Serotonin transporter gene polymorphisms and auditory hallucinations in psychosis

To study the role of the serotonin transporter gene (SLC6A4) in the emotional processing of auditory hallucinations can be particularly important to better understand the pathophysiology of auditory hallucinations. Moreover, a poly-morphism located in this gene (5-HTTLPR) has been previously associated with different disorders related to altered emotional responses. The aim of this study was to evaluate the relationship between different polymorphisms of the SLC6A4 gene and different aspects of auditory hallucinations in schizophrenic patients, with a special consideration toward the emotional response to auditory hallucinations.

Two samples of 224 patients with auditory hallucinations and 346 healthy subjects were studied. AH were assessed in patients through the PSYRATS scale for auditory hallucinations. Several polymorphisms located within the SLC6A4 gene were analysed through case-control comparisons as well as association analyses with different parameters of auditory hallucinations.

No differences were found between patients and controls for any of the analysed polymorphisms (p > 0.05). However, the evaluation of auditory hallucinations parameters showed that the low expressing alleles of the 5-HTTLPR polymorphism were associated with higher levels of intensity of the distress caused by auditory hallucinations (p = 0.049 corrected for the item 'intensity of distress'). There was also a trend with the parameter disruption (p = 0.06 corrected). These two items of the PSYRATS scale are directly related to the emotional dimension of auditory hallucinations. In contrast, we did not observe any association with items related to other dimensions of auditory hallucinations.

Our results support a possible role of the serotonin transporter in the emotional response to auditory hallucinations.