No evidence that cannabinoids are effective in the improvement of disturbed behaviour in dementia or in the treatment of other symptoms of dementia

Krishnan S, Cairns R, Howard R

Published Online:

April 15, 2009

Cannabinoids are compounds derived from the cannabis plant (Cannabis sativa). Laboratory studies have indicated that cannabinoids may regulate some of the processes that lead to neurodegeneration. This suggests that cannabinoids could be useful in the treatment of neurodegenerative dementias such as Alzheimer's disease. So far, only one small randomized controlled trial has assessed the efficacy of cannabinoids in the treatment of dementia. This study had poorly presented results and did not provide sufficient data to draw any useful conclusions.

Abstract (click to read)

Background:

Following the discovery of an endogenous cannabinoid system and the identification of specific cannabinoid receptors in the central nervous system, much work has been done to investigate the main effects of these compounds. There is increasing evidence that the cannabinoid system may regulate neurodegenerative processes such as excessive glutamate production, oxidative stress and neuroinflammation. Neurodegeneration is a feature common to the various types of dementia and this has led to interest in whether cannabinoids may be clinically useful in the treatment of people with dementia. Recent studies have also shown that cannabinoids may have more specific effects in interrupting the pathological process in Alzheimer's disease.

Objectives:

To determine from available research whether cannabinoids are clinically effective in the treatment of dementia.

Search strategy:

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 11 April 2008 using the terms: cannabis or cannabinoid* or endocannabinoid* or cannabidiol or THC or CBD or dronabinol or delta-9-tetrahydrocannabinol or marijuana or marihuana or hashish. The CDCIG Specialized Register contains records from all major health care databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many clinical trials registries and grey literature sources.

Selection criteria:

All double-blind and single (rater)-blind randomized placebo controlled trials assessing the efficacy of cannabinoids at any dose in the treatment of people with dementia.

Data collection and analysis:

Two reviewers independently examined the retrieved studies for inclusion according to the selection criteria. They then independently assessed the methodological quality of selected trials and extracted data where possible.

Main results:

Only one study met the inclusion criteria. The data in the study report were presented in such a way that they could not be extracted for further analysis and there was insufficient quantitative data to validate the results.

Authors' conclusions:

This review finds no evidence that cannabinoids are effective in the improvement of disturbed behaviour in dementia or in the treatment of other symptoms of dementia. More randomized double-blind placebo controlled trials are needed to determine whether cannabinoids are clinically effective in the treatment of dementia.

This record should be cited as:

Krishnan S, Cairns R, Howard R. Cannabinoids for the treatment of dementia. Cochrane Database of Systematic Reviews 2009, Issue 2. Art. No.: CD007204. DOI: 10.1002/14651858.CD007204.pub2

Assessed as up to date:

November 10, 2008

Find the research

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Primary Review Group:

Dementia and Cognitive Improvement Group

PEARLS - Practical Evidence About Real Life Situations (click to read)

Clinical question:

Are cannabinoids clinically effective in the treatment of dementia?

Bottom line:

There was no evidence that cannabinoids are effective in the improvement of disturbed behaviour in dementia or in the treatment of other symptoms of dementia. Only 1 small study was included which was designed to focus on the effects of the cannabinoid dronabinol on anorexia in Alzheimer's disease. While improvement of anorexia is clearly an important outcome for patients and their carers, it was not a primary outcome of interest in this review. The study concluded that the cannabinoid dronabinol may be useful in the treatment of anorexia and to improve disturbed behaviour in people with Alzheimer's disease.

Caveat:

Only 1 small study met the inclusion criteria. The lack of quantitative data and the unclear risk of bias in key domains of this study mean no useful conclusions can be drawn from this review.

Context:

There is increasing evidence the cannabinoid system may regulate neurodegenerative processes, such as excessive glutamate production, oxidative stress and neuroinflammation. Neurodegeneration is a feature common to the various types of dementia and this has led to interest in whether cannabinoids may be clinically useful in the treatment of people with dementia. Recent studies have also shown cannabinoids may have more specific effects in interrupting the pathological process in Alzheimer's disease.

Cochrane Systematic Review:

Krishnan S et al. Cannabinoids for the treatment of dementia. Cochrane Reviews 2009, Issue 2. Article No. CD007204. DOI: 10.1002/14651858.CD007204.pub2. This review contains 1 study involving 15 participants.

Authored by:

Brian R McAvoy

Cochrane Primary Health Care Field

Health topics:

Mental health > Dementia & cognition > Interventions aimed at causes of the disease

Mental health > Dementia & cognition > Interventions aimed at manifestations of the disease

Neurology > Dementia & cognition > Interventions aimed at manifestations of the disease

Neurology > Dementia & cognition > Treatment aimed at causes of the disease

Complementary & alternative medicine > Mental health > Dementia & cognition

Complementary & alternative medicine > Neurology > Dementia & cognition

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

No evidence that cannabinoids are effective in the improvement of disturbed behaviour in dementia or in the treatment of other symptoms of dementia

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