Metabolic syndrome is a group of concomitant disorders that increase the risk of heart attack, stroke and diabetes. In Europe metabolic syndrome is defined using the IDF (International Diabetes Federation) criteria. According to these criteria, metabolic syndrome is the co-occurrence of abdominal (central, visceral) obesity, defined as abdomen circumference ≥80 cm in women and ≥94 cm in men plus two out of four criteria: 1) level of triglycerides >1.7 mmol/l (150 mg/dl) or treatment of triglyceridemia; 2) level of HDL cholesterol <1.0 mmol/l (40 mg/dl) in men and <1.3 mmol/l (50 mg/dl) in women or treatment of this disorder; 3) systolic blood pressure ≥130 mm Hg or diastolic blood pressure ≥85 mm Hg or treatment of previously diagnosed hypertension; 4) fasting plasma glucose ≥5.6 mmol/l (100 mg/dl) or treatment of previously diagnosed type 2 diabetes. Metabolic syndrome is 2–3 times more frequent in patients receiving antipsychotics. The presence of metabolic syndrome is associated with a 2–3 fold increased risk of death due to cardiovascular complications. Almost all antipsychotics increase the risk of metabolic syndrome and the greatest risk is that due to the most effective drugs (clozapine, olanzapine). In most cases metabolic complications of antipsychotic treatment is treatment-induced increase of appetite and weight gain, while for certain medications these complications may develop as a direct effect of antipsychotics. The vast majority of patients do not receive a proper treatment of metabolic disorders. Available treatment options for drug-induced weight gain are not very effective and very rarely used.