Cluster C personality disorder impedes alleviation of symptoms in major depression

Background: We investigated whether cluster C personality disorder (CPD) is associated with recovery from depression. Methods: The study design was observational. Diagnoses of major depression (MD) and CPD were confirmed by means of the Structured Clinical Interview for DSM-III-R (SCID-I, -II). Changes in symptom scales in 52 patients with MD and CPD were compared with changes in 65 patients with MD alone over a 6-month follow-up period. Results: On the Hamilton Depression Rating Scale and Beck Depression Inventory (BDI) scales, recovery of patients with MD and comorbid CPD was inferior to recovery of patients with MD alone. Findings were similar in relation to several other symptom scales. Of those with MD alone 54% had recovered from their depression, but only 16% of those with CPD and MD (BDI score <10 on follow-up). Logistic regression analysis revealed an independent association between lack of recovery and presence of CPD (OR 7.5, 95% CI 2.6–22.2). Limitations: Study design was observational. Conclusion: The presence of CPD hinders alleviation of depressive symptoms in major depression.