Introduction: The purpose of this study was to examine whether the combination of atypical and typical antipsychotic medications is related with metabolism and cognitive functions in the same manner and degree as taking medications of one kind only, i.e. atypical or typical.Material and methods: The participants of the study comprised of 91 adults with diagnosed mental illness (F-20-F69). The participants were divided into groups on the basis of the kind of administered medications: T+A (typical and atypical medications), A (atypical medications), T (typical medications), P (antidepressants, sedatives, normothymic/antiepileptic drugs). In the study, Short Test of Mental Status (STMS), Verbal Fluency Test (VFT), Rey Auditory Verbal Learning Test (RAVLT) were used for the purpose of examining cognitive functions.Results: The kind of antipsychotic medications taken by the patients did not differentiate the group in relation to BMI (p<0.13), nor in relation to the level of general cognitive function (p<0.72) or verbal fluency (p<0.34). Both atypical antipsychotic medications and the combination of atypical and typical medications were related to the occurrence of abdominal obesity (p<0.01). An increase in waist circumference decreased an ability of abstract reasoning (p<0.005). When it comes to the body mass index, waist circumference negatively correlated with the delayed memory (p< 0.03, p<0.004).Discussion: Both the combination of atypical and typical antipsychotic medications and atypical medications are associated with the occurrence of abdominal obesity. The deposition of fat tissue in the abdomen negatively correlated with an ability to learn.Conclusions: The future studies might explain the interactions between antipsychotic medications, obesity and cognitive function.