Minocycline as adjunctive therapy for patients with unipolar psychotic depression: an open-label study

Approximately 25% of patients admitted to a hospital as a result of depression are actually suffering from psychotic depression. Psychotic symptoms can be present in patients with either unipolar depression or bipolar depression and can be difficult to treat. It was reported the second-generation tetracycline may exert potential antidepressant effects through its robust neuroprotective activities, which include neurogenesis, antioxidation, and anti-glutamate excitotoxicity, and may direct regulation of pro-inflammatory agents.

This was a 6-week, open-label study to evaluate the efficacy and safety of minocycline in combination with antidepressants in adult inpatients (n=25) diagnosed with major depression with psychotic features (psychotic depression) according to DSM-IV-TR. The primary endpoint was the change from baseline in the Hamilton Depression Rating Scale (HAM-D-21) score from baseline to week 6. Secondary endpoints were changes in the Brief Psychiatric Rating Scale (BPRS) and the Clinical Global Impression (CGI) Scale scores from baseline to week 6. Spontaneously reported adverse events were recorded.

The patients' average age was 46.9±10.2 years. Minocyline (150 mg/day) in combination with antidepressants (fulvoxamine, paroxetine, and sertraline) provided significant improvement in depression. Mean (± SD) HAM-D-21 was reduced to 6.7±1.9 at week 6 from a baseline value of 40.4±2.5. Significant improvement of psychotic symptoms (mean±SD) was indicated by the decrease in BPRS scores from baseline (63.3±8.7) to week 6 (4.6±2.4). No serious adverse events occurred.

These preliminary data suggest that minocycline in combination with antidepressants is effective and well tolerated in the treatment of unipolar psychotic depression. Further studies using larger, double-blind, parallel-group design are warranted to confirm these findings.