More support for cannabis in medical disease
Relative to the quality of evidence supporting benefit from cannabis in psychiatric disease, the data appear to be stronger for patients with medical illnesses, such as cancer. For example, Dr. Martinez cited evidence that tetrahydrocannabinol (THC), a major active ingredient in cannabis, improves sleep in the context of a medical illnesses. There is also evidence for anxiolytic effects in patients with a medical illness, although that is weaker.
In patients with or without a psychiatric disorder, marijuana does pose a risk of substance abuse disorder, and it shares the risks of intoxicants, such as inattention leading to increased risk of accidents, including motor vehicle accidents. This pertains to those with or without a psychiatric or medical condition, Dr. Martinez said.
While intermittent light use of cannabis appears to pose no risk or a very low risk of long-term adverse effects on cognition, at least in patients without psychiatric disorders, Dr. Martinez indicated that the risk-benefit ratio for any individual is use dependent. The risk of CUD, for example, increases with the frequency of exposure and the potency of the cannabis.
Empirical evidence for therapeutic role
In published studies, other researchers have expressed interest in a potential therapeutic role of cannabis for psychiatric disorders, but there appears to be a general consensus that the supportive data remain weak. One expert who has written on this topic, Jerome Sarris, PhD, professor of integrative mental health, NICM Health Research Institute, Western Sydney University, Westmead, Australia, said that empirical evidence does support a benefit in selected patients.
“Of course, high THC forms are strongly discouraged in people with schizophrenia or high risk of developing psychotic disorder, or in youths,” Dr. Sarris explained. “However, there is a potential role for use in people with sleep and pain issues, and many find it beneficial to also assist with affective disorder symptoms.”
In a systematic review he led that was published last year, the evidence to support cannabis for psychiatric disorders was characterized as “embryonic.” However, small studies and case reports appear to support benefit for such indications as ADHD if precautions are taken.
“I certainly would not discourage use of prescribed standardized medicinal cannabis therapeutics for all people with psychiatric disorders,” Dr. Sarris said. He suggested that attention should be made to the THC potency and terpene composition of the products that patients with psychiatric disorders are taking.