MAR 19, 2015 07:30 AM PDT

Keynote - The Environmental Causes of Schizophrenia - Developmental Hazards, Social Defeat, and Drug Abuse

Presented At Neuroscience
  • Professor of Psychiatric Research, Institute of Psychiatry, King's College London
      Robin Murray is Professor of Psychiatric Research at the Institute of Psychiatry, and indeed has spent most of his working life there apart from one year in the USA: fortunately the latter did not do him too much harm. His particular interest is in understanding the causes of psychosis, and he and his colleagues have contributed to the understanding that environmental factors such as obstetric events, heavy cannabis use and migration increase the risk of developing schizophrenia-like psychoses. He is also sees people with psychosis at the South London and Maudsley NHS Trust who are been referred from across the UK because they have not responded to treatment locally. He has written numerous articles, not all of the boring, and is the second most frequently cited psychiatrist outside the USA; he has supervised 52 PhDs and 35 of his students have become professors. He was elected a Fellow of the Royal Society in 2010 and received a knighthood in 2011.


    Traditional psychiatric textbooks describe schizophrenia as a clinical enigma of unknown aetiology. However, this is no longer true. We now know a great deal about the risk factors, or contributory causes, of schizophrenia. These can be roughly divided into two main types; those which result in a) aberrant neurodevelopment and b) those which cause dopamine dysregulation; both characteristic abnormalities found in schizophrenia. Genetic factors are, of course, pre-eminent. These will be discussed elsewhere. However, certain environmental factors have been consistently associated with schizophrenia. Some such as adverse obstetric events (e.g. prenatal infection, perinatal hypoxia) impair neurodevelopment. Others such as abuse of drugs such as amphetamines, cocaine and cannabis which increase striatal dopamine also increase risk. In recent years it has become clear that heavy use of high potency cannabis is responsible for a significant proportion of psychosis. Psychotogenic "legal highs" such as synthetic cannabinoids and cathinones are becoming an increasing cause of acute psychosis. A range of social adversities such as child abuse, adverse life events, migration/minority ethnicity appear also to facilitate dopamine dysregulation and consequent psychosis. Curiously, psychosis is more common in those born and brought up in large cities than in rural areas. Most recently, it has become clear that the incidence is much higher in cities in Northern countries such as UK and Holland than in both rural and urban areas in Spain and Italy. The exact reason(s) for these differences are unclear but speculation centres on social fragmentation and social isolation. The challenge for researchers is now to trace the pathogenic pathways from risk factors to psychosis.

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