Altered cerebral perfusion measured by SPECT in relatives of patients withschizophrenia - Correlations with memory and P300

Background Genetic studies in schizophrenia are hampered by the complex het erogeneous clinical phenotype. Biological variables identified as trait mar kers of risk could clarify the mode of inheritance, define clinical subgrou ps and provide clues about aetiology. Aims To use single photon emission computed tomography (SPECT) to compare b rain perfusion maps in patients with schizophrenia (n=19), their asymptomat ic 'high-risk' relatives (n=36) and control subjects (n=34) and to examine the relationships between imaging, memory and P300; event-related potential . Method SPECT, memory tests and P300 recording were carried out. Results In the patients with schizophrenia and their relatives, perfusion w as reduced in left inferior prefrontal and anterior cingulate cortex and in creased bilaterally in a subcortical region. Perfusion significantly correl ated with verbal memory and P300 amplitude in left inferior prefrontal cort ex and with P300 latency in anterior cingulate cortex. Conclusions Medication-and symptom-free relatives bad altered regional perf usion intermediate between subjects with schizophrenia and controls. Impair ed perfusion, verbal memory and P300 appear to be related traits associated with an increased risk of illness. Declaration of interest Funded by the Medical Research Council and the Scot tish Office.