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The anxiety disorders are a group of psychological problems whose key features include excessive anxiety, fear, worry, avoidance, and compulsive rituals. The most prevalent anxiety disorders listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psychiatric Association, 1994) include panic disorder with and without agoraphobia (PDA and PD, respectively), social phobia, specific phobia, obsessive- compulsive disorder (OCD), generalized anxiety disorder (GAD), and posttraumatic stress disorder (PTSD). These disorders are the subject of this review. Other relevant disorders not discussed here include acute stress disorder (similar to PTSD, except with a shorter duration), anxiety disorder due to a general medical condition, substance-induced anxiety disorder, agoraphobia without a history of panic disorder, and anxiety disorder not otherwise specified. Very little research is available with respect to these disorders.
a. Panic Disorder with (PDA) and without (PD) Agoraphobia
The main features of PD and PDA are recurrent unexpected panic attacks (i.e., panic attacks occurring out of the blue, without any obvious situational trigger), concern about having additional attacks, worry about the consequences of the attacks, and/or a significant change in behaviour as a result of the attacks. When the symptoms of PD lead to avoidance of situations in which escape might be difficult or help might be unavailable in the event of a panic attack, the individual is said to have agoraphobia, which may include avoidance of such situations as driving, using public transportation, travelling, being alone, being in crowds, and shopping.
b. Obsessive-Compulsive Disorder (OCD)
OCD is defined by the presence of obsessions (i.e., recurrent and intrusive thoughts, images, or urges that cause marked anxiety) and/or compulsions (i.e., repetitive behaviours or mental acts that are performed to reduce the anxiety generated by one's obsessions). Typical obsessions concern contamination, doubting, and disturbing sexual or religious thoughts. Typical compulsions include washing, checking, ordering things, and counting. To meet criteria for OCD, the obsessions or compulsions must be time-consuming or distressing.
c. Social Phobia
Social phobia is an excessive or unrealistic fear of social or performance situations. Typical situations feared or avoided by individuals with social phobia include parties, meetings, eating in front of others, writing in front of others, public speaking, conversations, meeting new people, and other related situations. In social phobia, the anxiety is not exclusively related to having the symptoms of another medical or psychiatric condition noticed by others (e.g., a patient with Parkinson's disease who is anxious about others noticing a tremor would not be considered to have social phobia). In addition, the fear must interfere with the individual's life or be associated with significant distress.
d. Generalized Anxiety Disorder (GAD)
The main feature of GAD is excessive worry occurring more days than not about a number of different domains or activities (e.g., work, finances, family, health). The worry must be experienced as difficult to control and must be associated with at least three of six symptoms which include restlessness, fatigue, impaired concentration, irritability, muscle tension, and impaired sleep. To meet criteria for GAD, the worry must not be exclusively focused on the features of another disorder (e.g., worrying about having a panic attack, if the individual has PD) and must lead to significant distress or functional impairment.
e. Specific Phobia
A specific phobia is an excessive or unreasonable fear of an object or situation, usually associated with avoidance of the feared object or situation. Examples include phobias of flying, heights, animals, injections, and blood. The fear must not be related to another disorder (e.g., an individual with agoraphobia who avoids flying due to the possibility of having a panic attack), and must be associated with significant distress or functional impairment.
f. Posttraumatic Stress Disorder (PTSD)
PTSD is a disorder in which an individual experiences a traumatic event involving actual or threatened death or serious injury to oneself or others and responds to the event with intense fear, helplessness, or horror. The fear is associated with symptoms from three categories: (1) re-experiencing the event (e.g., nightmares, flashbacks, and intrusive memories); (2) avoidance and emotional numbing (e.g., avoiding talking or thinking about the trauma); and (3) symptoms of increased arousal (e.g., sleeplessness, and hypervigilance). PTSD is associated with a duration of at least one month and symptoms must cause significant distress or functional impairment to be diagnosed.
Anxiety disorders are among the most prevalent psychological problems. Lifetime prevalence rates for experiencing any anxiety disorder, reported in epidemiological research, vary from 10.4% to 25.1% (Bourdon et al., 1988); to 11.2% (Bland et al., 1988), to 24.9% (Kessler et al., 1994). The lifetime prevalence rates for specific anxiety disorders range from 3.5% for panic disorder to 13.3% for social phobia in recent epidemiological research (Kessler et al., 1994). Appendix 1 contains additional data from population health surveys, as well as an explanatory note on factors that could account for the variations in prevalence rates.
According to the Ontario Mental Health Supplement, women are more likely than men to experience anxiety disorders. The Supplement reported that the one-year prevalence rate for anxiety disorders was 9% for men and 16% for women (Ontario Ministry of Health, 1994) in the twelve months preceding the survey.
Most individuals with anxiety disorders have another mental health problem. In a 1990 study, Sanderson, Di Nardo, Rapee and Barlow found that 70% of individuals with a principal anxiety disorder diagnosis met criteria for an additional Axis I disorder, often another anxiety disorder. Specific and social phobias were the most common additional diagnoses, affecting about a third of the sample. A third of individuals with principal anxiety disorder diagnoses met criteria for depressive mood disorder (i.e., major depression or dysthymic disorder). The frequency of additional diagnoses differed across the anxiety disorders. Percentages of individuals who met criteria for one or more additional disorders were 69% for panic disorder with and without agoraphobia (PDA and PD, respectively), 58% for social phobia, 81% for generalized anxiety disorder (GAD), 53% for specific phobias, and 83% for obsessive-compulsive disorder (OCD).
Several studies have shown that alcohol and substance abuse are associated with anxiety disorders, particularly for individuals with social phobia and PDA (Cox, Norton, Swinson, and Endler, 1990; Kushner, Sher, and Beitman, 1990). Anxiety disorders, particularly social phobia and GAD, are often also associated with personality disorders (Sanderson, Beck, and Betz, 1991; Stein, Hollander, and Skodol, 1993). A recent study, based on findings from the 1984 Epidemiologic Catchment Area Survey, suggests that bipolar disorder may be associated with anxiety disorders (Chen and Dilsaver, 1995).
A number of studies have examined the impact of treatment for one disorder on comorbid conditions. Fava, Zielezny, Luria, and Canestrari (1988) found that behavioural treatment of agoraphobia led to changes in comorbid obsessive-compulsive symptoms. Similarly, Brown, Antony, and Barlow (1995) found that patients with PD who underwent CBT experienced a decrease in comorbid conditions. Comorbidity at pre-treatment was not predictive of treatment outcome. Comorbidity patterns could have possible preventive implications. For example, van Ameringen, Mancini, Styan and Donison (1991) found that social phobia predated mood disorders in 81.7% of cases and predated other anxiety disorders in 62.7% of cases among individuals with social phobia and a comorbid condition.
According to the Mental Health Supplement of the Ontario Health Survey (Ontario Ministry of Health, 1994), risk factors and socio-demographic variables associated with anxiety disorders include surviving severe abuse, parental mental disorder, low income, and being on public assistance. These were also risk factors for other mental disorders listed in the report, including mood disorders, substance abuse, and antisocial behaviour. The Supplement did not examine risk factors for particular anxiety disorders.
Family history of anxiety places individuals at risk for developing an anxiety disorder. A number of studies have shown that each of the anxiety disorders tends to run in families, and there is evidence that the relationship among anxiety disorders in different family members may be genetically mediated to some extent (Fyer, Mannuzza, Chapman, Martin, and Klein, 1995; Kendler, Neale, Kessler, Heath, and Eaves, 1992; MacDonald and Murray, 1994; Pauls, Alsobrook, Goodman, Rasmussen, and Leckman, 1995). Parental behaviour (e.g., a tendency to be overprotective, less affectionate, and more controlling) appears to be associated with the development of anxiety disorders, particularly panic disorder without agoraphobia (Gerlsma, Emmelkamp and Arrindell, 1990; Silove, Parker, Hadzi-Pavlovic, Manicavasagar, and Blazczynski, 1991). This latter finding could have implications for preventive interventions.
Risk factors have been identified for some of the individual anxiety disorders as follows:
It should be noted that not all individuals who experience these risk factors develop anxiety disorders. For example, many individuals experience traumatic events and do not develop PTSD or phobic disorders. Researchers are investigating whether mediating variables, such as social support following the event or biological predispositions, may play a role.
Data on the direct and indirect costs of anxiety disorders to the Canadian economy remain to be investigated. American data, however, provide some information. Simon et al. (1995) investigated health care costs associated with anxiety disorders and depressive disorders among persons attending three primary care clinics in a health maintenance organization in Seattle (Washington). Patients with a DSM-III-R anxiety or depressive disorder were compared to patients without significant mood or anxiety symptoms. Those 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 (Salvador-Carulla et al., 1995).
Evidence suggests that persons with anxiety disorders have more frequent contact with the health care system than does the general population (Siegel et al., 1990; Leon et al., 1995; Swinson et al., 1992). These persons tend to seek help from the general health care system, as opposed to the mental health care system (Pollard, Henderson, Frank, and Margolis, 1989; Leon et al., 1995). Swinson et al. (1992) indicate that outside of specialized anxiety disorders clinics, appropriate diagnosis and empirically validated treatments may not be provided to patients in either the health and mental health care systems. This is discussed in the following chapter.
1. Although this report does not focus on anxiety disorders induced by a general medical condition or by a substance, it is recognized that individuals may experience anxiety as a result of a physical illness (e.g., hyperthyroidism) or drug use (illicit, prescription, or over-the-counter medications).