Decriminalization of Marijuana and the Impact on Psychiatric Disorders

In the context of this study proposal, the researcher focuses on the decimalization of marijuana and the implications on the prevalence of psychiatric disorders across the population. There has been a shift in recent years surrounding legal and societal perspective on the decriminalization of marijuana. The non-medical use of marijuana is decriminalized across sixteen states in the U.S., including the United States Virgin Islands, and legalized almost 15 states. The increasing trend in decriminalization and legalization of marijuana across the U.S. states coincides with the intensified acceptance, declined in the perception of risk, and a surge in the usage of the drug among adolescents and adults (Leung, Chiu, Stjepanović, & Hall, 2018). Decriminalization policy on marijuana is the state response to the drug that reduces or eliminate criminal punishments for the possession of a small amount for personal use.

The drug use remains prohibited, but the criminal penalties eliminated or replaced with other civil sanctions (Smyth, Cannon, Molodynski, Curran, Eastwood, & Winstock, 2020). Grounded on the experience with commercial tobacco and the different countries and states in the world where marijuana is legalized for recreational use, including in Washington, there is substantial evidence that marijuana use prevalence may continue in the future (Leung, Chiu, Stjepanović, & Hall, 2018). However, researchers argue that the increased use of marijuana would pose disproportionate burden on psychiatric disorders in the United States. Psychiatric disorders denote a combination of mental illnesses, including mood and anxiety disorders, schizophrenia, and cannabis use disorders (CUD). Researchers have described marijuana use as among the numerous environmental influences linked to people’s susceptibility towards the development of psychotic disorders. Approximately one out of four marijuana user population showing a concurrent cannabis use disorders (CUDs)diagnosis (Guttmannova et al. 2017), prompting the need to study the impact of decriminalization of marijuana on psychiatric disorders across the United States.


Literature Review

Beginning in the late 1960s, decriminalization of cannabis became a movement, with the proponents advocating for reforms on federal laws that regulate marijuana use across different states. As a result, eleven states took measures to decriminalize marijuana use, reducing criminal punishment on possession of a small quantity of the drug. Currently, the non-medical use of marijuana is decriminalized across sixteen states in the U.S and while others have the drug legalized for medicinal purpose (Yu, Chen, Chen, & Yan 2020).  

However, researchers have linked decriminalization of marijuana to high prevalence use and increased case of psychiatric disorders. Decriminalization of marijuana causes problematic use, which in turn is connected to the prevalence of psychiatric disorders, particularly among the adolescents and young people who are the majority of the population (Yu, Chen, Chen, & Yan 2020). When one lacks protective self-regulatory aptitudes to manage emotional dysfunction, marijuana use may be adopted as a substitute to cope with the individual’s mental disorder. The initial reprieve from an affective state positively reinforces the behavior, ultimately translating into an allostatic form that produces a neurobiological affect Smyth, Cannon, Molodynski, Curran, Eastwood, & Winstock, 2020).

Charilaou, Agnihotri, Garcia, Badheka, Frenia, & Yegneswaran, (2017), in their study, noted that the problematic cannabis/marijuana use such as cannabis use disorders (CUD) is more prevalent in persons with psychiatric disorders such as mood and anxiety disorders, schizophrenia, post-traumatic stress disorders, schizophrenia, and personality disorders than the general public. The researchers further indicated that psychiatric symptoms predict both problematical cannabis use alongside the belief that marijuana is harmless because of decriminalization (Charilaou et al. 2017). Besides, as marijuana use becomes more clinically severe, studies indicate a more robust relationship between a diagnosis of cannabis use disorder and concomitant psychiatric disorders (Guttmannova et al. 2017). Guttmannova et al. described marijuana use as among the several environmental influences linked to the increased in vulnerabilities toward the development of psychotic diseases, with about 25% of the psychotic patients’ population presenting with a concurrent CUD diagnosis (Guttmannova et al. 2017).  

The delta-9-tetrahydrocannabinol (THC) in marijuana, for instance, is linked to the prevalence risks of psychosis in a dose-dependent manner. Research shows that regular and heavy marijuana users have about two and four-time chances of developing psychosis correspondingly compared to the general public (Charilaou et al. 2017). The surge in the risk for earlier symptoms of psychotic has been observed in relation to marijuana use in the general public. Study of about 50,000 male participants in the research conducted by Baggio et al., indicated that individuals who smoke marijuana as early as the age 18 years are were twice more likely to develop schizophrenia disorders. At the same time, chronic users were at six times at risk of being diagnosed with schizophrenia that the non-users (Baggio et al. 2014). The injection of intravenous THC to healthy people has also been shown to prompt psychotic symptoms both in “Positive and Negative Symptom Scale (PANSS)” and self-reported cases. The use of marijuana is also linked to more extended hospitalization period and overall poor health quality-of-life outcomes (Kim et al. 2015), including an earlier commencement of psychosis.

Prevalence use of marijuana as a result of decriminalization is also linked to the high prevalence of “major depressive disorder (MDD)” and “bipolar disorder (B.D.).” Much of major depressive disorders, most of the research evidence of the causes is linked to the adverse consequence of marijuana use. Schoeler, Theobald, Pingault, Farrington, Coid, & Bhattacharyya (2018), in their research finding from a 40-year follow-up surveying over 400 participants across different time points, concluded that marijuana use was linked to a surge in the risk of being diagnosed with MDD, and earlier introduction to marijuana was associated with early symptoms of MDD or MDD presentation (Schoeler et al. 2018). Other researchers have also demonstrated a similar pattern, an indication of a positive relationship between marijuana use and depression, which is further strengthened by chronic use (Baggio et al. 2014). Research also links the prevalence of marijuana use to high risk of early onset of bipolar disorder (B.D.), a mood disorder related to CUD. Cougle, Hakes, Macatee, Chavarria, & Zvolensky, in their survey using sample population of 40,000 individuals drawn countrywide, concluded that marijuana use has a high association with the risks of one developing bipolar disorders (B.D.) and the worsening of B.D. Symptomology, which includes, among others, the of suicide Cougle, Hakes, Macatee, Chavarria, & Zvolensky (2015).

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The study also links prevalence use of marijuana to anxiety disorders, despite the prevalent perception of cannabis improving the anxiety outcomes. Charilaou et al. (2017), in their research, reported significant evidence concerning a positive correlation between a daily marijuana use and social anxiety disorder (SAD) and agoraphobia, in a nationally representative survey. Other researchers have studied the impacts of marijuana use in adolescent and early childhood stages and suggested a high risk of developing an anxiety disorder, strengthened by an initial introduction to cannabis use (Copeland, Rooke & Swift, 2013).

Purpose of the Study Section

The purpose of the present research is to explore the correlation between the decriminalization of marijuana use and the prevalence of psychiatric disorders among the user population. Further understanding of this puzzle will entail the adoption of the self-medication, and the addiction vulnerability hypothesis to guide in the examination of whether decriminalization has potential therapeutic effects or its impact is more harmful in that it escalates psychiatric disorders. It is expected that decriminalization policies lead to a high prevalence of marijuana use across the population, which in turn translates into high incidences of psychiatric disorders among the users. It is also expected that mental illness acts as a vulnerability factor, priming an individual to self-medication with substances such as marijuana.


Baggio, S., N’Goran, A. A., Deline, S., Studer, J., Dupuis, M., Henchoz, Y., … & Gmel, G. (2014). Patterns of cannabis use and prospective associations with health issues among young males. Addiction, 109(6), 937-945.

Charilaou, P., Agnihotri, K., Garcia, P., Badheka, A., Frenia, D., & Yegneswaran, B. (2017). Trends of cannabis use disorder in the inpatient: 2002 to 2011. The American journal of medicine, 130(6), 678-687.

Copeland, J., Rooke, S., & Swift, W. (2013). Changes in cannabis use among young people: impact on mental health. Current opinion in psychiatry, 26(4), 325-329.

Cougle, J. R., Hakes, J. K., Macatee, R. J., Chavarria, J., & Zvolensky, M. J. (2015). Quality of life and risk of psychiatric disorders among regular users of alcohol, nicotine, and cannabis: An analysis of the National Epidemiological Survey on Alcohol and Related Conditions (NESARC). Journal of psychiatric research, 66, 135-141.

Guttmannova, K., Kosterman, R., White, H. R., Bailey, J. A., Lee, J. O., Epstein, M., … & Hawkins, J. D. (2017). The association between regular marijuana use and adult mental health outcomes. Drug and alcohol dependence, 179, 109-116.

Kim, S. W., Dodd, S., Berk, L., Kulkarni, J., De Castella, A., Fitzgerald, P. B., … & Berk, M. (2015). Impact of cannabis use on long-term remission in bipolar I and schizoaffective disorder. Psychiatry Investigation, 12(3), 349.

Leung, J., Chiu, C. Y. V., Stjepanović, D., & Hall, W. (2018). Has the legalization of medical and recreational cannabis use in the USA affected the prevalence of cannabis use and cannabis use disorders?. Current Addiction Reports, 5(4), 403-417.

Schoeler, T., Theobald, D., Pingault, J. B., Farrington, D., Coid, J., & Bhattacharyya, S. (2018). Developmental sensitivity to cannabis use patterns and risk for major depressive disorder in mid-life: findings from 40 years of follow-up. Psychological medicine, 48(13), 2169-2176.

Smyth, B. P., Cannon, M., Molodynski, A., Curran, H. V., Eastwood, N., & Winstock, A. R. (2020). Would decriminalizing personal use of cannabis lead to higher rates of mental illness?. BMJ. 368.

Yu, B., Chen, X., Chen, X., & Yan, H. (2020). Marijuana legalization and historical trends in marijuana use among U.S. residents aged 12–25: results from the 1979–2016 National Survey on drug use and health. BMC public health, 20(1), 156.