Sameer Jauhar1, Matthew M Nour1, Mattia Veronese1, Maria Rogdaki1,2,3, Federico Turkheimer1, Alice Egerton1, Janmes Stone1, Philip McGuire1, Oliver D Howes1,2,3; 1King's College, London, 2Psychiatric Imaging Group MRC London Institute of Medical Sciences, Hammersmith Hospital, London, 3Institute of Clinical Sciences, Faculty of Medicine, Imperial College, Hammersmith Hospital, London
Studies suggest the presynaptic dopamine system is altered in schizophrenia, meta-analytic evidence suggesting elevation in striatum. There are few studies examining whether these abnormalities are trans-diagnostic. Cross-sectional data also suggests nuances related to antipsychotic response, with elevated presynaptic dopamine synthesis capacity (DSC) in people with schizophrenia who respond to antipsychotics, and those resistant to antipsychotics have similar DSC to controls. In this oral presentation I will present data on people with first episode psychosis who underwent F-DOPA PET imaging (bipolar, n=22, schizophrenia n=16), scanned at onset of illness, predominantly free of antipsychotic medication (antipsychotic naïve or free n=32), a proportion of whom were involved in a subsequent study, examining baseline DSC and antipsychotic response (n=40, healthy controls, n=14). The aims were to ascertain whether elevated striatal DSC was associated with positive psychotic symptoms (using PANSS) at baseline, whether baseline striatal DSC was related to antipsychotic response, and if people could be stratified as responders/non-responders (d prior to antipsychotic treatment. We found elevated striatal DSC in bipolar psychosis and schizophrenia, compared to matched healthy controls (F2,57 = 6.80, P = .002), and in people experiencing a current psychotic episode, DSC was related to positive psychotic symptoms (n = 32, r = 0.52, P = .003). In the subsequent study we found an association between baseline striatal DSC and subsequent antipsychotic response (n=26, r=r=0.64, p<0.01), and that initial DSC discriminated at group level between responders, non-responders and healthy controls (F(2, 37)=7.9, p=0.001). I will then discuss the possible clinical utility of F-DOPA PET imaging in psychosis.
