Single-photon emission computed tomography (SPECT) is a valid method for measuring regional cerebral blood flow (rCBF). Recent studies regarding rCBF in patients with first episode psychosis (FEP) reported heterogeneous results, but were limited with small sample size. Neuroimaging can help us in setting the diagnosis of illness, as well as in following the progress and finding more effective treatment for psychotic disorders.

To compare, baseline alterations of the rCBF using SPECT with psychopathological status in FEP during acute phase.

To investigate the changes of rCBF in patients with FEP during acute phase.

We conducted a study on 40 drug – naïve patients with FEP at acute phase of illness during their hospitalization at Zagreb University hospital centre. The diagnosis was confirmed using diagnostic and statistical manual of mental disorders, fifth edition. rCBF was measured with SPECT and psychopathological status rated with the Positive and Negative Syndrome Scale.

Our findings showed moderate to severe parieto-temporal perfusion deficits, mild to moderate parieto-fronto-temporal perfusion deficits or borderline perfusion deficits in all but one patient.

Our results showed alteration in rCBF at the beginning of the illness that indicate a biological market of psychotic disorder.