Cannabis Legalization Impacts Use of Psychiatric Medications

Cannabis laws impact prescriptions for psych meds differently.

Reviewed by Gary Drevitch

Key points

• Cannabis alters brain function, thereby altering the mind.
• The legalization of medical and recreational cannabis impacts prescriptions for psychiatric medications.
• Anxiolytic prescriptions are altered differently than antidepressant and antipsychotic prescriptions.

Some legitimate questions cannot be researched using the “gold standard” of double-blind methodology needed to establish direct cause and effect. Instead, we need to rely on large computer databases and statistical analysis to provide perspective on the degree to which two events are associated with each other. A new study of over 10 million anonymized commercially insured patients looked at whether the use of anxiolytic (i.e., benzodiazepines), antidepressant, and antipsychotic medications is changed by state laws permitting the medical use, recreational use, or no legal use of cannabis.[i] The study’s authors proposed this would be a very interesting thing to know, "given perceptions about the potential effect of cannabis on individuals with mental health disorders.”

In states, legalizing medical cannabis is associated with a 12.4% reduction in the fill rate of benzodiazepine prescriptions, and those states with legal recreational cannabis, legalization is associated with a 15.2% fill rate reduction. This reduction of benzodiazepine use is not surprising given the well-established fact that cannabis products generally have an anxiolytic effect for most people. This study suggests that people in states with the availability of legal cannabis offer an “over the counter” alternative to prescription benzodiazepines, which requires a physician’s ongoing approval. The ease of obtaining cannabis, along with its bonus sensations (from subtle to profound) could appeal to people who see no value in consulting an expensive physician or are embarrassed to do so. Furthermore, good medical practice encumbers benzodiazepine use with cautions regarding overuse and addiction while many cannabis dispensaries may issue no such warnings about their products.

On the other hand, legalization of medical and recreational cannabis is associated with the opposite impact on antidepressant and antipsychotic prescriptions, though the major impact seems related to the legalization of medical cannabis and less to that of recreational cannabis. The opening of local legal medical cannabis dispensaries is associated with an 8.8% increase in antidepressant prescription fills. Prescriptions for antipsychotic medications increased by 2.5% after medical cannabis laws passed and by 2.5% when medical cannabis dispensaries opened.

“Thus,” researchers concluded, “access to cannabis may represent a meaningful shift in mental health treatment for this population.” Any decrease in benzodiazepine use would potentially lead to fewer medically important negative consequences due to addiction, intended and unintended overdoses, and falls in the elderly. On the other hand, these positives might be counterbalanced by increased depression (see Cannabis, Depression, and Bipolar Disorder) and psychotic disorders known to be caused by use of high concentration THC cannabis products (see Cannabis Connection to Psychosis). In addition, there is always the risk of increasing cannabis addiction when more people use it (see Prevalence of Cannabis Use Disorder Among Cannabis Users).

Bottom line: People are complex, as are mental health disorders and both prescription and non-prescription medications. Highly complex. The introduction of cannabis to the mix, whether it is termed medical (generally sold by non-medical entrepreneurs) or recreational, muddies the water for mental health workers. Cannabis is not candy, although it provides some of the same pleasures. It contains a large group of compounds that alter brain function, thereby changing mental experience, which is the point of people using it. As a result, mental health workers need to be told if you are using cannabis. And mental health workers need to understand the full implications cannabis use might have on patient treatment.

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