Hostility changes following antidepressant treatment: relationship to stress and negative thinking.

It is unclear whether changes in hostility following treatment are primarily related to improvement in depressive symptoms or are also closely associated with reductions in negative thinking or perceived stress. We evaluated 94 outpatients with major depression before and after eight weeks of fluoxetine treatment by administering the Symptom Questionnaire (SQ) Hostility Scale, the Hamilton Rating Scale for Depression (HAM-D), the Cognitions Questionnaire (CQ) and the Perceived Stress Scale (PSS). We observed significant elevations in scores on these questionnaires in depressed patients as compared to normal controls. Following treatment with fluoxetine, there was a statistically significant reduction in scores on all four questionnaires. We observed that changes in SQ Hostility were significantly positively related to changes in both depression severity and perceived stress, with these relationships remaining significant after adjusting for gender and baseline SQ Hostility. The relationship between SQ Hostility changes and reductions in negative thinking became significant only after adjusting for gender and baseline SQ hostility. Our results suggest that the marked decrease in hostility following antidepressant treatment is related to a reduction in depressive symptoms, stress levels and negative thinking.