There are first studies on a therapeutic effect of cannabinoid drugs in the sense of a specific positive effect on ADHD symptoms.
In terms of cognitive performance and activity level, a slight but non-significant improvement was observed with Sativex. Hyperactivity/impulsivity (p=0.03) and cognitive inhibition (p=0.05) were significantly improved, and inattention (p=0.10) and emotional lability (p=0.11) tended to improve, although significance was lost after statistical adjustment for multiple testing. One serious (muscle seizures/convulsions) and three mild side effects occurred in the active group and one serious side effect (cardiovascular problems) in the placebo group.
The study concluded that cannabis medication may reduce ADHD symptoms for some adults with ADHD without cognitive impairment. A comprehensive meta-study found insufficient evidence for efficacy in ADHD.
One study found a correlation between high doses of cannabinol (CBN) and reduced self-reported ADHD symptoms, as well as a correlation between high doses of medical cannabis and a reduction or complete substitution of other ADHD medications.
A comprehensive discussion of THC medications for ADHD can be found at ADHSpedia.
1. Cannabinoid receptors¶
There are two cannabinoid receptors.
1.1. CB1 receptor¶
The CB1 receptor (cannabinoid-1 receptor) is one of the most abundant receptors in the brain. It is present in many organs, sometimes in low concentrations.
The CB1 receptor is involved in the regulation of:
- Movement coordination
- Spatial orientation
- Sensory perception (taste, smell, touch, hearing)
- Mental performance
-
Motivation
- Pain
- Diclofenac inhibits pain via CB1 receptors, GPR55 receptors, and mu-opioid receptors of mPFC and ventrolateral periaqueductal gray in brainstem
-
Inhibition of excessive signal transduction by neurotransmitters.
Activated CB1 receptors:
- inhibit GABA neurons, resulting in less inhibition of dopamine neurons. Thus, cannabinoids indirectly increase dopamine levels
- inhibit overactivity of pain regulation and thus have an analgesic effect
- THC as a CB1 agonist increases dopamine in the nucleus accumbens. Adenosine A2A receptor antagonists (e.g., caffeine) counteract this effect.
Since the CB1 receptor is not present in the brainstem, which regulates breathing and the cardiovascular system, an overdose of THC should not be able to cause deaths associated with it.
1.2. CB2 receptor¶
The CB2 receptor (cannabinoid-1 receptor) is primarily associated with the immune system.
2. Cannabis medication for ADHD¶
In Germany, Sativex, Cannabis Flos, Canemes, and Dronabinol are several cannaboid medications approved, but not for ADHD. For an off-label use in ADHD, an exemption had to be applied for at the BfArM in the past. Since 2017, a medical prescription of Sativex as well as Cannabis Flos for ADHD is permitted under the BtmG without an additional exemption.
As of 2017, about 150 ADHD sufferers had received waivers (out of a total of 1061 granted).
We now know of a double-digit number of reports from sufferers, as well as several sufferers personally, in whom medical cannabis has significantly reduced ADHD symptoms after MPH and amphetamine medications had failed to adequately address them.
In a case of an apparently massive THC addict who is allowed to consume THC in a controlled manner, it is open whether this is based on the same effect or whether the effect is explained by the fact that the THC has merely eliminated the withdrawal symptoms of an existing THC addiction. This pattern is also known in alcohol addicts who function “better” with their base dose because the withdrawal symptoms are masked.
In summary:
Cannabinoid medications may be prescribed in Germany for ADHD as a BtM prescription (like stimulants) if other medications are ineffective. Health insurance companies usually reimburse the costs upon application.
3. Effect of THC on dopamine¶
THC indirectly increases dopamine levels in the brain.
The THC cannabinoids do not act directly on dopamine neurons, but on the endocannabinoid system. Cannabinoid receptors are found in many brain areas that have dopamine neurons. Dopamine neurons themselves do not have cannabinoid receptors. However, dopamine neurons are inhibited by GABA neurons, which in turn have cannabinoid receptors.
THC activates CB1 receptors on GABA neurons, which inactivate the GABA neurons. Thus, the GABA neurons that inhibit the dopamine neurons are deactivated. As a result, the dopamine neurons are less inhibited and thus more active.
THC as a CB1 agonist increases dopamine in the nucleus accumbens. Adenosine A2A receptor antagonists (e.g., caffeine) counteract this effect.
For the difference between medications and drugs, see ⇒.. Medications and drugs - the difference.
4. Inhibition of sensory overload¶
Endocannabinoids (cannabinoids produced naturally in the body) also act on the CB1 receptors, causing, among other things, protection against stimulus overload.
5. CBD-containing cannabis extract for ASD, anxiety and ADHD¶
One study treated a small group of ASD sufferers with a CBD-enriched cannabis extract. The CBD to THC content was 75 to 1. Almost all sufferers found improvements after 6 to 9 months, often improving ADHD symptoms. Improvements were most pronounced in nonepileptic sufferers.
One review reports positive effects of cannabidiol in ADHD
A single dose showed no change in ADHD or attention symptoms in mice, but did reduce anxiety symptoms.
Several sufferers told us that CBD oil (without THC) did not improve their ADHD symptoms.
However, a significant improvement was reported in anxiety disorders. Several sufferers reported that CBD oil enabled them to significantly reduce the previous dosage of their anxiety medication.
6. Cannabis treatment for tic disorders¶
A small study looked at the treatment of tic disorders with cannabis. Tics were found to improve by 60% in 85% of those affected, comorbidities (most commonly OCB / OCD, ADHD, and sleep disorders) improved in 55%, and quality of life improved in 93%. The effects were estimated to be long-term. Half reported side effects, although their severity was judged to be tolerable. THC-rich strains seemed to work better.
Tic disorders share a genetic basis with ADHD.
7. Dosage and application instructions for medical cannabis¶
Instructions on how to dose medical cannabis (Cannabis Flos) using a vaporizer can be found here.
