The objective of the current study is to prospectively assess the effect of cannabis on pain and functional outcomes in a large group of patients with chronic pain.

This is a prospective, observational, open-label study carried out at the ambulatory pain clinic of Hadassah-Hebrew University Medical Center Pain Relief Unit.

Study population: Patients suffering from chronic pain that has not been relieved with other analgesic medications, who are eligible for treatment with medical cannabis (cigarettes, oil or cookies) following approval of Israeli Ministry of health.The patients will receive a prescription to be dispensed at pre-approved cannabis distribution points by a certified provider.

In this study, the efficacy of the cannabis treatment on pain and related quality of life (QoL) outcomes will be assessed by administering the S-TOPS questionnaire (Haroutiunian, Pain 2012), and the Brief Pain Inventory (BPI) before the treatment (baseline), and on expected follow-up visits at approximately 6 and 12 months.

Inclusion Criteria:

• Age >18 years old
• Chronic pain, with duration of 3 months or longer
• Lack of satisfactory analgesic response or intolerable adverse effects with at least two analgesics from 2 different drug classes at full dose.

Exclusion Criteria:

• Inability to read and understand the informed consent form.
• History of drug abuse/dependence
• Psychiatric co morbidity (or history) of schizophrenia or acute psychosis.
• Family history of schizophrenia.
• Psychologist evaluation of high abuse risk.

Chronic pain patients with lack of satisfactory analgesic response or intolerable adverse effects with at least two analgesics from 2 different drug classes at full dose. Eligible for cannabis treatment following Israeli Ministry of Health approval.