The comorbidity of anxiety and depression

This study explored the effect of comorbid anxiety disorders in patients admitted to an inpatient specialist Mood Disorders Unit for the treatment of a primary major depressive episode.

Subjects were assessed on admission and discharge. DSM-III-R diagnoses for major depression and anxiety disorders were established using CIDI-Auto; comorbid anxiety disorders were coexistent in time with the major depression, with both conditions meeting diagnostic criteria at the time of assessment. Severity of illness was assessed using the Hamilton Depression/Melancholia Scale, the revised Hamilton Anxiety Scale and the revised Beck Depression Inventory.

For the analysis, the study cohort was divided into three groups: depression alone (n = 33), one comorbid anxiety disorder (n = 15), and two or more comorbid anxiety disorders (n = 24). No particular anxiety disorder predominated. Interestingly, the presence or absence of comorbid anxiety with severe major depression made no significant difference to treatment choice or outcome results. Specifically, there was no significant difference between the three groups in the utilisation of electroconvulsive therapy and pharmacotherapy (including antidepressants, benzodiazepines and neuroleptics); all subjects improved significantly on both depression and anxiety ratings, and length of inpatient stay did not vary significantly between the three groups.

The existence of comorbid anxiety disorders in those patients who presented for treatment of a primary major depressive episode did not significantly effect choice of treatment or treatment outcome, suggesting that there is a close interrelationship between the two conditions.