Course and outcome of anxiety disorders in adolescents

Abstract

The aim of this article was to examine the course and outcome of anxiety disorders in German adolescents. Anxiety and other psychiatric disorders were coded based on DSM-IV criteria using the computerized Munich version of the Composite International Diagnostic Interview. About 22.6% of the adolescents who fulfilled DSM-IV criteria of any current anxiety disorders at the index investigation (T1) continued to have anxiety at the follow-up investigation (T2), 17.7% had depression, 27.4% somatoform, 6.5% substance use disorders, and 41.9% had no disorders. The factors that were significantly associated with the persistence of anxiety disorders included older age, presence of somatoform and substance use disorders, as well as a high number of negative life events at the T1-interview. Adolescents with “chronic” compared to “transcient” anxiety disorders and those without any disorders were significantly more impaired in various life domains. Despite these high levels of psychosocial impairment, only a few of them did seek professional help in the last 12 months before the T2-interview.

Introduction

Our knowledge about the course and outcome of anxiety disorders come mostly from studies among adults. According to these studies (Kessler et al., 1994, Regier et al., 1984; Wittchen, Essau, & Krieg, 1991a), most anxiety disorders tend to have an early onset, generally in childhood or early adolescence. Anxiety disorders which begin early in life are often associated with a risk of developing other psychiatric disorders and are associated with psychosocial impairment in various life domains in adulthood (Wittchen et al., 1991a). Despite this, studies examining the course of anxiety disorders in youngsters are rare.

The few existing studies on the course and outcome of anxiety disorders in children and adolescents have been inconsistent. In some studies, anxiety disorders tend to have a chronic course and a low remission rate, whereas in others they seemed to show a favorable outcome. For example, in a study by Keller et al. (1992), the mean duration of anxiety disorders at the time of interview was 4 years; 46% of these children were estimated to remain having these disorders 8 years after onset. Among children who had recovered from their initial episode of anxiety disorders, 31% had another episode by the follow-up assessment. By contrast, a prospective study by Last, Perrin, Hersen, and Kazdin (1996) showed anxiety disorders among clinically referred children to have a favorable course and outcome. Most (81.7%) of these children recovered from their anxiety disorders at follow-up. About two-thirds of the children with anxiety disorders who recovered did so within the first year of follow-up. Separation anxiety disorder showed the highest remission rate (96%) and panic disorder the lowest (70%). At a 3–4-year follow-up assessment, nearly one-third of the children with anxiety disorders developed new psychiatric disorders. In another study, Last, Hansen, and Franco (1997) examined the psychosocial functioning of young adults with histories of early-onset anxiety disorders at an 8-year follow-up assessment. Youths with “pure” anxiety disorders (i.e., without histories of comorbid depression) were functioning similar to normal controls in most social areas, except for transition to independent living (i.e., having problems separating from parents and leaving home). Adolescents with histories of anxiety and depression fared more poorly as young adults. That is, compared to pure anxious or control subjects they reported a greater incidence of psychological problems, utilized mental health services, and had problems in maintaining employment or continuing education. The predictors of adjustment difficulty in anxious subjects were male gender, presence of more than one anxiety disorders, early onset of anxiety disorder (before 13 years), severe impairment rating of anxiety disorders, and parental psychopathology.

In a longitudinal study of community children and adolescents (Cohen et al., 1993), almost one-half (47%) of those with severe symptoms of overanxious disorder at index interview were rediagnosed with overanxious disorder at a follow-up interview 2.5 years later. In the Upstate New York Study (Pine, Cohen, Gurley, Brook, & Ma, 1998), presence of anxiety disorders during adolescence predicted a two- to three-fold increased risk for anxiety in adulthood. However, the course of the different subtypes of anxiety disorders in adolescence tended to vary. That is, adolescent simple phobia predicted primarily simple phobia in adulthood, and social phobia predicted primarily social phobia. In contrast, overanxious, generalized anxiety, and panic disorder had a nonspecific course.

In summary, findings of Keller et al. (1992) and Cohen et al. (1993) have shown anxiety disorders to have a stable course, whereas that of Last et al. (1996) failed to support the stability of these disorders. Inconsistent findings are difficult to interpret given different characteristics of these studies such as differences in sample and time interval between the index and follow-up interviews.

In order to enhance our knowledge on the course of anxiety disorders in adolescents, the main aims of this article were to examine the course and outcome of anxiety disorders, and to examine factors related to their stability using data of the Bremen Adolescent Study; this project is a longitudinal school-based study of psychiatric disorders among 12–17 year olds (Essau, 2000; Essau et al., 1999a, Essau et al., 1999b, Essau et al., 2000). The specific aims of the present study were to address the following questions: (1) How many adolescents who met the diagnosis of anxiety at the index interview also met these disorders at the follow-up interview? (2) How many of the anxious adolescents at T1 developed another disorders at T2? (3) What are the factors which predict the stability of anxiety disorders?