Cortical and subcortical 5-HT2A receptor binding in neuroleptic-naive first-episode schizophrenic patients

The serotonin 5-HT2A receptor is suspected to be involved in a number of psychiatric disorders, including schizophrenia. In particular, atypical antipsychotics have antagonistic effects on the 5-HT2A receptors, supporting a specific role of the 5-HT2A receptor in the pathophysiology of this disease. The aim of this study is to investigate cortical and subcortical 5-HT2A binding in neuroleptic-naive schizophrenic patients. Fifteen neuroleptic-naive patients diagnosed with schizophrenia (age 27.5 +/- 4.5 years), 11 men and 4 women, and 15 healthy control subjects matched for age (28.5 +/- 5.7 years) and gender underwent a 40 min positron emission tomography (PET) study using the 5-HT2A antagonist, [F-18] altanserin, as a radioligand. PET images were co-registered to 3 T magnetic resonance images (MRIs) for each individual subject, and ROIs were applied automatically onto the individual MRIs and PET images. The cerebellum was used as a reference region. The binding potential of specific tracer binding (BPP) was used as the outcome measure. No significant difference was seen in cortical receptor distribution between patients and controls. An increase in 5-HT2A receptor binding in the caudate nucleus was detected in the group of schizophrenic patients (0.7 +/- 0.1) when compared to the healthy controls (0.5 +/- 0.3) (p = 0.02). Our results confirm other in vivo findings of no difference in cortical 5-HT2A receptor binding between first-episode antipsychotic-naive schizophrenic patients and age- and gender-matched healthy control subjects. However, a preliminary finding of increased 5-HT2A binding in the caudate nucleus requires further investigation to explore the relation of subcortical and cortical 5-HT2A receptor binding.