The highly complex structure of the human brain is strongly shaped by genetic influences1. Subcortical brain regions form circuits with cortical areas to coordinate movement2, learning, memory3 and motivation4, and altered circuits can lead to abnormal behaviour and disease2. To investigate how common genetic variants affect the structure of these brain regions, here we conduct genome-wide association studies of the volumes of seven subcortical regions and the intracranial volume derived from magnetic resonance images of 30,717 individuals from 50 cohorts. We identify five novel genetic variants influencing the volumes of the putamen and caudate nucleus. We also find stronger evidence for three loci with previously established influences on hippocampal volume5 and intracranial volume6. These variants show specific volumetric effects on brain structures rather than global effects across structures. The strongest effects were found for the putamen, where a novel intergenic locus with replicable influence on volume (rs945270; P = 1.08 × 10−33; 0.52% variance explained) showed evidence of altering the expression of the KTN1 gene in both brain and blood tissue. Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance and vesicle transport. Identification of these genetic variants provides insight into the causes of variability inhuman brain development, and may help to determine mechanisms of neuropsychiatric dysfunction.

Antipsychotic-induced weight gain is an important issue in the treatment of psychotic illnesses, and affects 80% of individuals being treated with antipsychotic drugs. However, the true dimension of weight gain and many accepted 'facts' in this area remain unclear as most research has been conducted in short-term trials and has included individuals receiving prolonged antipsychotic treatment. This review aims to systematically and critically review the evidence on weight gain induced by the two leading second-generation antipsychotics (olanzapine and risperidone) and the most widely researched first-generation antipsychotic (haloperidol) in patients with chronic and first-episode psychotic disorders. Weight gain was 3- to 4-fold greater in studies that included young patients with limited previous exposure to antipsychotic agents in both short-term studies (7.1-9.2 kg for olanzapine, 4.0-5.6 kg for risperidone and 2.6-3.8 kg for haloperidol vs 1.8-5.4 kg, 1.0-2.3 kg and 0.01-1.4 kg, respectively, in studies that included patients with chronic psychotic disorders) and long-term trials (10.2-15.4 kg for olanzapine, 6.6-8.9 kg for risperidone and 4.0-9.7 kg for haloperidol vs 2.0-6.2 kg, 0.4-3.9 kg and -0.7 to 0.4 kg, respectively). The same disparity was observed regarding the proportion of patients increasing their baseline weight by > or =7% (the cut-off for clinically significant weight gain). Recent studies carried out in young patients with first-episode psychosis (FEP), along with methodological artefacts in studies of chronic populations, suggest that the magnitude of weight gain reported by much of the literature could in fact be an underestimation of the true magnitude of this adverse effect. Although antipsychotics present idiosyncratic patterns of weight gain, they may also generate similar absolute gains.

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