How is Substance Use Linked to Psychosis? A Study of the Course and Patterns of Substance Dependence in Psychosis

Abstract

Substance use in mentally ill patients is now a major problem that influences the course and outcome of psychosis. With prevalence ranging up to 60%, several theories were postulated to explain the link. It would be interesting to know if substances have different effects in persons with psychosis than in those without. This study aimed to explore patterns of symptomatology of dependence and comorbid psychiatric illness by comparing and contrasting it with a group suffering from pure substance dependence. Consecutively admitted patients who were matched for age, sex, and tobacco use were divided into 3 groups. These were substance dependence without any comorbid psychiatric disorder (SD; n = 32), schizophrenia with substance dependence (SC; n = 31), and bipolar disorder with substance dependence (BD; n = 31). Patients were administered the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and Mini International Neuropsychiatric Inventory (MINI) to evaluate the chronology of criterion of International Classification of Diseases (ICD)-10 dependence. Results showed that cannabis was the most common substance used by both the SC (100%) and BD (80%) groups. This was followed by alcohol as the most common substance used, with prevalence of 87% in SC and 77% in BD groups. There was a significant difference in the pattern of use of cannabis in patients with psychosis, who developed tolerance much faster (P = .018) and had longer durations of cannabis use (P = .001) than the SD group. The presence of "loss of control" over drug use criterion seems to be a specific marker predicting development of dependence and psychosis. Cannabis use is more strongly associated with development of psychosis than any other substance.

A comparative study of socio‐demographic and substance use correlates in early‐onset psychosis

“…6 Cannabis, alcohol and nicotine are the most commonly used substances globally, and there is often polysubstance use in patients with mental illness and particularly psychosis. 7 Cannabis use is also associated with various other non-psychotic mental illnesses in adolescents, including conduct disorders, attention deficit hyperactivity disorder (ADHD), depression and suicidal behaviour. 8 For example, in a review of 236 adolescent psychiatric patients in Israel, the most common diagnoses among cannabis users were ADHD and disruptive behaviour disorder.…”

“…11 Studies have also reported that adult patients with psychosis have a different pattern of substance use with earlier tolerance, loss of control and onset of dependence. 7 This has not been investigated in exclusive adolescent samples.…”

Legal substance use and the development of a DSM‐IV cannabis use disorder during adolescence: the TRAILS study

“…At the same time, early onset of cannabis use and at least weekly cannabis use during adolescence have been identified as risk factors for problems later in life. For instance, cannabis use in this age period may impair educational performance, may cause respiratory disease in the long term and increases the probability of developing psychotic symptoms [1][2][3][4][5][6]. Besides these adverse outcomes, it has been estimated that one in seven adolescents who have ever tried cannabis will experience dependency problems during their life-time [7].…”

La présence et la gravité des troubles de santé mentale sont-elles liées à la nature de la crise, à la dangerosité et aux services de crise offerts ?

“…Ceci s'explique fort probablement par le fait qu'elles sont plus isolées, moins souvent en couple et que peu d'entre elles ont des enfants. À l'inverse, ces personnes mentionnent des difficultés plus notables sur le plan de la consommation de drogues dures et douces, possiblement dans une optique d'automédication (Saddichha, Sur, Sinha et Khess, 2010). En effet, il est reconnu que l'observance à la médication constitue un enjeu majeur pour les personnes souffrant de troubles psychotiques (Joy, Adams et Rice, 2006).…”