The Relationship between Cannabis Experience, Schizotypy, and Psychosis

A number of genetic and environmental vulnerabilities precipitate the clinical expression of schizophrenia and related psychotic disorders. Schizotypy and cannabis use are identified risk factors for the development of these disorders (Vaucher et al., 2018; Debanné et al., 2015). Schizotypy is defined as a set of personality characteristics and experiences that fall along the schizophrenia spectrum (Debbané et al., 2015). Individuals with schizotypy exhibit traits that are similar to, but less severe than, those of psychosis including marked differences in characteristic patterns of thinking, feeling, and behaving (Esterberg, 2010). An increase in severity of symptoms also correlates to impairment in social functioning, as seen by difficulty with socialization, occupational responsibilities, and relationships (Robustelli et al., 2017). The majority of individuals who report cannabis dependency also endorse elevated occurrence of psychotic symptoms and social impairment similar to those who have a clinical diagnosis of psychotic disorders (Guloksuz et al., 2019; Marconi et al., 2016; Schultz et al., 2019). Relationships between quantity of cannabis used (Solowij, 2018), age of initial use (Albertella et al., 2017; Raynal and Chabrol, 2016), and expression of schizotypy symptoms exist. However, previous research has not been directed toward further understanding the effects of an individual’s experience when using cannabis. This is the first study to investigate the relationships between schizotypy, cannabis experience, and social functioning. The overarching goal was that findings from this study would create a deeper understanding of how cannabis experiences affect individuals—specifically their ability to function in social capacities and how they perceive and interact with the world. Study one established that individuals who report paranoid/dysphoric or unpleasant after effects of cannabis also experience greater social functioning impairment. While both adverse cannabis experiences and schizotypy contribute to social functioning problems, higher levels of schizotypy have a larger, direct impact on a person’s ability to function in their social environment. Study two did not yield significant results. However, it showed a trend consistent with what is established in the current literature—that individuals with schizophrenia who use cannabis report more severe symptoms of psychosis compared to non-users.