Venlafaxine May Make It Harder to Kick the Marijuana Habit
By Will Boggs, MD
NEW YORK (Reuters Health) - For depressed patients hooked on pot, venlafaxine extended-release doesn't improve depression and may increase their cannabis use, a placebo-controlled trial shows.
"The findings are clearly contrary to expectations," said Dr. David Allsop from Australia's National Cannabis Prevention and Information Center at The University of New South Wales in Randwick, who was not involved in the study. Particularly surprising, he told Reuters Health in an email, was "that those on the drug were less likely to reduce their use."
Cannabis dependence doubles the likelihood of having a depressive disorder, and depression is common among cannabis-dependent patients seeking treatment, suggesting that identification and treatment of depression could help depressed cannabis-dependent patients.
Dr. Frances R. Levin from New York State Psychiatric Institute, New York, and colleagues tested this notion in a randomized, double-blind, placebo-controlled trial in 103 depressed, cannabis-dependent patients, half assigned to venlafaxine extended-released and half to placebo.
As reported online March 21 in Addiction, more than three times as many patients in the placebo group managed to go at least two weeks without cannabis, which was the primary outcome (36.5% vs 11.8%).
When patients with comparable baseline THC (tetrahydrocannabinol) levels were analyzed, those receiving placebo had 4.51-fold greater odds of achieving two weeks of continuous abstinence than those receiving venlafaxine.
The two groups did not differ in the proportions of patients who experienced 50% improvements in depression scores or who scored below 8 on the Hamilton Depression Inventory.
Among secondary outcomes, mean THC levels were higher in the venlafaxine group than in the placebo group throughout the study. In the placebo group, reductions in THC level were associated with improvements in depression, whereas THC levels remained high in the venlafaxine group even when depression scores were low.
Loss of libido was the only side effect that was more common in the venlafaxine group than in the placebo group, and medication compliance did not differ between the treatment groups.
"Clinicians managing depressed, cannabis-dependent patients who are not responding to outpatient counseling might consider more intensive psychosocial interventions or antidepressants," the researchers conclude, "although to date there are few data supporting the efficacy of antidepressants in cannabis-dependent individuals with depression."
"The low abstinence rates for both treatment arms suggest the need for further treatment development efforts for this population," the investigators add.
"Talking to people about their cannabis use is worthwhile," Dr. Allsop added. "It can interact with many areas of people's lives that might bring them into a treatment setting - oftentimes not directly related to or asking for help for cannabis use."
"Awareness needs to be raised to begin deconstructing the normalization of cannabis use," Dr. Allsop said. "It can and does cause harms - it has a withdrawal syndrome that can lead to relapse/continued use - and cannabis users often are not aware of these points. Psychoeducation, raising awareness, and cognitive behavioral therapy (CBT) can all make a difference, and of course where depression is severe, appropriate medications are called for irrespective of the cannabis use."
"As there are currently no accepted medications for cannabis use, the area is one of very active research activity," Dr. Allsop noted. His group has just finished a randomized trial of nabiximols (Sativex), a cannabinoid-based medication comprising THC and cannabidiol, for attenuation of cannabis withdrawal symptoms. He said the trial showed "considerable success" but was an inpatient study, so more work is needed.
Also, he added, Dr. Margaret Haney in the U.S. has tested nabilone, a synthetic THC analogue with some success as well, but here again the work is in its early stages.
Dr. Levin did not respond to a request for comment on this report.
SOURCE: https://bit.ly/11hoHZ7
Addiction 2013.
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