Neurophysiological markers of depression detection and severity prediction in first-episode major depressive disorder

Sex-specific effects of subchronic NMDA receptor antagonist MK-801 treatment on hippocampal gamma oscillations

N-methyl-D-aspartate (NMDA) receptor antagonists are widely used to pharmacologically model schizophrenia and have been recently established in the treatment of treatment-resistant major depression demonstrating that the pharmacology of this substance class is complex. Cortical gamma oscillations, a rhythmic neuronal activity associated with cognitive processes, are increased in schizophrenia and deteriorated in depressive disorders and are increasingly used as biomarker in these neuropsychiatric diseases. The opposite use of NMDA receptor antagonists in schizophrenia and depression raises the question how their effects are in accordance with the observed disease pathophysiology and if these effects show a consequent sex-specificity. In this study in rats, we investigated the effects of subchronic (14 days) intraperitoneal injections of the NMDA receptor antagonist MK-801 at a subanesthetic daily dose of 0.2 mg/kg on the behavioral phenotype of adult female and male rats and on pharmacologically induced gamma oscillations measured ex vivo from the hippocampus. We found that MK-801 treatment leads to impaired recognition memory in the novel object recognition test, increased stereotypic behavior and reduced grooming, predominantly in female rats. MK-801 also increased the peak power of hippocampal gamma oscillations induced by kainate or acetylcholine only in female rats, without affecting the peak frequency of the oscillations. The findings indicate that blockade of NMDA receptors enhances gamma oscillations predominantly in female rats and this effect is associated with behavioral changes in females. The results are in accordance with clinical electrophysiological findings and highlight the importance of hippocampal gamma oscillations as a biomarker in schizophrenia and depression.

Adjunctive cariprazine as a novel effective strategy for treating major depressive disorder: A systematic review and meta-analysis

BACKGROUND

Cariprazine has been approved by the Food and Drug Administration for treating bipolar depression and as an adjunctive treatment for Major Depressive Disorder (MDD). However, it remains unclear about its pharmacological efficacy in treating MDD. Therefore, a meta-analysis was conducted to investigate the adjunctive use of cariprazine in MDD.

METHODS

Electronic databases were searched for eligible studies evaluating the efficacy and safety of cariprazine in patients with MDD up to November 15, 2023. The changes in Montgomery-Asberg Depression Rating Scale (MADRS) score and incidence of adverse events (AEs), which represents of efficacy and tolerability, are considered as the main outcomes.

RESULTS

A total of 3066 patients with MDD included in all across 5 RCTs. With regard to MADRS score, cariprazine group showed better results than control group (SMD = -0.12, 95% CI -0.19 to -0.04, P = 0.002, 5 RCTs, n = 3066). Cariprazine, meanwhile, improved the MADRS response (RR = 1.19, 95% CI 1.08 to 1.31, P = 0.0004, 5 RCTs, n = 3066). For safety outcomes, statistical difference was observed in AEs (RR = 1.26, 95% CI 1.18 to 1.35, P < 0.00001, 5 RCTs, n = 3077). The suicide ideation and SAEs showed no statistical difference between two groups.

CONCLUSION

Cariprazine demonstrated antidepressant effect as an augmentation therapy in treating MDD. Meanwhile, the tolerability of it was acceptable as an adjunctive treatment. However, studies with larger sample sizes are still needed to explore the optimal dosage.