A study of adults seeking treatment for anxiety and related disorders in Canada found that individuals who reported using cannabis more frequently had poorer outcomes of cognitive-behavior therapy compared persons who used cannabis less often or not at all. In spite of this, cognitive-behavior therapy was quite effective at treating anxiety symptoms, even in the group of frequent cannabis users. The study was published in the Journal of Psychiatric Research.
Cognitive behavioral therapy (or CBT) is currently considered to be one of the most effective methods of treating anxiety and a number of related disorders. These include trauma- and stress-related disorders, obsessive-compulsive disorder, and others. Cognitive-behavioral therapy works by teaching patients cognitive and behavioral skills to manage anxiety. These skills are practiced between therapy sessions.
Persons seeking treatment for anxiety often endorse the use of cannabis. Some of them may be using cannabis to help manage anxiety symptoms. However, cannabis use and anxiety may be maintaining each other. Individuals may use cannabis to manage anxiety symptoms in the short term, but this can lead to later cannabis craving that is associated with anxiety.
In their new study, Melise J. Ouellette and her colleagues sought to explore whether there is an association between how often patients undergoing cognitive-behavioral therapy for anxiety and related disorders use cannabis and how effective this therapy is in reducing symptoms of the disorder. They were also interested to know if problems related with cannabis use are associated with the therapy outcome.
Participants were 253 adults seeking treatment for anxiety and related disorders with clinically significant levels of symptoms of the disorders he/she was seeking treatment for. Participants were asked to report on how often they used cannabis. Based on this, they were categorized into three groups – non-users (135 participants), infrequent users (45 participants) and frequent users (73 participants).
Apart from this, they completed assessments of the severity of daily life disruptions attributable to their illness, social anxiety, panic disorder symptoms, obsessive-compulsive disorder symptoms, and PTSD symptoms.
Results showed that anxiety symptom severity decreased in all groups during therapy. However, anxiety (or related) disorder symptoms improved less over time in frequent cannabis users than in the group of non-users.
There was no difference in the rate of improvement of symptoms during therapy between infrequent users of cannabis and non-users, but also between frequent and infrequent users. In other words, the rate of improvement of symptoms of infrequent users was between the rates of frequent users and non-users, but the difference in these rates was too small to be detectable using statistical analysis techniques researchers applied.
When only cannabis users were considered, the severity of cannabis-related problems was not associated with how quickly anxiety symptom severity changed during therapy.
“Cannabis use frequency was associated with poorer cognitive-behavioral therapy outcomes for anxiety and related disorders, however these individuals still made notable treatment gains,” the researchers wrote. “Cannabis-related problems were not a significant predictor of cognitive-behavioral therapy outcomes”
They added that “current results suggest that frequent cannabis use should not warrant unilateral exclusion from cognitive-behavioral therapy for anxiety and related disorders as patients generally benefit from cognitive-behavioral therapy despite their cannabis use. In fact, successful cognitive-behavioral therapy may have helpful downstream effects on cannabis use for those who use as a form of avoidance.”
The study is one of the first investigations into the relationship between cannabis use and effects of psychotherapy. However, it also has limitations that need to be taken into account. Notably, the study design does not allow any cause-and-effect conclusions about the relationships of studied factors. Additionally, cannabis use was assessed using self-report measures and the division into categories by how often a person uses cannabis was not based on any standardized method.
The study, “Does cannabis use impact cognitive behavioural therapy outcomes for anxiety and related disorders? A preliminary examination”, was authored by Melise J. Ouellette, Karen Rowa, Duncan H. Cameron, Ashleigh Elcock, Noam Soreni, Elizabeth J. Pawluk, and Randi E. McCabe.
