There is substantial evidence suggesting that individual variability in antipsychotic treatment response could be genetically determined. Disrupted-in-Schizophrenia 1 (DISC1) gene has been previously associated to the illness and to treatment response in a sample of patients suffering from psychosis. However, there is a lack of studies on the effect of DISC1 on treatment response in samples of first episode psychosis.

The aim of this study was to explore the relation between variations in DISC1 gene and treatment response to antipsychotics in a sample of drug-naïve patients with a first episode of psychosis.

Two hundred and twenty Caucasian drug-naive patients experiencing a first episode of non-affective psychosis were genotyped for rs821616 (Ser704Cys), rs6675281 (Leu607Phe) and rs1000731. Early (6 weeks) response to antipsychotic treatment was assessed with the Brief Psychiatric Rating Scale, the Scale for the Assessment of Positive Symptoms, and the Scale for the Assessment of Negative Symptoms. Other clinical and socio-demographic variables were recorded to eliminate potential confounding effects.

We found a significant association between rs1000731 and treatment response. Thus, those patients homozygous for the G allele of rs1000731 were more frequently non-responders, measured with SANS, after 6 weeks of treatment, than those carrying the A allele (X2 = 4.019; P = 0.032). Moreover, when analysing the clinical improvement longitudinally, we observed that those patients carrying the A allele for the rs1000731 presented a greater improvement in positive symptoms dimension (F = 8.905; P = 0.003).

Our results suggest a minor contribution to antipsychotic drug response of genetic alterations in the DISC1 gene.

The authors have not supplied their declaration of competing interest.