Metabolic syndrome can contribute to significant morbidity and premature mortality and should be accounted for in the treatment of mental disorders. Patients with schizophrenia are at risk of undetected somatic comorbidity. Patients with schizophrenia have metabolically unfavorable body composition, comprising abdominal obesity, high fat percentage and low muscle mass, leading to increased risk of metabolic and cardiovascular diseases. Smoking, poor diet, reduced physical activity and alcohol or drug abuse are prevalent in people with schizophrenia and contribute to the overall cardiovascular disease risk. Side effects of antipsychotics may cause diagnostic problems in deciding regarding the origin of particular symptoms (somatic illness vs. side effects) during treatment of psychotic disorders. Bearing in mind frequent comorbidity between of psychotic and somatic disorders, early recognition of such comorbidity is important, as well as the selection of antipsychotics. The aim of this article is to report a case of changes in values of cholesterol and tryglicerides after weight loss, during treatment with aripiprazole in a patient with schizophrenia. This case report emphasizes the importance of regular monitoring of values of cholesterol and tryglicerides during treatment with antipsychotics.