Weight gain associated with the α_2a‐adrenergic receptor −1291 C/G polymorphism and olanzapine treatment

<jats:title>Abstract</jats:title><jats:p>Weight gain can be an adverse effect of antipsychotics and is an important factor for long‐term health and treatment compliance. Many reports have shown that the α<jats:sub>2</jats:sub>‐adrenergic receptor may be related to eating behaviors or lipolytic activities, both associated with body weight change. We hypothesized that there might be a relationship between the α<jats:sub>2a</jats:sub>‐adrenergic receptor −1291 C/G polymorphism and olanzapine‐induced weight gain. A group of 62 Korean schizophrenic patients participated in a study; weight and height measurements were obtained prior to starting olanzapine and measured again after long‐term treatment. Genotyping for the −1291 C/G polymorphism was performed on all participants. Body weight changes from baseline to endpoint were significantly associated with genotypes (<jats:italic>P</jats:italic> = 0.028). The frequency of the G allele was significantly higher in subjects who had severe weight gain (defined as a more than 10% weight gain from baseline) compared to subjects who did not have extreme weight gain (less than 10% weight gain from baseline) (X<jats:sup>2</jats:sup> = 6.120, <jats:italic>P</jats:italic> = 0.013; OR = 2.58, 95% CI = 1.21–5.51). Therefore, the findings from this study support a relationship between the −1291 C/G polymorphism of the α<jats:sub>2a</jats:sub>‐adrenergic receptor and weight gain in Korean schizophrenic patients receiving olanzapine treatment. © 2006 Wiley‐Liss, Inc.</jats:p>