A six-month study conducted by Johns Hopkins University School of Medicine has found that THC-dominant medicinal cannabis use is associated with significant reductions in anxiety and depression symptoms, with patients experiencing sustained improvements in their mental health.
The research, published in the Journal of Affective Disorders, followed 33 participants with clinically significant anxiety or depression who were new to cannabis use. All participants used state-authorised medical cannabis products, including botanical and edible preparations, as needed over the six-month study period.
“Initiation of THC-dominant medicinal cannabis was associated with acute reductions in anxiety and depression, and sustained reductions in overall symptom severity over a 6-month period,” researchers reported. The study also found improvements in patients’ quality of life and overall health satisfaction, with no associated development of physical or psychological problems.
The study employed ecological momentary assessment (EMA) – a research method used to understand people’s thoughts and behaviour in their daily lives by collecting data in a normal environment – to track both acute and chronic effects of cannabis use. Participants also completed Hospital Anxiety and Depression Scale (HADS) assessments before starting treatment, and at one, three, and six months after beginning cannabis use.
Results showed that mean anxiety and depression scores dropped below clinically significant levels within three months of cannabis initiation. The EMA data revealed that most participants selected THC-dominant cannabis products, experiencing acute reductions in anxiety and depression symptoms alongside increased ratings of feeling “high”.
The research identified dose-dependent effects, with 10-15 mg of oral THC and at least three puffs of vaporised cannabis yielding the most robust reductions in anxiety and depression symptoms.
The study’s authors concluded that the positive response “reflected by reductions in anxiety and/or depression by most participants, support the need for continued investigation of medicinal cannabis or related cannabinoid therapeutics as pharmacological treatments for anxiety and depression symptom relief, ideally with randomised, placebo-controlled trials”.
The research adds to growing evidence that cannabis legalisation may be associated with reduced use of traditional psychiatric medications, including benzodiazepines and anti-depressants.
