141 - Antipsychotic induced weight gain

Antipsychotic-induced weight gain

Schizophrenia and related psychoses CHAPTER 1 Antipsychotic-­induced weight gain Weight gain is a common adverse effect of antipsychotic medication.1 This may reflect interference with the homeostatic control of appetite and metabolism, leading to increased food intake and reduced energy expenditure, although the various mechanisms involved are not well understood.2–4 Factors such as 5HT2C antagonism, H1 antagonism, D2 antagonism and increased serum leptin (leading to leptin desensitisation)5–7 are commonly implicated, as well as, possibly, effects on gut microbiota.8–11 The risk of weight gain appears to be related to clinical response12,13 (although the association may be too small to be clinically important)14 and may have a genetic basis.15 Weight gain may be more pronounced in antipsychotic-­naïve patients and during the early stages of the treatment of psychotic illness16–18 and women may be at greater risk than men.19,20 Almost all available antipsychotic medications have been associated with weight gain,16 although the mean gain in body weight varies substantially between the medications. There is also marked inter-­individual variation among those treated, with some losing weight, some gaining no weight and some gaining a great deal of weight. Thus, knowledge of the mean increase in weight reported for a particular medication may not be a helpful predictor of how much weight an individual might gain. Assessment of the relative liability for weight gain of different antipsychotic medications is based largely on short-­term studies. Notwithstanding these limitations, the results of indirect and direct meta-­analyses suggest that these medications can be clustered into three groups based on their relative risk of weight gain (Table 1.31).21,22 Table 1.31  Risk/extent of antipsychotic-­induced weight gain (drugs in alphabetical order).23–26 Risk/extent of weight gain Drug High Clozapine Olanzapine Moderate Chlorpromazine FGAs* Iloperidone Haloperidol Quetiapine Paliperidone Risperidone Sertindole (Continued)