Cannabis for migraine: CB1, CGRP & studies

Migraines and the endocannabinoid system

Migraines are one of the most common neurological disorders worldwide – in Germany alone, around 15 percent of the population suffer from them. The endocannabinoid system (ECS) plays a central role in pain modulation and neurotransmitter regulation, which are crucial in the development of migraines.

CB1 receptors are found in high density in the trigeminovauscular system – the core pathway of migraine physiology. The trigeminal neuropeptide CGRP (Calcitonin Gene-Related Peptide) is the most important vasoactive mediator of migraine attacks: THC and other cannabinoids inhibit the release of CGRP from trigeminal nerve endings via CB1 activation, which has a direct antinociceptive effect.

In addition, the ECS modulates the release of serotonin (similar to triptans), attenuates cortical spreading depression (CSD) – the electrophysiological origin of the migraine aura – and regulates central sensitization in the trigeminal caudal nerve.

Clinical study overview

CECD: The endocannabinoid deficit in migraine

Ethan Russo coined the hypothesis of clinical endocannabinoid deficiency (CECD) in 2016: Chronic migraine, fibromyalgia and irritable bowel syndrome are characterized by reduced levels of anandamide in the cerebrospinal fluid. These three diseases share a common pathophysiology of central sensitization and tone regulation – and all three respond empirically to cannabinoids.

Anandamide inhibits trigeminal activation: exogenous cannabinoids such as THC could compensate for this deficit, which would explain the clinical observation that cannabis reduces attack frequency in chronic migraine patients more than in episodic migraine.

THC vs CBD: Different mechanisms of action

THC (acute use): CB1 agonism directly inhibits CGRP and substance P, reduces vasogenic inflammation, attenuates nausea via CB1 in the chemoreceptor trigger zone. Onset of action on inhalation 5-10 minutes – relevant for the acute phase.

CBD (prevention): FAAH inhibition → anandamide elevation; 5-HT1A agonism (similar to triptans); TRPV1 desensitization attenuates nociceptive afferents; GPR55 antagonism inhibits CSD spread. CBD has a preventive rather than acute effect.

Entourage effect: The 1:1 ratio THC/CBD (as in Sativex) shows better tolerability in studies than pure THC – CBD alleviates THC-induced anxiety and could have an additional migraine-specific effect via adenosine reuptake inhibition.

Practical application and dosage

Acute application: Inhalation (vaporizer, 170-185°C) enables the fastest onset of action. 1-2 puffs of THC-rich strain (>15% THC, myrcene/linalool terpene profile) at the beginning of the prodromes or aura. Early use is crucial – efficacy is reduced after complete pain relief.

Prevention: CBD oil 25-75 mg daily (sublingual intake), possibly supplemented with low-dose THC in the evening (0.5-2.5 mg). Study data show onset of effect after 4-8 weeks of continuous use.

SHI reimbursement: Migraine is a recognized indication for medical cannabis if conventional therapies (beta-blockers, topiramate, CGRP antibodies) have failed. The application is made via a neurologist with a connection to a pain clinic.

Contraindications and risks

Cannabis-induced headache (rebound): Chronic high-frequency cannabis use can paradoxically lead to an increase in headache frequency – analogous mechanism to medication-overuse headache (MOH). The empirical limit is more than 15 days/month of use.

Trigger risk: Smoking cannabis (cigarette) can act as a migraine trigger due to hypoxia and carbon monoxide – vaporizer completely avoids this problem.

Interactions: Cannabis and triptans together influence the serotonergic tone; increased risk of sedation possible with combination. CYP interactions with valproate/topiramate (CYP2C19) must be observed.

FAQ: Cannabis for migraine

Summary

Cannabis inhibits the release of CGRP via CB1 in migraine, modulates serotonin in a similar way to triptans and can compensate for the postulated endocannabinoid deficit in chronic migraine. Clinical data show attack reductions of 40-56 percent. THC is suitable for acute therapy, CBD is more suitable for prevention. Chronic high consumption can lead to rebound headaches. SHI reimbursement is possible in cases of treatment resistance.