Clozapine research standards in former USSR states: A systematic review of quality issues with recommendations for future harmonization with modern research standards.

Objective: As access to an essential part of clozapine research from the former Union of Soviet Socialist Republics (USSR) states is very limited, quality aspects have not gained attention so far, and harmonization with modern research standards remains unclear.

Methods: We performed a systematic search in PubMed, Embase and scientific indexes from former USSR states for articles published in Russian language till January 2023 (PROSPERO Reg. Number CRD42023386737) and assessed their quality using the modified Strengthening the reporting of observational studies in epidemiology (STROBE)-Checklist. We compared quality aspects for papers published before and after 2000.

Results: A total of 60 papers were considered. Conflicts of interests and funding sources were reported in 5 and 3 (8 % and 5 %) studies respectively; ethical approval was warranted in two studies (3 %). Statistical analysis was performed in 57 (95 %) studies, but statistical methods were described in 21 (35 %) studies. When comparing studies before and after 2000, there was a trend towards improvement for several aspects, with the only significant differences being the objectives' specification (43 vs 83 %, p < 0.003) and the reporting of statistical methodology (0.0 vs 46 %, p < 0.001), which were more frequently available in papers after 2000.

Conclusions: Clozapine papers in Russian language suffered from severe methodological drawbacks limiting generalizability. Changes regarding standardization, transparency, ethics, and good scientific practice are urgently required. Using reporting checklists and predefining protocols are the first steps towards quality upgrade and accelerate the integration of science from the former USSR states into the world scientific system.