1. ¹Neurobiology Research Unit, Center for Integrated Molecular Brain Imaging, University Hospital Rigshospitalet, Copenhagen, Denmark
2. ²Center for Neuropsychiatric Schizophrenia Research, University of Copenhagen, Psychiatric University Centre Glostrup, Copenhagen, Denmark
3. ³Center for Neuropsychiatric Schizophrenia Research, University of Copenhagen, Bispebjerg Hospital, Copenhagen, Denmark
4. ⁴Danish Center for Magnetic Resonance Imaging, Center for Integrated Molecular Brain Imaging, Hvidovre University Hospital, Copenhagen, Denmark
5. ⁵PET and Cyclotron Unit, University Hospital Rigshospitalet, Copenhagen, Denmark

Correspondence: Dr D Erritzoe, Neurobiology Research Unit 9201, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, Copenhagen 2100, Denmark. Tel: 0045 2618 1392; Fax: 0045 3545 6713; E-mail: david@nru.dk

Received 6 August 2007; Revised 31 October 2007; Accepted 7 November 2007; Published online 20 February 2008.

Abstract

The serotonin 5-HT_2A receptor is suspected to be involved in a number of psychiatric disorders, including schizophrenia. In particular, atypical antipsychotics have antagonistic effects on the 5-HT_2A receptors, supporting a specific role of the 5-HT_2A receptor in the pathophysiology of this disease. The aim of this study is to investigate cortical and subcortical 5-HT_2A binding in neuroleptic-naive schizophrenic patients. Fifteen neuroleptic-naive patients diagnosed with schizophrenia (age 27.54.5 years), 11 men and 4 women, and 15 healthy control subjects matched for age (28.55.7 years) and gender underwent a 40 min positron emission tomography (PET) study using the 5-HT_2A antagonist, [¹⁸F]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 (BP_p) was used as the outcome measure. No significant difference was seen in cortical receptor distribution between patients and controls. An increase in 5-HT_2A receptor binding in the caudate nucleus was detected in the group of schizophrenic patients (0.70.1) when compared to the healthy controls (0.50.3) (p=0.02). Our results confirm other in vivo findings of no difference in cortical 5-HT_2A receptor binding between first-episode antipsychotic-naive schizophrenic patients and age- and gender-matched healthy control subjects. However, a preliminary finding of increased 5-HT_2A binding in the caudate nucleus requires further investigation to explore the relation of subcortical and cortical 5-HT_2A receptor binding.