Genetic, trauma and drug use predictors of psychosis phenotypes and related psychopathology
Epidemiological and biological evidence indicates that cannabis use, especially daily use, is a risk factor contributing to the onset of Psychotic disorders. Importantly, cannabis use remains the most preventable risk factors for Psychotic disorders and while we know more about the patterns of use carrying the greatest risk, it remains unclear what makes some heavy users more susceptible to develop long-standing psychosis. While Psychotic disorders affect up to 3% of the population, minor psychotic symptoms and distressing paranoia in particular can be experienced by up to the 10% of the population. Paranoia, the unsubstantiated fear that others intend harm to the individual, has been associated with cannabis use and indeed with history of trauma and it is also one of the most frequent symptoms occurring in psychotic disorders, described in the Schizophrenia Commission, 2012 report, as the psychotic symptom carrying the greatest disability.
Therefore, investigating what explains why some heavy cannabis users remain well, while others develop paranoia and/or other psychiatric symptoms, and some a frank clinical disorder is a research question of global relevance. This especially, at a time when the spread of laws legalising cannabis use for medicinal and/or recreational purposes has lead to more relaxed attitudes towards cannabis, especially among young adults, who remain the largest consumers of cannabis in the population.
In our proposal, we plan to use the available socio-demographic data, the environmental context and newly built genetic scores to understand individual resilience and propensity to experience psychosis and its extent when exposed to trauma, cannabis or both.
Our findings, at a time when daily cannabis consumption might be prescribed for medicinal reasons, could also a) inform safe prescribing and b) identify groups that at particular risk, and should be given closer and specialist monitoring. Finally, the planned worked will provide data to begin to understand the neurobiology of psychosis and related phenotypes, in the context of heavy cannabis use and trauma and open the way towards integrated packages of care that address cannabis use, provide psychological intervention for trauma, and in the future might contribute to development of new drugs informed by the proposed genetic pathways work.