Introduction:
Suspiciousness (paranoid thinking) and feelings of alienation (psychotic experiences) are key symptoms of psychotic disorders like schizophrenia. However, they is also evidence that subclinical psychotic-like experiences are also distributed in the general population and thus are continuous phenomena (e.g. van Os et al., 2009). In patients, there is also evidence that those clinical measures are associated with changes in brain structure. In our study, we wanted to test if similar associations can also be found in the healthy spectrum.
Methods:
In a sample of 672 healthy subjects (424 female, mean age = 32.51 years, SD = 12.23 years) from the cohort study of the DFG FOR2107, we assessed subclinical psychotic-like symptoms with the symptom-checklist-90R (SCL90R) scales “schizotypal signs” and “nuclear schizophrenia symptoms” (Rössler et al., 2007). Based on high resolution T1-weighted MRI, we analysed voxel- and surfaced-based brain structural parameters with SPM12 and CAT12.
Results:
We found a positive correlation of schizophrenia nuclear symptoms with the volume in the left superior parietal lobule and the precuneus, and a positive correlation of schizotypal signs with the volume of the left and right precentral gyrus (all p < 0.001, FWE-corrected). We further associated the gyrification in the insula and precuneus with the level of both schizotypal signs and nuclear schizophrenia symptoms (p < 0.001, uncorrected). Our results show that brain structural parameters in areas relevant for schizophrenia are associated with subclinical psychotic experiences.
Conclusion:
Our results show that brain structure in areas relevant for schizophrenia is associated with subclinical psychotic experiences. This endorses a dimensional, continuous model of neural correlates of symptoms of the psychotic spectrum and highlights the importance of resilience factors that protects from the progression into psychosis in spite of psychotic-like traits.
