Serum brain-derived neurotrophic factor level and its relation with cannabis use disorder and schizophrenia: A cross-sectional exploratory study in patients at a tertiary care hospital.

Background: Brain-derived neurotrophic factor (BDNF) has considerable relevance in neural growth and differentiation. It has been evaluated as a biomarker for individuals with various psychiatric disorders such as substance-related disorders and psychotic disorders.

Objective: The present study explored differences in the levels of BDNF (in serum) among subjects using cannabis (with and without schizophrenia).

Methods: This cross-sectional observational study compared the serum BDNF level in male subjects aged 18-45 years. Four groups of 20 subjects each were included: individuals with tobacco use disorder only, patients having schizophrenia, patients with cannabis use disorder, and finally patients with comorbid cannabis use disorder and schizophrenia.

Results: The BDNF levels were found to be significantly different across the four groups. The BDNF levels in subjects with concurrent schizophrenia and cannabis use disorder were higher than each of the other three groups (cannabis use disorder, schizophrenia, and tobacco use disorder only).

Conclusion: We find that BDNF may be higher when cannabis use disorder and schizophrenia co-occur, as compared to either of the conditions alone. The findings should be interpreted with caution due to the low sample size and potential confounders.