Publication
Article
Psychiatric Times
Is the Case Settled? Cannabis and Criminal Responsibility
Author(s):
Key Takeaways
- Cannabis-induced psychosis complicates criminal responsibility, with settled insanity as a potential defense if symptoms persist beyond intoxication.
- Legal standards for insanity and diminished capacity vary by jurisdiction, affecting the applicability of voluntary intoxication as a defense.
Understanding the complex relationship between substance use and mental health is critical to providing thorough and well-informed evaluations. Let's take a look at the relationship between cannabis and criminal responsibility.
roxxyphotos/AdobeStock
Case Study
“John,” a 25-year-old man with no prior criminal history, was arrested after breaking into a convenience store in the middle of the night and assaulting the clerk with a knife. Witnesses reported erratic and violent behavior, including shouting about being chased by invisible enemies. Upon arrest, John was incoherent, disoriented, responding to internal stimuli, and exhibiting signs of paranoia. He was charged with assault with a deadly weapon. While incarcerated for several months, John continued to exhibit signs of psychosis and was found incompetent to stand trial. His family revealed that John had heavily used high-potency cannabis for several years and had experienced increasing paranoia and auditory hallucinations over the past year. After more than 6 months of involuntary treatment with antipsychotic medication, John was ultimately deemed competent to stand trial.
At trial, John’s defense team contended that he was not guilty by reason of insanity, asserting that his prolonged cannabis use had led to a state of settled insanity, which he was experiencing at the time of the crime. However, the prosecution countered by pointing to the fact that John’s psychosis resulted from voluntary intoxication, a condition often excluded from insanity defenses.
Criminal Responsibility
Findings from studies have shown an increased use of cannabis in the US resulting from its legalization for recreational purposes.1 However, findings from studies on the effects of recreational cannabis legalization on mental health issues have shown mixed results.2 Recent cases have highlighted the relationship between cannabis and criminal responsibility, particularly with regard to intoxication and its impact on a defendant’s mental state.3
Criminal responsibility refers to the extent to which a person can be held legally accountable for committing a crime. In such cases, defendants may raise various mental defenses to argue that their mental state at the time of the offense diminishes or negates their responsibility for the act. The insanity defense is one of the most well-known mental defenses. The exact standard for determining legal insanity has differed across time and jurisdictions, but it typically means that due to a mental illness or defect, an individual cannot recognize an act is wrong, fails to understand the nature or quality of the act, or is unable to control their behavior.4 Typically, a substance-induced disorder resulting from the voluntary consumption of an intoxicating substance, such as cannabis, does not constitute a mental disease or defect for the purposes of the insanity defense.4 However, in certain jurisdictions, the defense of settled insanity may offer an alternative route for defendants whose cannabis use leads to prolonged psychotic symptoms. If it can be shown that substance use triggered or worsened psychotic symptoms that continued beyond the acute effects of intoxication, the defendant may be eligible to use the defense of settled insanity.5
Settled Insanity
The standard for settled insanity varies by jurisdiction and is not always clearly defined.3 Although the specific criteria may differ across regions, the challenge of separating the effects of mental illness from substance use remains consistent. Establishing a clear timeline for the onset of substance use and symptoms of mental illness can be difficult and at times even impossible. Evidence indicating that the defendant showed signs of mental illness close to the time of the offense but prior to substance use or that the symptoms present during the offense persisted beyond the effects of intoxication may support the determination of settled insanity.6 For instance, the persistence of psychotic symptoms far beyond what would be expected from cannabis intoxication alone, requiring significant clinical intervention, could support an opinion of symptoms that are more settled and not merely a result of acute intoxication. Once it is established that a lasting impairment may be at play, the forensic evaluator must assess whether the symptoms meet the statutory criteria for the insanity defense. Experts assessing defendants for a potential insanity defense in cases involving substance use may consider examining the factors outlined in the Table.6,7
Table. Data to Consider in the Evaluation of Settled Insanity6,7
Diminished Capacity
All crimes, except strict liability offenses (where the prosecution is not required to prove that the defendant had intent or knowledge of committing the crime), require both an action (actus reus) and criminal intent (mens rea).8 If mens rea is absent, an individual cannot be found guilty of a crime that necessitates intent. Courts distinguish between general intent and specific intent crimes, with voluntary intoxication being relevant to the latter.9 Specific intent crimes require not only the intent to perform the criminal act but also the intention to achieve a specific result. If cannabis intoxication impaired the defendant’s ability to form this specific intent, it could serve as a partial defense.9 For example, a defendant charged with a specific intent crime, such as first-degree murder, may argue that due to cannabis-induced psychosis, they were unable to premeditate or intentionally carry out the killing. This in turn could result in a reduction of charges. A general intent crime requires that the defendant intended to commit the criminal act but not necessarily to achieve a particular result.9 For these crimes, it is enough that the individual acted with a wrongful purpose, even if they did not intend to cause a specific outcome. Voluntary intoxication is never accepted as a defense, not even a partial one, for general intent crimes.9
Mitigation
Voluntary intoxication may be considered during the sentencing phase of a criminal proceeding. Some jurisdictions allow judges to consider the defendant’s intoxicated state when determining the severity of the sentence. In Texas, for example, voluntary intoxication may be cited as a mitigating factor in sentencing.10 A mitigating factor is a circumstance or piece of evidence that can reduce the severity of a defendant’s sentence or level of criminal responsibility, even if they are found guilty of a crime.9 Mitigating factors do not excuse the crime but help explain why it may have occurred, suggesting that a lesser punishment is more appropriate.
Concluding Thoughts
The laws regarding voluntary intoxication and mental health defenses differ significantly among jurisdictions, making it important for forensic psychiatrists to be well-versed in the legal standards of the area where a case is being tried.7 Whether or not voluntary intoxication can be used to argue diminished capacity or as a mitigating factor at sentencing varies widely. The recognition of settled insanity where long-term substance use results in lasting mental impairment even after intoxication has ended adds another layer of complexity.
Understanding the complex relationship between substance use and mental health is critical to providing thorough and well-informed evaluations. Staying up to date on both the evolving science of substance-induced psychiatric conditions and jurisdiction-specific legal standards ensures that forensic assessments remain aligned with contemporary practices and legal standards. As cannabis and other substances become more prevalent in legal contexts, expertise in this area will only grow in importance.
Dr Hanif is a forensic psychiatrist and assistant professor in the Menninger Department of Psychiatry & Behavioral Sciences at the Baylor College of Medicine as well as a psychiatrist at Ben Taub General Hospital within the Harris Health System, both in Houston, Texas.
References
1. Farrelly KN, Wardell JD, Marsden E, et al. The impact of recreational cannabis legalization on cannabis use and associated outcomes: a systematic review. Subst Abuse. 2023;17:11782218231172054.
2. Elser H, Humphreys K, Kiang MV, et al. State cannabis legalization and psychosis-related health care utilization. JAMA Netw Open. 2023;6(1):e2252689.
3. Appelbaum PS. Settled insanity: substance use meets the insanity defense. Psychiatr Serv. 2022;73(1):105-107.
4. Felthous AR. Chapter 29: criminal responsibility. In: Rosner R, Scott CL, eds. Principles and Practice of Forensic Psychiatry. 3rd ed. CRC Press; 2017:267-273.
5. Carter-Yamauchi CA. Drugs, Alcohol and the Insanity Defense: The Debate Over “Settled” Insanity. Legislative Reference Bureau. 1998. Accessed September 25, 2024. https://lrb.hawaii.gov/wp-content/uploads/1998_DrugsAlcoholAndTheInsanityDefense.pdf
6. Feix J, Wolber G. Intoxication and settled insanity: a finding of not guilty by reason of insanity. J Am Acad Psychiatry Law. 2007;35(2):172-182.
7. Glancy GD, Ash P, Bath EP, et al. AAPL practice guideline for the forensic assessment. J Am Acad Psychiatry Law. 2015;43(suppl 2):S3-S53.
8. Cross N. Criminal justice, actus reus and mens rea. In: Corteen K, Steele R, Cross N, McManus M, eds. Forensic Psychology, Crime and Policing. Policy Press; 2023:108-113.
9. Marlowe DB, Lambert JB, Thompson RG. Voluntary intoxication and criminal responsibility. Behav Sci Law. 1999;17(2):195-217.
10. Tex Pen Code 2, §8.04 (2024).
