Cannabidiol for the Treatment of Anxiety Disorders: An 8-Week Pilot Study

This proposed study aims to evaluate the efficacy of daily Cannabidiol (CBD) Oil Capsules in treating symptoms of DSM-5 anxiety disorders, using a two-arm, 8-week randomized, placebo-controlled trial in adults aged 21-65 years. The study will also evaluate the relationship between inflammation, anxiety and CBD using biological markers as well as examine the neuro-cognitive effects of CBD treatment.

The study will be a randomized, double-blind, placebo-controlled parallel design comparing the efficacy and safety of flexibly dosed CBD Oil capsules versus placebo for the treatment of adults, aged 21 to 65 years with a primary Diagnostic and Statistical Manual 5 (DSM-5) anxiety disorder: Generalized Anxiety Disorder (GAD), Social Anxiety Disorder (SAD), Panic Disorder (PD), or agoraphobia. A total 50 participants (n=25/cell) who meet the inclusion criteria will be randomized to receive 1 of 2 treatments in a 1:1 ratio: CBD Oil Capsules or matching placebo, with the possibility of dose titration during this 8-week period. The outcomes of this research will make a significant contribution to enhance our current understanding of the effects of cannabis in anxiety disorders.

To be involved in this study, the study doctor will first check that the participant is qualified. This is called screening, and will involve a clinical assessment, physical exam and urine tests. This visit may take up to 3 hours to complete.

If the participant successfully completes screening the participant will start treatment in one of the two assigned treatment groups. Treatment is 8 weeks. Participants will come to the study clinic 6 times during the treatment phase of the study. Each visit will last 1 to 2 hours. Each visit will involve reporting any side effects that the participant may have experienced, completing questionnaires about mood and anxiety symptoms, sleep, overall functioning and alcohol and drug use. Participants will also be assessed by the study doctor. The first and last visits will also involve blood work and completing a number of tasks on the computer, which measure focus, attention and memory.

Each participant will be involved in the study for a maximum of 10 weeks. This includes the screening visit and follow-up visit.

Eligibility Criteria:
Inclusion Criteria:

1. Male or female outpatients 21-65 years of age with a primary psychiatric diagnosis of either GAD, SAD, PD or agoraphobia as defined by DSM-5 criteria and a HAM-A score of ≥ 22.
2. Physical exam and laboratory findings without clinically significant abnormalities.
3. Participants must agree to abstain from recreational cannabis use for the duration of the study.
4. Concomitant psychotropic medication use will be allowed provided that the dose has been stable for 8 weeks prior to randomization. (including antidepressants, anti-psychotics, anti-convulsants, benzodiazepines, stimulants, mood stabilizers)
5. The ability to comprehend and satisfactorily comply with protocol requirements.
6. Written informed consent given prior to entering the baseline period of the study.

Exclusion Criteria:

1. Current recreational or medicinal use of cannabis within 4 weeks of study initiation.
2. Participants with a lifetime history of cannabis use disorder or other substance use disorders (except tobacco use disorder)will be excluded.
3. Participants with a lifetime history of daily cannabis use will be excluded.
4. Dose changes of concomitant medication will not be permitted during the study period.
5. Pregnant women, lactating women, and women of childbearing potential who are not using medically accepted forms of contraception (e.g., IUD, oral contraceptives, barrier devices, condoms and foam, or implanted progesterone rods stabilized for at least 3 months), or women who are planning on becoming pregnant.
6. Diagnosis of any of the following mental disorders as defined by the DSM-5: a lifetime history of schizophrenia or any other psychosis, mental retardation, organic medical disorders, bipolar disorder. Entry of patients with obsessive compulsive disorder or posttraumatic stress disorder will be permitted if the anxiety disorder is judged to be the predominant disorder, in order to increase accrual of a clinically relevant sample.
7. Major depression will be allowed if not severe (Montgomery Asberg Depression Rating Scale-MADRS ≥ 25). Patients with significant suicidal ideation (MADRS item 10 score \> 3) or who have enacted suicidal behaviours within 6 months prior to intake will be excluded from study participation and referred for appropriate clinical intervention.
8. Participants with a family history of psychosis will be excluded.
9. Participants who have a history of adverse reactions to cannabis will be excluded.