Brief report
Symptom dimensions as predictors of the two-year course of depressive and anxiety disorders

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Abstract

Background

Because of the heterogeneity of known predictive factors, course-predictions for depression and anxiety are often unspecific. Therefore, it was investigated whether symptom-dimensions could be used as more specific course-predictors, on top of already known predictors, such as diagnosis and overall severity.

Methods

A sample of 992 subjects with depressive and/or anxiety disorders was followed in a 2-year prospective cohort study. Dimensions of the tripartite model (general distress, anhedonic depression and anxious arousal) were assessed at baseline. Diagnostic and course information were assessed at baseline and 2-year follow-up.

Results

Dimensional scores at baseline predicted diagnosis after two years and course-trajectories during follow-up. Increased general distress at baseline was associated with comorbid depression–anxiety at follow-up, increased anhedonic depression was associated with single depression and anxious arousal was associated with (comorbid) panic disorders at follow-up. Baseline general distress was associated with an unfavorable course in all patients. All associations were independent and added prognostic information on top of diagnosis and other predictive factors at baseline.

Limitations

Only prevalent patients were included at baseline and only three dimensions were measured

Conclusions

Symptom dimensions predict the future 2-year course of depression and anxiety. Importantly, the dimensions yield predictive information on top of diagnosis and other prognostic factors at baseline.

Introduction

Although several predictive factors are known, course predictions for depression and anxiety are usually unspecific. Depression is known to be episodic and sometimes chronic (± 20%) (e.g. Keller and Baker, 1992, Ormel et al., 1993, Piccinelli and Wilkinson, 1994), anxiety disorders are known to remit less often (e.g. Keller and Hanks, 1993, Pollack and Otto, 1997, Tiemens et al., 1996), and comorbid depression–anxiety is known to have a particularly unfavorable course (e.g. Shankman and Klein, 2002, Merikangas et al., 2003, Patten et al., 2010, Penninx et al., 2011). Other predictors of poor prognosis include old age (Penninx et al., 2011), young age-of-onset (Karlsson et al., 2008, Penninx et al., 2011), high severity (van Beljouw et al., 2010, Penninx et al., 2011) and long disorder duration (Conradi et al., 2008).

Still, prognosis varies between individuals with seemingly similar characteristics. To account for this heterogeneity, symptom-dimensions could be used as additional predictors, increasing homogeneity, circumventing comorbidity (Widiger and Samuel, 2005) and increasing statistical power (Goldberg, 2000, MacCallum et al., 2002). The tripartite model (Clark and Watson, 1991) describes well-validated common and specific dimensions for depression and anxiety (e.g. de Beurs et al., 2007, Keogh and Reidy, 2000, Marshall et al., 2003). The common dimension of ‘General distress (GD)’ covers psychological distress seen in both depression and anxiety and accounts for their comorbidity. The specific dimension of ‘Anhedonic depression (AD)’ covers depression-specific anhedonia/energy loss and ‘Anxious arousal (AA)’ covers anxiety/panic-specific somatic arousal. Each tripartite dimension was hypothesized to have specific prognostic value (Clark et al., 1994). Indeed, GD and AD were found to predict outcome of depression (Joiner and Lonigan, 2000, Lonigan et al., 2003) and generalized anxiety disorder (Chambers et al., 2004) and related dimensions made similar predictions (Geerts and Bouhuys, 1998, Clark et al., 2003). However, there were large methodological differences across studies and the AA-dimension was not often investigated. Moreover, anxiety and comorbid depression–anxiety patients were not accounted for in these studies, hampering the differentiation between the predictive abilities of GD, AD and AA. Importantly, the added value of dimensions on top of known predictors was not evaluated.

Therefore, we investigated the ability and added value of the tripartite dimensions in predicting the 2-year course and outcome of depression, anxiety and comorbid depression–anxiety in a large outpatient cohort (n = 992).

Section snippets

Participants

Participants came from the Netherlands Study of Depression and Anxiety (NESA), a large longitudinal cohort study (N = 2981) of participants with (n = 2329) or without (n = 652) a lifetime depressive/anxiety disorder (see Penninx et al. (2008) for details). Exclusion criteria were: not being fluent in Dutch or a psychotic, obsessive-compulsive, bipolar or severe addiction disorder. Ethical Review Boards of all participating universities approved the study-protocol. All participants signed informed

Baseline characteristics

Of the sample, 66.2% was female and the mean age was 42.5 years (s.d. = 12.3, see Table 1). Of the participants 227 (22.9%) had a single depressive disorder, 400 (40.3%) had single anxiety, and 365 (36.8%) had comorbid depression–anxiety. At baseline, mean age-at-onset was 20.9 (s.d. = 12.5), the mean percentage of months with symptomatology prior to baseline was 31.6 (s.d. = 20.1) and 384 participants (38.7%) used antidepressants. AD and AA were weakly correlated (r = 0.31) and GD was moderately

Discussion

The current study showed that common and specific dimensions of depression and anxiety, each add specific prognostic information on top of baseline DSM-diagnosis and other prognostic factors. Increased baseline GD was associated with increased odds of comorbid depression–anxiety at follow-up. Increased AD was associated with increased odds of single depression and increased AA was associated with increased odds of anxiety. In addition, increased GD predicted unfavourable course trajectories.

Role of funding source

The funding sources had no involvement in the study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.

Conflict of interest

The authors have no conflicts of interest to declare.

Acknowledgments

The infrastructure for the NESDA study (www.nesda.nl) is funded through the Geestkracht program of the Netherlands Organisation for Health Research and Development (Zon-Mw, grant number 10-000-1002) and is supported by participating universities and mental health care organizations (VU University Medical Center, GGZ inGeest, Arkin, Leiden University Medical Center, GGZ Rivierduinen, University Medical Center Groningen, Lentis, GGZ Friesland, GGZ Drenthe, Scientific Institute for Quality of

References (35)

  • L.A. Clark et al.

    Separate personality traits from states to predict depression

    Journal of Personality Disorders

    (2003)
  • M.E. den Hollander-Gijsman et al.

    Distinguishing between symptom-dimensions of depression and anxiety: an integrative approach

    Journal of Affective Disorders

    (2011)
  • T.E. Joiner et al.

    Tripartite model of depression and anxiety in youth psychiatric inpatients, relations with diagnostic status and future symptoms

    Journal of Clinical Child Psychology

    (2000)
  • L. Karlsson et al.

    One-year course and predictors of outcome of adolescent depression, a case–control study in Finland

    The Journal of Clinical Psychiatry

    (2008)
  • M.B. Keller et al.

    The clinical course of panic disorder and depression

    The Journal of Clinical Psychiatry

    (1992)
  • M.B. Keller et al.

    Course and outcome in panic disorder

    Progress in Neuro-Psychopharmacology & Biological Psychiatry

    (1993)
  • E. Keogh et al.

    Exploring the factor structure of the mood and anxiety symptom questionnaire (MASQ)

    Journal of Personality Assessment

    (2000)
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