‘There’s a real risk there’: Cannabis use exacerbates depression

CHICAGO — Cannabis has been approved by state legislators across the United States for more than 50 medical indications, according to a speaker at the ACP Internal Medicine Meeting.

Kari L. Franson, PharmD, PhD, BCPP, a professor of clinical pharmacy at the University of Southern California, said these indications include Alzheimer’s disease (n = 15 states), epilepsy/seizures (n = 31 states), nausea (n = 20 states), amyotrophic lateral sclerosis (n = 22 states), pain (n = 30 states), autism (n = 14 states), Parkinson’s disease (n = 15 states), cachexia (n = 24 states), hepatitis C (n = 11 states), peripheral neuropathy (n = 11 states), cancer (n = 30 states), HIV/AIDS (n = 31 states), PTSD (n = 30 states), Crohn’s disease (n = 20 states), multiple sclerosis (n = 22 states), Tourette’s syndrome (n = 7 states) and glaucoma (n = 27 states).

“I’ll tell you right now, [cannabis] doesn’t work for glaucoma,” Franson said during the presentation. “Isn’t it funny that 27 states have it as something that it is legal for? So, it’s not evidence based. It’s based on compassion.”

For the most part, Franson said that she only considers recommending medical cannabis when patients ask about it. Among all the indications, only pediatric seizures, MS and pain have “reasonable data” to suggest cannabis is beneficial, she added.

“The evidence for using THC-type cannabis for pain is quite good,” Franson said.

The short-term effects associated with THC-type cannabis include dizziness, disorientation, euphoria, dry mouth, somnolence, nausea/vomiting, fatigue, depression and anxiety. Less is known about the long-term effects, Franson said. But evidence suggests that it can cause cannabinoid hyperemesis syndrome, stroke, acute myocardial infarction, impaired cognitive functioning and psychiatric effects such as insomnia, anxiety, cannabis use disorder, psychosis and depression.

Although recent research has shown that cannabis can reduce depression in the short term, the symptoms appear to worsen over time. This was demonstrated in a naturalist study conducted in Canada. Most patients (89%) who reported feeling stressed, anxious or depressed had a 50% reduction in depression after 20 minutes of cannabis use, and 94% had a 58% reduction in anxiety, according to Franson. However, baseline symptoms of depression exacerbated gradually.

“This is the thing that I really would love to see imprinted in your brains when you all walk out of here,” Franson told attendees. “I see a lot of patients who use cannabis chronically and really struggle with depression. I can’t stress to you enough how difficult it is to talk to a patient about their depression symptoms when they’re utilizing cannabis and they are convinced how much it makes them feel better.”

The risk for depression — and other poor outcomes — is particularly evident in adolescents, Franson said.

A previous meta-analysis of 11 longitudinal and prospective studies showed that adolescents who used cannabis were more likely than nonusers to attempt suicide (OR = 3.46; 95% CI, 1.53-7.84), experience suicidal ideation (OR = 1.5; 95% CI, 1.11-2.03), and develop depression (OR = 1.37; 95% CI, 1.16-1.62) or anxiety (OR = 1.18; 95% CI, 0.84-1.67).

“There’s a real risk there,” Franson said.

References:

Cuttler C, et al. J Affect Disord. 2018;doi:10.1016/j.jad.2018.04.054.

Franson K. Cannabis: Harmful or healing? Presented at: ACP Internal Medicine Meeting; April 28-30 2022; Chicago.

Gobbi G, et al. JAMA Psychiatry. 2019;doi:10.1001/jamapsychiatry.2018.4500.