Quantitative evaluation of multiple treatment regimens for treatment-resistant depression

This study aims to quantitatively evaluate the efficacy and safety of various treatment regimens for treatment-resistant depression (TRD) across oral, intravenous, and intranasal routes to inform clinical guidelines.

A systematic review identified randomized controlled trials on TRD, with efficacy measured by changes in the Montgomery-Åsberg Depression Rating Scale (MADRS). We developed pharmacodynamic and covariate models for different administration routes, using Monte Carlo simulations to estimate efficacy distribution. Dropout and adverse event-related dropout rates were analyzed via single-arm meta-analysis.

Involving 22 studies with 56 treatment arms and 3059 patients, our findings suggest combination therapies outperform monotherapy, achieving an additional 6.5% reduction in MADRS scores over 12 weeks. The most effective combinations were olanzapine with fluoxetine and quetiapine with selective serotonin reuptake inhibitors/ selective serotonin and norepinephrine reuptake inhibitors. Injectable treatments, particularly ayahuasca, produced rapid effects, with a 77% reduction in MADRS scores at 15 days. Intranasal treatments reached efficacy sooner than oral ones, with 28-day efficacy similar to the 12-week efficacy of the olanzapine-fluoxetine combination. Dropout rates due to adverse events were similar across methods (4.5%-5.2%), but total dropouts were highest for oral (17.9%) and lowest for intranasal routes (10.6%). Additionally, there was considerable variation in the incidence of headache, dizziness, and nausea across different administration routes.

The quantitative evaluation of 22 TRD treatments illuminates key pharmacodynamic parameters, bolstering the development of clinical guidelines and aiding the design of clinical trials and medical decision-making.