Marijuana use is now a legal activity in many parts of the United States, but those managing patients with psychiatric disorders are in the difficult position of determining whether this use is helpful, harmful, or irrelevant to the underlying illness on the basis of limited and largely incomplete data, according to an overview of this issue presented at the virtual Psychopharmacology Update presented by Current Psychiatry and the American Academy of Clinical Psychiatrists.
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While there is clear evidence that cannabis use relative to the general population “is more prevalent among patients with psychiatric disorders,” it is less certain how often this use is risky, said Diana M. Martinez, MD, professor of psychiatry at Columbia University in New York.
Dr. Diana M. Martinez
Independent of euphoric effects, cannabis can be perceived by individuals with psychiatric diagnosis as self-medication for feelings of stress, social anxiety, and insomnia, among other symptoms. These are the same reasons why many individuals without psychiatric conditions use cannabis-containing products.
The perception that cannabis use is generally benign presumably explains the successful efforts at legalization, but there are risks for those with or without psychiatric illnesses, Dr. Martinez pointed out at the meeting, sponsored by Medscape Live. Not least, about 20% of regular users of cannabis develop cannabis use disorder (CUD), a condition defined in the DSM-5 as the continued use of cannabis despite adverse consequences, such as dependence.
Impact of severe CUD ‘incapacitating’
“Of those who meet criteria for CUD, 23% have severe CUD, which is an incapacitating form,” reported Dr. Martinez, citing work led by Deborah Hasin, PhD, professor of clinical epidemiology at Columbia University.
However, relative to otherwise healthy individuals, those with a psychiatric diagnosis might face greater benefits or greater risks from cannabis use, according to Dr. Martinez, who cited a 2017 report from the National Academies of Science, Engineering, and Medicine (NASEM).
This report evaluated the potential risks and benefits on the basis of published studies.
There is limited evidence that regular cannabis increases rather than modifies symptoms of mania and hypomania in patients with bipolar disorder, according to the report. The report also cited limited evidence that cannabis use increases severity of posttraumatic stress disorder (PTSD). There was limited evidence of adverse effects on symptoms of anxiety, although this appeared to depend on daily or nearly daily use.
The report found no data of acceptable quality to draw conclusions about the effect of cannabis use on symptoms of depression.
In patients with attention-deficit/hyperactivity disorder (ADHD), “a recent study showed that daily but not occasional use of cannabis increased impulsivity but not inattention, working memory, or verbal intelligence,” said Dr. Martinez, citing a study published this year.
Some evidence also suggests that patients with a psychiatric disorder might benefit from cannabis use, but, again, this evidence is limited. For one example, it includes a potential reduction in symptoms of obsessive-compulsive disorder, Dr. Martinez said.