Effect of add-on alpha lipoic acid on psychopathology in patients with treatment-resistant schizophrenia: a pilot randomized double-blind placebo-controlled trial

RATIONALE: Alpha lipoic acid is known to reverse NMDA receptor hypofunction in addition to dopamine receptor blockade activity. It also enhances neurotrophic factors and has antioxidant potential. These properties combined together may be beneficial for treatment-resistant schizophrenia (TRS). OBJECTIVES: This study evaluates the effect of alpha lipoic acid (ALA) on psychopathological scores (positive, negative, cognitive), neurotrophic factors and oxidative stress in TRS. METHODS: A pilot randomized double-blind placebo-controlled parallel design trial was conducted in 20 patients with TRS. After initial screening, participants were randomized into test (add-on ALA) and control (add-on placebo) groups. After recruitment, clinical evaluations with scale for assessment of positive symptoms and negative symptoms (SAPS and SANS), schizophrenia cognitive rating scale (SCoRS), UKU side effect rating scale were done. Serum levels of BDNF, MDA, and GSH were estimated. Patients were followed up for 8 weeks, and clinical and biochemical evaluations were repeated. Adherence to medication was evaluated at follow-up. RESULTS: A significantly greater improvement was found in SANS score in the test group when compared to control (Mann–Whitney U = 17.0; p = 0.021), whereas there was no significant improvement in SAPS score (Mann–Whitney U = 41.5; p = 0.780). A significant increase in BDNF levels was observed in the control group when compared to ALA (U = 20.0; p = 0.041). No significant differences were found between the test and control groups in serum MDA (U = 30.0; p = 0.221), serum GSH (U = 40.0; p = 0.683), and medication adherence rating scale (MARS) scores (U = 44.0; p = 0.934). CONCLUSIONS: ALA supplementation improved psychopathology and decreased oxidative stress in patients with TRS. This study thus shows the potential of adjunctive ALA in TRS. TRIAL REGISTRATION: The study was prospectively registered in Clinical Trial Registry of India (CTRI/2020/03/023707 dated 02.03.2020).