorder (i.e., major depression or dysthymia), alcohol or substance abuse, eating disorders, and personality disorders. Interestingly, social phobia has been found to predate mood disorders as well as other anxiety disorders. This finding suggests that comorbidity patterns could have preventive implications.
The direct and indirect costs of anxiety disorders to the Canadian economy remain to be investigated. American data, however, provide some information. One study found that persons with anxiety or depressive disorders cost an average of $2390 ($US) for a six-month baseline period, compared to $1397 ($US) for those without anxiety or depressive diagnoses. Other studies show that anxiety disorders are also associated with lost productivity in the workplace. Anxiety disorders are also associated with frequent use of the health care system. Research suggests that individuals with anxiety disorders have more frequent contact with the health care system than does the general population. These individuals tend to seek help from the general health care system, as opposed to the mental health care system.
Pharmacological approaches and cognitive-behavioural therapy (CBT; a form of psychotherapy) have been found to be effective in the treatment of anxiety disorders. Pharmacological approaches, including antidepressants and antianxiety medications, have been shown to be helpful in treating each of the anxiety disorders, excluding specific phobias. Selective serotonin reuptake inhibitor (SSRI) antidepressants have proven to be the pharmacological treatment of choice for OCD. Preliminary research also suggests that the SSRI's may be useful for most types of anxiety disorders. Tricyclic antidepressants (TCA's) appear to be effective for treating both PDA and PD, whereas MAOI (monoamine oxidase inhibitors) antidepressants appear to be the treatment of choice for social phobia. The benzodiazepines (antianxiety medications) appear to be useful for treating PDA, PD, social phobia, and GAD. Other anxiolytics, such as buspirone, have been shown to be helpful for treating GAD, but not for the other anxiety disorders.
Cognitive-behavioural therapy (CBT) appears to be an effective psychotherapeutic treatment for decreasing symptoms in each of the anxiety disorders. However, few properly controlled studies have been conducted to evaluate the effectiveness of CBT (and of most psychological treatments) for PTSD and (appropriately diagnosed) specific phobias. CBT is more effective for anxiety disorders than other psychological treatments and is at least as effective as pharmacological approaches. For a variety of disorders, CBT appears to have more lasting effects following termination of treatment than do medications. Interestingly, CBT has been shown to help patients discontinue their medications (e.g., benzodiazepines) without relapse.
CBT strategies shown to be helpful include cognitive restructuring (i.e., changing anxious thoughts, interpretations, and predictions into more rational and less anxious thoughts), exposure to feared objects and situations, and relaxation training. Existing evidence suggests that exposure-based treatments are effective for phobic disorders, PTSD and OCD. Applied tension has been shown to be helpful for specific phobias involving blood and injections (by increasing blood pressure in order to prevent the fainting that is often associated with such phobias). Interestingly, the role of family support in cognitive-behavioural treatments for PDA has been explored, with findings suggesting that participation of spouses in treatment is beneficial to treatment outcomes. New CBT strategies, such as eye movement desensitization and reprocessing and computer-administered CBT, are currently being tested.
Interventions with reduced therapist contact (e.g., self-help books and treatment by telephone) have proven effective with PD and PDA. Little is known about the usefulness of these interventions for the other types of anxiety disorders. In addition, there is a dearth of controlled research studies on the role of self-help groups and other forms of mutual aid in helping individuals with anxiety disorders cope with the impact of the illness. Anecdotal evidence suggests that some individuals find the support and assistance (both practical and emotional) available through participation in these groups to be helpful.
Debate exists among clinicians and researchers regarding the relative efficacy of pharmacological and psychotherapeutic approaches, as well as the relative importance of biological and psychological processes in the etiology of anxiety disorders. Based on their review of the literature, the authors indicate that there is little consistent evidence that combining CBT and medication is any more effective than using either treatment alone.
The authors raise two important considerations with regard to the treatment of anxiety disorders. First, they discuss the possible side effects of some antianxiety medications, particularly the benzodiazepines. Common side effects associated with the latter include sedation, fatigue, ataxia, slurred speech, and amnesia. Withdrawal symptoms and possibility of relapse and recurrence of symptoms have also been associated with discontinuation of the benzodiazepines.
Also addressed by the authors is the appropriateness of treatments offered to individuals with anxiety disorders. Research suggests that health care (e.g., general practitioners) and mental health care professionals (outside of specialized anxiety disorders clinics) often lack knowledge of appropriate treatments for anxiety disorders, and often do not use treatments with the most empirical support. The authors identify a number of implications flowing from their findings for possible future consideration by the appropriate stakeholders in the mental health and health care fields. In the area of professional care, the following are outlined: education of health and mental health professionals (including general practitioners, psycho- logists, psychiatrists, occupational therapists, social workers, psychiatric nurses, et cetera) on effective treatment of the anxiety disorders; evaluation of the most effective means of educating professionals; development and dissemination of practice guidelines and structured assessments to health and mental health professionals; increased communication and better linkages between general practitioners and mental health practitioners (including social workers, occupational therapists, psychiatric nurses, et cetera), and between formal institutional services and community and voluntary services regarding treatment of the anxiety disorders. The authors also suggest that efforts should be aimed at increasing public awareness of the anxiety disorders and their treatment. Possible avenues for doing so include: development of self-help or self-care handbooks, preparation of anxiety disorder fact sheets, and dissemination of information through national public education campaigns, such as Mental Illness Awareness Week (MIAW) (spearheaded by the Canadian Psychiatric Association).
The authors also highlight a number of issues in which further research is warranted. These include: risk (and protective) factors for developing anxiety disorders; the implications of comorbid conditions on the treatment of anxiety disorders, the relative and combined efficacy of CBT and medications for anxiety disorders over both the short- and long-term (other than for OCD, PD and PDA for which evidence already exists); and the sequencing of treatments when combined treatments are used. Other issues to be explored include the development of predictors of effective treatments for individuals, including those with one or more comorbid conditions; the effectiveness of treatment by non-mental health professionals (e.g., general practitioners); and the effectiveness of self-help approaches (e.g., self-help groups) and treatments involving minimal therapist contact. Methodologically- sound research on the effectiveness of other forms of psychotherapeutic approaches (e.g., psychodynamic and humanistic approaches) for the treatment of anxiety disorders is recommended. In addition, more research is needed on the effectiveness of newer treatments, such as the SSRI's and other antidepressant medication.
Inclusion of a broad range of outcome variables in treatment studies, and evaluation of measurement instruments used to assess the presence or absence of anxiety symptoms are also needed. Meta-analytic studies, other than for PDA and OCD where they have been used, are recommended to shed light on the treatment efficacy of various interventions for the anxiety disorders.
Some research recommendations specific to each type of anxiety disorder are identified. For panic disorder with and without agoraphobia, research is needed on the effects of various forms of treatment in specific populations, including the elderly, children, culturally diverse groups, and individuals with multiple psychological problems (e.g., anxiety disorders and substance abuse). For OCD, research on psychosocial interventions (e.g., exposure, response prevention, and cognitive therapy) is needed, and more needs to be learned regarding the process of therapeutic change. Many of the older uncontrolled studies should be repeated, using appropriate controls, adequate sample sizes, diagnoses using DSM-IV criteria (as measured by structured interviews), and adequate long-term follow-up. With respect to social phobia, further research is needed to confirm preliminary research findings that CBT is at least as effective as pharmacological approaches in the short-term and probably more effective than medications in the long-term. In addition, research on the role of self-help/mutual aid remains to be undertaken. For GAD, given that relatively few studies are based on recent criteria, it is important that psychological and pharmacological treatments be evaluated using properly diagnosed patients and a broad range of measures (including cognitive assessments). With respect to specific phobia, studies that explore the efficacy of behaviour therapy with a broader range of diagnosed phobias (e.g., heights, storms, flying, et cetera) are needed. In addition, the efficacy of using strategies (e.g., medications, interoceptive exposure) shown to be effective for treating panic disorder for different specific phobia types remains to be investigated.
