Parkinson’s disease (PD) is one of the great, seemingly incurable plights of humanity. It is a late-onset disorder, usually developing in people over 60, that causes degeneration of the central nervous system, with serious impairments to the motor system. Tremors, muscle rigidity, slowness, difficulties in walking and mild hallucinations are some of the main symptoms of the disease. Depression, anxiety and, ultimately, dementia are all too well-known consequences to the millions of people affected worldwide. Current treatments for this condition are limited in their effectiveness and often come with problematic side-effects.
Leading PD researchers at King’s College in London have recently been exploring the possibility of using the ayahuasca vine—a plant traditionally brewed into a psychedelic tea in the Amazon rainforest—to treat the disease. There are fascinating reasons and some interesting early results for the possibility of ayahuasca helping in the fight against PD.
Firstly, it’s important to understand that the motor symptoms of PD are caused by a decrease in the production of dopamine in the brain’s basal ganglia. This is why the main treatment in the past 50 years has been a precursor of dopamine called levodopa. However, due to its heavy side effects, other medication is often considered. These are usually dopamine agonists, which are less effective, but with milder side effects, or monoamine oxidase B (MAO-B) inhibitors, which stop this enzyme from breaking down dopamine, but are, unfortunately, also handled difficultly by the human body.
Interestingly, the ayahuasca vine (Banisteriopsis caapi) contains a potent inhibitor of MAO enzymes and therefore shares some similarity with some current PD medicines. The vine does not appear to produce the same heavy side-effects that its synthetic versions do. However, given its MAO inhibiting properties, chemicals in ayahuasca, such as harmine, can still present health risks when taken in combination with certain foods.
The psychedelic brew ayahuasca is typically made from boiling two plants. By inhibiting MAOs in the gut, the chemistry of the vine allows the powerful psychedelic molecule DMT from the second plant (Psychotria viridis) to enter the bloodstream. This allows the DMT to pass the blood-brain barrier instead of being broken down, giving ayahuasca its highly sought-after visionary properties.
The addition of DMT-containing plants as an admixture is more associated with the increased interest that this brew has received from the Western world than its original native purpose. Traditionally, ayahuasca brews often did not contain large quantities of the psychedelic agent, but seemingly were being consumed primarily for the healing effects of the MAOIs in the vine. Ayahuasca is referred to as “aya” (soul) – “wasca” (vine) by the Quechuan indigenous society of the Amazon.
Ayahuasca has a history in PD-related research stretching back almost one hundred years. Louis Lewin, a German pharmacologist, looked into using Banisteriopsis caapi as a possible treatment for rigid-akinetic syndromes in the late 1920s. He was successful in isolating a key active agent of the vine, which he named banisterine (now known as harmine), and the subsequent studies showed improvements in rigidity, but inconclusive results with resolving tremor.
Since the 1930s, this substance had not been further tested as treatment for PD. Recently, however, Banisteriopsis caapi has seen renewed interest, this time by one of the most influential names in PD research – Andrew Lees. Professor Lees has since 1969 been fascinated by the life and work of psychonaut extraordinaire and the author of “Naked Lunch”, William Burroughs. Lees adopted Burroughs as his proverbial mentor and, to this day, credits him for the persistence to stick to the medical path Lees had chosen, but become disillusioned with during the course of his studies.
Eventually, Burroughs’ psychedelic adventures in the Amazon inspired Lees to follow in his footsteps. He cites heading to the Colombian rainforest and trying ayahuasca for the first time in his 60s as a revolutionary experience that gave him new insights into his research and disintegrated the blocks that were holding him from advancing.
This adventure resulted in a study he recently co-authored that reports improvements in motor disability in marmosets when harmine is administered. Although the study didn’t find an increase in locomotor activity nor any dyskinetic effects, the team of researchers concluded that Banisteriopsis caapi is “mildly antiparkinsonian” and that it doesn’t interfere with the levodopa-induced response.
In a previous study conducted by a team of Spanish and Ecuadorian researchers, similar conclusions were drawn from the response of mice which were administered with a soluble extract of Banisteriopsis caapi. The treatment seemed to lower anxiety-related behavior, although it did not induce neuroprotective effects concerning dopamine.
Current results indicate that, due to the absence of certain toxicities, harmine may be a beneficial supplement to any ongoing PD therapy. Still, more research is needed to properly verify the safety or the success of ayahuasca as a PD treatment.
Parkinson’s disease effects people all across the world, yet in some places more than others. According to a recent comprehensive meta-analysis, in North America, Europe and Australia, it is almost three times more common for people over 70 to suffer from this affliction than in Asia (a single epidemiological study conducted in South America finds lower prevalence in Buenos Aires; however, this one result cannot be generalized to the Latin American population).
An additional study of the population of USA residents points to a potential genetic reasoning, as the racial distribution is skewed toward Caucasians. Differences in lifestyle appear important, particularly in the levels of stress, which has been implicated in the progression of PD, and possibly is a risk factor in its development. Farmers are more likely to develop PD, which some researchers suggest may be due to pesticide exposure.
There are obviously many factors at play when trying to understand the cause and treatment of PD. A brew long used by indigenous people of the Amazon for healing many disorders has the potential to help alleviate the disease’s effects. While ayahuasca is currently illegal in many parts of the globe, this emerging PD research provides another reason why government authorities that have banned it, and jailed those who use it, need to seriously rethink their approach.