Frequency of abnormal correlation between leptin and the body mass index during first and second generation antipsychotic drug treatment

Abstract Background Leptin dysregulation has been implicated in the body weight gain and metabolic dysfunction observed with the second generation antipsychotic drugs (SGAD) olanzapine and clozapine. Methods This study quantified the frequency of subjects with abnormal correlation between leptin and the body mass index controlling for gender (defined as being out of the upper or lower 95% confidence interval in the regression line when combining each group with the drug-free subjects) after prolonged treatment with olanzapine ( n  = 126), clozapine ( n  = 62), first generation antiypsychotics ( n  = 91), other SGAD ( n  = 22), other psychotropic drugs ( n  = 65) and drug-free subjects ( n  = 229). Results None of the analysis was significant ( p  > 0.05). In fact, in 17 out of 20 comparisons, the drug-free group had numerically higher frequencies of outliers than the corresponding treatment group. There were 28 outliers (4.7% of the total sample). In agreement with previous studies, cross-sectional analysis did not report gross alterations in serum leptin levels during olanzapine or clozapine administration. Conclusions Longitudinal studies should focus on leptin regulation early on treatment, on the frequency of abnormal leptin receptor sensitivity and/or specific polymorphisms in the leptin allele and on several confounding factors in order to design personalized preventive and therapeutic measures.