The effects of aripiprazole on the subscales of the Kellner Symptom Questionnaire in treatment resistant depression

We have recently examined the efficacy of low-dose aripiprazole augmentation for major depressive disorder (MDD), with modest nonsignificant benefit found. In a secondary investigation, we examined whether aripiprazole resulted in improvement in four subscales (depression, anxiety, somatic symptoms, and hostility) of the Kellner Symptom Questionnaire (KSQ). We reanalyzed data from the main outcome study on 221 MDD patients with inadequate response to selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors. Patients were randomized, using the sequential parallel comparison design, into two 30-day phases, as follows: drug/drug (aripiprazole 2 mg/day in phase 1, aripiprazole 5 mg/day in phase 2), placebo/drug (placebo in phase 1, aripiprazole 2 mg/day in phase 2), or placebo/placebo (placebo in both phases). We examined changes in the KSQ score from baseline to endpoint on the basis of the subscaled Well-being and Reversal Distressed Anxiety Subscales. The score for the KSQ depression subscale improved from baseline to the end of follow-up, with a significant advantage for aripiprazole over placebo (P=0.0327). Although improvement was also observed in the anxiety and hostility scales, neither attained a significant advantage over placebo; no significant change was observed for the somatization subscale. Aripiprazole augmentation resulted in a significant improvement compared with placebo augmentation only in the depression subscale of the KSQ; however, the low dose may not have been enough to have an impact on the anxiety and hostility scales. The good tolerability of the low dose may have resulted in the absence of worsening of somatic symptoms. Prospective studies are needed to better characterize the impact of low doses of aripiprazole augmentation on different manifestations of MDD.