Cannabis and cannabinoids
Effects of cannabis on cognition in patients with MS: A psychometric and MRI study.
OBJECTIVE: To determine functional and structural neuroimaging correlates of cognitive dysfunction associated with cannabis use in multiple sclerosis (MS).
METHODS: In a cross-sectional study, 20 subjects with MS who smoked cannabis and 19 noncannabis users with MS, matched on demographic and neurologic variables, underwent fMRI while completing a test of working memory, the N-Back. Resting-state fMRI and structural MRI data (lesion and normal-appearing brain tissue volumes, diffusion tensor imaging metrics) were also collected. Neuropsychological data pertaining to verbal (Selective Reminding Test Revised) and visual (10/36 Spatial Recall Test) memory, information processing speed (Paced Auditory Serial Addition Test [2- and 3-second versions] and Symbol Digit Modalities Test), and attention (Word List Generation) were obtained.
RESULTS: The cannabis group performed more poorly on the more demanding of the Paced Auditory Serial Addition Test tasks (i.e., 2-second version) (p < 0.02) and the 10/36 Spatial Recall Test (p < 0.03). Cannabis users had more diffuse cerebral activation across all N-Back trials and made more errors on the 2-Back task (p < 0.006), during which they displayed increased activation relative to nonusers in parietal (p < 0.007) and anterior cingulate (p < 0.001) regions implicated in working memory. No group differences in resting-state networks or structural MRI variables were found.
CONCLUSIONS: Patients with MS who smoke cannabis are more cognitively impaired than nonusers. Cannabis further compromises cerebral compensatory mechanisms, already faulty in MS. These imaging data boost the construct validity of the neuropsychological findings and act as a cautionary note to cannabis users and prescribers.
Pavisian B1, Macintosh BJ, Szilagyi G, Staines RW, O'Connor P, Feinstein A.
Sources: Neurology. 2014 Apr 30. [Epub ahead of print] & Pubmed PMID: 24789863 (06/05/14)
Cannabis may help with some MS symptoms(29/04/14)
Cannabis sprays and tablets can improve some symptoms of multiple sclerosis, a study shows. But the effect of cannabis on epilepsy and other brain conditions is less clear, and side effects are common.
What do we know already?
Cannabis (also called marijuana) contains around 60 chemicals that affect the brain. Some of these chemicals cause the ‘high’ that people get when they use cannabis as an illegal drug. But these chemicals can also have other effects, which may be helpful for conditions that affect the brain and nervous system, such as multiple sclerosis (MS), Parkinson’s disease, and epilepsy.
Some people smoke cannabis to help with these conditions. Researchers have also developed mouth sprays and tablets with cannabis extracts. Sprays and tablets don’t have some of the health risks associated with smoking cannabis, such as lung diseases.
However, it’s not clear how well any of these forms of cannabis work for people with these medical conditions, as studies have had different results.
How was the new study done?
Researchers searched for the best studies done so far on the effects of cannabis on several conditions affecting the brain and nervous system. These included multiple sclerosis, Huntington’s disease, Tourette’s syndrome, cervical dystonia (abnormal neck movements), and epilepsy. They also searched for studies on using cannabis to help with the movement problems (called dyskinesias) caused by treatment for Parkinson’s disease. They then summarised the studies’ results, to see what conclusions they might draw.
What does the new study say? The researchers found 34 studies in total. Several of these looked at using cannabis for multiple sclerosis. Overall, they found that cannabis sprays and tablets improved some symptoms, including twitching muscles (spasms) and some types of pain (such as pain related to spasms). Cannabis sprays also seemed to help with bladder problems causing people to urinate often. However, cannabis sprays and tablets did not help with tremors (this is when a part of the body shakes).
There wasn’t enough research to say whether cannabis treatments might help with Huntington’s disease, Tourette’s syndrome, cervical dystonia, and epilepsy. However, the research did suggest that cannabis tablets do not help with movement problems caused by treatment for Parkinson’s disease.
Most of the studies looked at taking cannabis by sprays or tablets. There were few useful studies looking at whether smoking cannabis in pipes or cigarettes helped with symptoms.
Many people had side effects when using cannabis. These included weakness, feeling sick, mood changes, dizziness, fatigue, thoughts of suicide, and hallucinations. Overall about 7 in every 100 people using cannabis stopped their treatment because of side effects, compared with 2 in every 100 people using a dummy (placebo) treatment.
Studies also suggested that people with multiple sclerosis were more likely to have a worsening of their thinking abilities (cognitive declines) if they used cannabis.
How reliable is the research?
This review of studies should provide an accurate summary of what the current research tells us. The findings on using cannabis tablets and sprays for multiple sclerosis should be reliable, as these were based on several good-quality studies.
However, we need much more research to know whether cannabis treatments are effective and safe for the other conditions. We also need studies that compare cannabis with other treatments for these conditions.
What does this mean for me?
If you have multiple sclerosis, these findings suggest that cannabis sprays and tablets may improve some of your symptoms. But you need to weigh these possible improvements against the chance of side effects. It is also illegal to possess most kinds of cannabis in the UK, although a cannabis spray called Sativex is available on prescription.
If you have epilepsy, Huntington’s disease, Tourette’s syndrome, or cervical dystonia, we don’t yet have enough research to know whether cannabis treatments are helpful or safe. However, if you have movement problems caused by treatment for Parkinson’s disease, studies do suggest that cannabis tablets are unlikely to help.
Source: WebMD ©2009-2014 WebMD UK Limited and Boots UK Limited (29/04/14)
AAN endorses cannabis for MS(27/03/14)
The American Academy of Neurology has issued new evidence-based complementary and alternative medicine guidelines for multiple sclerosis.
HealthDay News -- The American Academy of Neurology is recommending oral cannabis extract to help ease spasticity symptoms and pain in patients with multiple sclerosis, along with other therapies, in new evidence-based complementary and alternative medicine (CAM) recommendations.
Vijayshree Yadav, MD, of the Oregon Health & Science University in Portland, and other members of the AAN's Guideline Development Subcommittee, conducted a literature search to develop the recommendations, which are published online in Neurology.
Clinicians may offer oral cannabis extract (Level A) or tetrahydrocannabinol (Level B) for spasticity symptoms and pain (excluding central neuropathic pain), but should counsel patients that these agents are probably ineffective for objective spasticity (short-term)/tremor (Level B) and possibly effective for spasticity and pain (long-term; Level C).
Sativex oromucosal cannabinoid spray (nabiximols) can be suggested for spasticity symptoms, pain and urinary frequency (Level B), but clinicians should counsel patients that these agents are probably ineffective for objective spasticity/urinary incontinence (Level B). Furthermore, the spray is not currently FDA-approved and is unavailable in the United States, the researchers noted.
"In the United States, caution should be exercised with regard to extrapolation of results of trials of standardized oral cannabis extracts (which are unavailable commercially) to other nonstandardized, nonregulated cannabis extracts (which may be commercially available in states with medical marijuana laws)," Yadav and colleagues wrote.
Magnetic therapy is probably effective for fatigue, but probably ineffective for depression (Level B). Among common supplements, clinicians can counsel patients that fish oil is probably ineffective for relapses, disability, fatigue, magnetic resonance imaging lesions, and quality of life (Level B). Ginkgo biloba is ineffective for cognition (Level A), but possibly effective for fatigue (Level C). Reflexology is possibly effective for paresthesia (Level C).
Possibly ineffective therapies (Level C) include Cari Loder for disability, depression and fatigue, and bee sting therapy for relapses, disability, fatigue and lesion burden/volume.
"Clinicians should exercise caution regarding standardized versus nonstandardized cannabis extracts and overall CAM quality control/nonregulation," the researchers wrote. "Safety/efficacy of other CAM/CAM interaction with MS disease-modifying therapies is unknown."
Reference 1.Yadav V et al. Neurology. 2014; 82(12): 1083-1092.
Source: Copyright © 2014 Haymarket Media, Inc. All Rights Reserved (27/03/14)