Cannabis and Psychosis Through the Lens of DSM-5

Abstract

Evidence for an association between cannabis and psychosis has been documented in literature in many forms including experimental studies, epidemiological data, and case series. The association has implications for psychotic outcomes ranging from mild to severe and occurring over minutes to years. Due to the huge variety of exposures and outcome measures reported, creating a coherent account of all the available information is difficult. A useful way to conceptualize these wide-ranging results is to consider the association between cannabis and psychosis as it occurs within the context of widely used DSM-5 diagnoses. In the present review we examine cannabis/psychosis associations as they pertain to Cannabis Intoxication, Cannabis-Induced Psychotic Disorder, and Schizophrenia. This allows for an understanding of the cannabis and psychosis association along something approaching a continuum. Cannabis intoxication becomes Cannabis-Induced Psychotic Disorder once certain severity and duration criteria are met and Cannabis-Induced Psychotic Disorder is heavily associated with future schizophrenia diagnoses.

The Association Between Cannabis Use and Schizophrenia: Causative or Curative? A Systematic Review

“…There are clear psychiatric comorbidity and cognitive decline in cannabis use disorder [13]. A person ever exposed to cannabis in his/her lifetime is at a higher risk of schizophrenia development [10]. There is a high frequency of psychotic disorders with cannabis users, and cannabis also alters the age of onset and course and presentation of the disease [13].…”

“…Case-control studies show that earlier and higher doses of cannabis use lead to the more rapid development of psychotic symptoms [10,15]. Frequent use of cannabis, especially the start of use at a younger age, doubles the risk of schizophrenia development in the future [16].…”

“…Brain-derived neurotrophic factor (BDNF), cannabinoid receptor 1 (CNR1), catechol-o-methyl transferase (COMT), protein kinase B also known as AKT1, and dopamine receptor D2 (DRD2) are some of the genes that are at risk of developing schizophrenia after early cannabis exposure; however, the transition rate is meager [18]. Cannabis changes the natural course of psychotic symptoms in the genotype Met/Met [10]. From this data, we can say that harm minimizing approach aiming at dose reduction or later onset of use can be relevant in the prevention and treatment of psychosis [19].…”

“…Schizophrenia has a group of "positive" and "negative" symptoms. Positive symptoms are delusions, hallucinations, disorganized speech/ behavior/ thinking, and negative symptoms are diminished expressions, avolition, alogia, anhedonia, and asociality [10]. The presence of delusions or hallucinations is also known as a psychotic disorder [9].…”

“…The presence of delusions or hallucinations is also known as a psychotic disorder [9]. Psychosis describes symptoms, whereas schizophrenia is a chronic illness that includes severe psychotic symptoms [10]. According to DSM-5, schizophrenia and brief psychotic disorder are a part of the schizophrenia spectrum, a group of disorders [9].…”