Does marijuana help with Parkinsons Disease?
Nearly half of Parkinson’s disease patients who
have tried marijuana say the drug helped relieve their symptoms, according
to a survey of patients with the degenerative neurological disorder.
Dr. Evzin Ruzicka, an attending neurologist at Charles University in Prague
in the Czech Republic, reported the findings here at the Movement Disorders
Society’s Seventh International Congress of Parkinson’s Disease and
Movement Disorders. Ruzicka is also a consultant at the Prague Movement
“It’s difficult to directly study the medical effects of cannabis in the
Czech Republic, where we conducted our research, because of its illegal
status,” Ruzicka told Reuters Health. “Therefore, we had to conduct
anonymous surveys. To our knowledge, this is the first study to assess the
effect of cannabis on Parkinson’s disease, and our findings suggest it may
alleviate some symptoms.”
Ruzicka and his colleagues chose to investigate marijuana’s effects on
Parkinson’s disease after hearing from several patients that they had tried
the drug and it had helped them.
The investigators asked all patients who were treated for Parkinson’s
disease at their center to complete a questionnaire that asked about
cannabis use and about several Parkinson’s disease symptoms, including
overall symptoms; tremor while at rest; bradykinesia, or slow movement;
muscle rigidity; and dyskinesias, or involuntary movements. Dyskinesias are
caused by levodopa, the mainstay medication in Parkinson’s treatment.
Among the 630 patients to whom the investigators sent questionnaires, 339
(54%) returned them. The responders’ average age was about 66, and they had
had Parkinson’s disease for an average of roughly 9 years. Among the
responders, 25% reported that they had used cannabis. Most had used it
orally, either as fresh or dried leaves.
Within this group, 39 patients (46%) reported that their Parkinson’s
disease symptoms in general were relieved after they started using
cannabis. In terms of specific symptoms, 26 (31%) reported an improvement
in tremor while at rest, and 38 (45%) experienced a relief of bradykinesia.
Relief of muscle rigidity was reported by 32 (38%), and 12 (14%) said they
had an improvement in levodopa-induced dyskinesias.
The respondents reported that the improvement in symptoms occurred an
average of 1.7 months after they had started using cannabis. Patients who
used it for at least three months were more likely to experience symptom
relief than those with shorter experience, the investigators reported.
This delay between the beginning of cannabis use and the relief of symptoms
made it unlikely that the respondents were having a placebo effect, Ruzicka
said. A placebo effect can occur when the individual taking a treatment
experiences a benefit even if the “treatment,” such as a sugar pill,
contains no active ingredients.
They found no relationship between the length of cannabis use and the
effect on involuntary movements. However, daily marijuana users reported
more improvement in their dyskinesias than those using it less often.
The investigators speculated that the effect of cannabis on Parkinson’s
disease symptoms may be due to interaction among cannabis, certain brain
receptors that respond to cannabis and endogenous cannabinoids or
cannabis-like substances within the body.
He and colleagues plan to investigate a relationship between cannabis use
and relief of Parkinson’s disease symptoms by collaborating in further
studies with investigators in the United Kingdom, Ruzicka told Reuters Health.
Scientists hope to use a marijuana-like chemical in the brain to treat Parkinson’s Disease and schizophrenia.
The chemical, known as anandamide, helps to regulate body movement and coordination.
A team from the University of California Irvine believes it can be used to treat diseases which produce uncontrollable movements such as tics and shaking.
The researchers have used anandamide to limit brain activity in rats.
Writing in the journal Nature Neuroscience, they said anandamide interferes with the effects of nerve cells that transmit dopamine, the message-carrying chemical responsible for stimulating movement and other motor behaviour in the brain.
Uncontrolled production of dopamine has been blamed for some of the symptoms of schizophrenia and the nervous tics and outbursts associated with Tourette’s syndrome.
A lack of dopamine is blamed for the shaking and motor hesitation that marks Parkinson’s disease.
The actor Michael J Fox has Parkinson’s Disease
Daniele Piomelli, an associate professor of pharmacology at UCI, said the research had shown for the first time how anandamides work in the brain to produce normal motor activity.
He said: “Patients with schizophrenia and other diseases have reported that marijuana appears to relieve some of their symptoms, but scientists have never found a physiological reason why.
“By understanding how the anandamide system works similarly to marijuana, we can explore new ways to treat these diseases more effectively.”
But Professor Piomelli said cannabis itself did not offer any kind of cure.
“Marijuana doesn’t provide the regulatory effects on dopamine in the brain that we’re looking for,” he said.
Anandamide, named after the Sanskrit word for “bliss and tranquillity,” is used by a network of nerve cells in an area of the brain called the striatum, which coordinates body movements and other motor behaviour, the researchers said.
Normally nerve cells regulate this behaviour by releasing anandamides at the same time they release dopamine.
The anandamides bind to cannabinoid receptors, which are where tetrahydrocannabinol (THC), the active ingredient in marijuana, docks onto cells.
When the team blocked these receptors, rats experienced severe nervous tics and other uncontrolled motor activity.
Professor Piomelli said new drugs that mimic the effects of anandamides could offer gentler treatments for some diseases.
He said: “Current drugs certainly halt the actions of dopamine, but the side effects, including sedation and dizziness, are very severe,” he said.
In a commentary, Professor David Self of Yale University said the approach could be used to develop drugs that help Parkinson’s treatments, which try to boost production of dopamine in the brain but whose effects wear off after a few years.
Drugs that stimulate the cannabinoid receptor might also be used against Huntington’s disease, a fatal and incurable disease first marked by jerks and spasms, Professor Self added.