Interaction between family history and subject status

<p>Schizophrenia patients obtained lower IQ scores (mean=94.69 [93.49-95.88]) compared to controls (mean=110.17 [108.88-111.46]) with intermediate scores in the siblings of schizophrenia patients (mean=103.06 [101.95-104.17]). A significant interaction was found between family history of psychiatric disorder and clinical status (F(2,1086.87)=4.17; p=.016). Patients with a positive family history of psychiatric disorder obtained higher intelligence scores compared to patients with no family history (mean IQ scores are 95.52 [94.08-96.95] and 92.72 [90.57-94.88], respectively) with an opposite effect in controls (mean IQ scores are 108.71 [106.67-110.76] and 111.19 [109.52-112.85], respectively). No significant difference was found between siblings of schizophrenia patients with or without a positive family history (mean IQ scores are 102.98 [101.65-104.30] and 103.24 [101.19-105.29], respectively).