Robin Murray1, Marta Di Forti2, Evangelos Vassos2, Harriet Quicgley1, Antonella Trotta2, Diego Quattrone2, Victoria Rodrigues1, Craig Morgan; 1Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, London, 2MRC Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, De Crespigny Park, London, 3Society and Mental Health Research Group, Health Service and Population Research Department, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
Background. The main attempt to prevent the development of psychosis has been through clinics for people at clinical high risk. Such an approach is useful for research but can never reach the majority of individuals who will become psychotic. Biological markers could be used to identify individuals with unusual vulnerabilities e.g. those with copy number variations. However, identifying those with such markers is unlikely to impact on the majority of cases, and as yet no useful interventions are available. How therefore to prevent psychosis? Methods Data will be presented from 3 studies of first onset psychosis which used similar methods of ascertainment and assessment of cases and controls across 16 sites in 5 European countries. Results The polygenic risk score accounted for the greatest variance in caseness; those with scores in the highest quintile were 7 times more likely to be a psychotic case than those in those lowest quintile. Attributable fraction analyses indicated that if no one was exposed to child abuse and use of high potency cannabis, then 16% and 24% respectively of psychosis in South-London could be prevented. There are differences in the incidence of psychosis between Northern and Southern Europe. Conclusions Similarly to preventive approaches for hypertension or obesity where members of the general population are encouraged to take exercise and reduce their calorie intake, attempts should be made to influence society’s patterns of consumption of high-potency cannabis and educate them on impact of childhood abuse in a bid to prevent development of psychosis.
