Chronic headaches are a major cause of disability among adolescents. Cannabis products have supported the management of headaches in adults and may play a role in pediatric chronic pain. We propose a multisite, open-label, tolerability study conducted across three centers in Canada of Cannabidiol-enriched Cannabis Herbal Extract in adolescents (ages 14 to 17 years old) with chronic headaches. The study includes a one month baseline assessment, four months of escalating treatment doses and a weaning period. Our primary outcome is tolerability defined as the number and severity of reported adverse events.

Inclusion Criteria:

To be eligible to participate in this study, an individual must meet all of the following criteria:

1. Adolescents aged between 14-17 years of age at the time of screening.
2. Diagnosed with Chronic Migraine according to ICHD-3: headache (migraine-like or tension-type like) occurring on 15 or more days per month for more than 3 months which on at least 8 days per month have features of migraine headache. [121]
3. Failed at least two treatment options on the grounds of safety (tolerability) and/or efficacy, including but not limited to antidepressant (tricyclic antidepressant or selective norepinephrine reuptake inhibitor), magnesium, gabapentinoids topiramate and/or non-pharmacological therapies.
4. Females who have reached menarche should have a negative pregnancy test during screening.
5. Must be willing to engage with psychology and physiotherapy throughout the trial as appropriate.

Exclusion Criteria:

1. As per the investigator judgement, the participant is not an ideal candidate due to a personal issue or medical condition that is likely to impede in the successful completion of the study
2. Participants with a history of post-concussion headache or new daily persistent headache
3. Participants with a diagnosis of medication overuse headache
4. Participants with cardiac, renal or hepatic disease (assessed by the site investigator)
5. Participants with complex regional pain syndrome-II
6. Participants with abnormal ECG findings at baseline (as determined by the investigator)
7. Participants who are on the following medications: opioids, antipsychotics, antimanic, barbiturates, benzodiazepines, muscle relaxants, sedatives, or tramadol.
8. Participants with developmental delay or impairments including autism, cerebral palsy or intellectual disability.
9. Participants with a personal or family history of schizophrenia or psychotic disorders
10. Participants who are pregnant or breast/chest-feeding or plans to become pregnant within the study period or within three months of interventional product discontinuation
11. Participants who cannot commit to using contraception and refraining from recreational cannabis use and driving throughout the study period
12. Participants with known allergy to cannabinoids and/or palm/coconut oil