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                                        Cannabis Studies


These is a listing of various double-blind studies performed using humans.  The cannabis used is full plant extract and not produced sythetically (products such as marinol for example). There are many studies using the double-blind, blind and animal formats. All three formats have concluded the majority of the time that cannabis is indeed safe and provides real medical benefits. There are studies that have shown non conclusive and negative results (nothing is 100%). We have listed but a few of the more powerful and postive study results using the double-blind human study format.




Medicinal cannabis: is delta9-tetrahydrocannabinol necessary for all its effects?


1 The pharmacological potencies of the resins from three different samples of Brazilian marihuana (A, B and C) were determined through corneal areflexia in rabbits, decrease of spontaneous motor activity and induction of catatonia in mice, and decrease of rope climbing performance of rats.2 The Delta(9)-tetrahydrocannabinol (Delta(9) THC) content of the marihuanas, measured by gas chromatography, was 0.82, 2.02 and 0.52%, respectively, for samples A, B and C. Approximately 2% cannabinol was present in samples A and B whereas the content of cannabidiol was approximately 0.1%.3 The petroleum ether extraction of the samples A, B and C yielded, respectively, 12.06, 14.56 and 4.26% of resin.4 In all animal tests resin B was nearly twice as active as resin A, whereas C was the weakest.5 The smoke of the marihuana samples was inhaled by 33 human subjects, under a double-blind standardized procedure. Pulse rate, a time production task and an evaluation of psychological effects were recorded.6 The smoke of 250 mg of sample B provoked disruption of the time production task, increased pulse rate, and induced strong psychological reactions in four of the six subjects who received it. Similar effects, although slightly smaller, were obtained with 500 mg of sample A. On the other hand, 500 mg of sample C did not differ from placebo.7 It is suggested that it is possible by means of animal tests to predict the potency of a marihuana sample in man.8 In parallel experiments, Delta(9)-THC was administered to other human subjects and to laboratory animals in a manner similar to that in which the marihuana samples were administered.9 Comparison of the results between the marihuanas and Delta(9)-THC showed that in man and in the laboratory animals marihuanas A and B induced effects two to four times greater than expected from their Delta(9)-THC content.10 It is suggested that there may be potentiation of the effects of Delta(9)-THC by other substances present in these marihuana samples.



Centre for Pharmacognosy and Phytotherapy, School of Pharmacy, University of London, 29/39 Brunswick Square, London WC1N 1AX, UK. December 2003





Derick T. Wade, MD, Professor in the Department of Clinical Neurology at the University of Oxford, et al., wrote in a Feb. 2003 article titled "A Preliminary Controlled Study to Determine Whether Whole-Plant Cannabis Extracts Can Improve Intractable Neurogenic Symptoms" in the journal Clinical Rehabilitation:

"OBJECTIVES: To determine whether plant-derived cannabis medicinal extracts (CME) can alleviate neurogenic symptoms unresponsive to standard treatment, and to quantify adverse effects...

Measures used: Patients recorded symptom, well-being and intoxication scores on a daily basis using visual analogue scales. At the end of each two-week period an observer rated severity and frequency of symptoms on numerical rating scales, administered standard measures of disability (Barthel Index), mood and cognition, and recorded adverse events.

RESULTS: Pain relief associated with both THC and CBD was significantly superior to placebo. Impaired bladder control, muscle spasms and spasticity were improved by CME in some patients with these symptoms. Three patients had transient hypotension and intoxication with rapid initial dosing of THC-containing CME.

CONCLUSIONS: Cannabis medicinal extracts can improve neurogenic symptoms unresponsive to standard treatments. Unwanted effects are predictable and generally well tolerated. Larger scale studies are warranted to confirm these findings."



Feb. 2003
Clinical Rehabilitation





Jonathan S. Berman, MA, Consulting Anaesthetist at the Royal National Orthopaedic Hospital, et al., wrote the following in a Dec. 2004 article titled "Efficacy of Two Cannabis Based Medicinal Extracts for Relief of Central Neuropathic Pain from Brachial Plexus Avulsion: Results of a Randomised Controlled Trial" in the journal Pain:

"The objective was to investigate the effectiveness of cannabis-based medicines for treatment of chronic pain associated with brachial plexus root avulsion. This condition is an excellent human model of central neuropathic pain as it represents an unusually homogenous group in terms of anatomical location of injury, pain descriptions and patient demographics...

The primary outcome measure was the mean pain severity score during the last 7 days of treatment. Secondary outcome measures included pain related quality of life assessments. The primary outcome measure failed to fall by the two points defined in our hypothesis. However, both this measure and measures of sleep showed statistically significant improvements.

The study medications were generally well tolerated with the majority of adverse events, including intoxication type reactions, being mild to moderate in severity and resolving spontaneously. Studies of longer duration in neuropathic pain are required to confirm a clinically relevant, improvement in the treatment of this condition."



Dec. 2004





Mark A. Ware, MD, MSc, et al., stated the following in their Aug. 30, 2010 study titled "Smoked Cannabis for Chronic Neuropathic Pain: A Randomized Controlled Trial," published in the Canadian Medical Association Journal:

"Adults with post-traumatic or postsurgical neuropathic pain were randomly assigned to receive cannabis at four potencies (0%, 2.5%, 6% and 9.4% tetrahydrocannabinol) over four 14-day periods in a crossover trial. Participants inhaled a single 25-mg dose through a pipe three times daily for the first five days in each cycle, followed by a nine-day washout period. Daily average pain intensity was measured using an 11-point numeric rating scale.


A single inhalation of 25 mg of 9.4% tetrahydrocannabinol herbal cannabis three times daily for five days reduced the intensity of pain, improved sleep and was well tolerated."



Aug. 30, 2010
Canadian Medical Association Journal






Jeremy R. Johnson, MBChB, Medical Director at the Shropshire and Mid Wales Severn Hospice, et. al, wrote the following in a Nov. 2009 article titled "Multicenter, Double-Blind, Randomized, Placebo-Controlled, Parallel-Group Study of the Efficacy, Safety, and Tolerability of THC:CBD Extract and THC Extract in Patients With Intractable Cancer-Related Pain," published on theJournal of Pain and Symptom Management website:

"The primary analysis of change from baseline in mean pain Numerical Rating Scale (NRS) score was statistically significantly in favor of THC:CBD compared with placebo...

This study shows that THC:CBD extract is efficacious for relief of pain in patients with advanced cancer pain not fully relieved by strong opioids."


Nov. 6, 2009
Journal of Pain and Symptom Management






Alena Novotna, MD, et al., stated the following in their Mar. 1, 2011 study titled "A Randomized, Double-blind, Placebo-controlled, Parallel-group, Enriched-design Study of Nabiximols (Sativex), as Add-on Therapy, in Subjects with Refractory Spasticity Caused by Multiple Sclerosis," published in the European Journal of Neurology:

"Spasticity is a disabling complication of multiple sclerosis, affecting many patients with the condition. Subjects were treated with nabiximols [Sativex], as add-on therapy, in a single-blind manner... This study has shown Sativex to improve spasticity in patients who had failed


Mar. 1, 2011
European Journal of Neurology






Ronald J. Ellis, MD, PhD, Professor In Residence in the Department of Neuroscience at the University of California at San Diego, et al., stated the following in their Aug. 2008 study titled "Smoked Medicinal Cannabis for Neuropathic Pain in HIV: A Randomized, Crossover Clinical Trial," published in Neuropsychopharmacology:

"In a double-blind, randomized, clinical trial of the short-term adjunctive treatment of neuropathic pain in HIV-associated distal sensory polyneuropathy, participants received either smoked cannabis or placebo cannabis cigarettes...

Among completers, pain relief was significantly greater with cannabis than placebo. The proportion of subjects achieving at least 30% pain relief was again significantly greater with cannabis (46%) compared to placebo (18%). It was concluded that smoked cannabis was generally well-tolerated and effective when added to concomitant analgesic therapy in patients with medically refractory pain due to HIV-associated neuropathy."


Aug. 2008






Barth Wilsey, MD, Director of the University of California at Davis Analgesic Research Center, et al., stated the following in their June 2008 study titled "A Randomized, Placebo Controlled Cross-Over Trial of Cannabis Cigarettes in Neuropathic Pain," published in the Journal of Pain:

"This study's objective was to examine the efficacy of two doses of smoked cannabis on pain in persons with neuropathic pain of different origins (e.g., physical trauma to nerve bundles, spinal cord injury, multiple sclerosis, diabetes). In a double-blind, randomized clinical trial participants received either lowdose, high-dose, or placebo cannabis cigarettes...

Thirty-eight patients underwent a standardized procedure for smoking either high-dose (7%), low-dose (3.5%), or placebo cannabis; of these, 32 completed all three smoking sessions. The study demonstrated an analgesic response to smoking cannabis with no significant difference between the low and the high dose cigarettes. The study concluded that both low and high cannabis doses were efficacious in reducing neuropathic pain of diverse causes."


June 2008
Journal of Pain







Christine Collin, MD, Senior Consultant in Neuro-rehabilitation at the Royal Berkshire and Battle Hospitals, et al., wrote the following in their article "Randomized Controlled Trial of Cannabis-Based Medicine in Spasticity Caused by Multiple Sclerosis," published in the Mar. 2007 European Journal of Neurology:

 "Symptoms relating to spasticity are common in multiple sclerosis (MS) and can be difficult to treat. We have investigated the efficacy, safety and tolerability of a standardized ... cannabis-based medicine (CBM) containing delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD), upon spasticity in MS. A total of 189 subjects with definite MS and spasticity were randomized to receive daily doses of active preparation (n = 124) or placebo (n = 65) in a double blind study over 6 weeks...

The primary efficacy analysis... showed the active preparation to be significantly superior...

We conclude that this CBM [cannabis-based medicine] may represent a useful new agent for treatment of the symptomatic relief of spasticity in MS."


Mar. 2007
European Journal of Neurology








Donald Abrams, MD, Professor of Clinical Medicine at the University of California at San Francisco, et al. wrote in their Feb. 13, 2007 article titled "Cannabis in Painful HIV-Associated Sensory Neuropathy: A Randomized Placebo-Controlled Trial" in the journal Neurology:

"Objective: To determine the effect of smoked cannabis on the neuropathic pain of HIV-associated sensory neuropathy, and an experimental pain model...

Patients were randomly assigned to smoke either cannabis (3.56% thc) or identical placebo cigarettes with the cannabinoids extracted three times daily for 5 days...

Conclusion: Smoked cannabis was well tolerated and effectively relieved chronic neuropathic pain from HIV-associated sensory neuropathy The findings are comparable to oral drugs used for chronic neuropathic pain."



Feb. 13, 2007






David J. Rog, PhD, from the Walton Centre for Neurology and Neurosurgery at the University of Liverpool, et al., wrote in a Sep. 2005 article titled "Randomized, Controlled Trial of Cannabis-Based Medicine in Central Pain in Multiple Sclerosis" in the journal Neurology:

"BACKGROUND: Central pain in multiple sclerosis (MS) is common and often refractory to treatment...

CONCLUSIONS: Cannabis-based medicine is effective in reducing pain and sleep disturbance in patients with multiple sclerosis related central neuropathic pain and is mostly well tolerated."


Sep. 2005







Derick T. Wade, MD, Professor in the Department of Clinical Neurology at the University of Oxford, et al., wrote the following in an Aug. 2004 article titled "Do Cannabis-based Medicinal Extracts Have General Or Specific Effects on Symptoms in Multiple Sclerosis? A Double-blind, Randomized, Placebo-controlled Study on 160 Patients," published in the journal Multiple Sclerosis:

"The primary outcome measure was a Visual Analogue Scale (VAS) score for each patient's most troublesome symptom. Additional measures included VAS scores of other symptoms, and measures of disability, cognition, mood, sleep and fatigue. Following CBME the primary symptom score reduced from mean (SE) 74.36 (11.1) to 48.89 (22.0) following CBME and from 74.31 (12.5) to 54.79 (26.3) following placebo [ns]. 

Spasticity VAS scores were significantly reduced by CBME (Sativex) in comparison with placebo (P=0.001). There were no significant adverse effects on cognition or mood and intoxication was generally mild." 



Aug. 2004
Multiple Sclerosis






Claude Vaney, MD, Medical Director of the Neurological Rehabilitation and MS Centre, Montana, Switzerland, et al., wrote in an Aug. 2004 article titled "Efficacy of Tetrahydrocannabinol in Patients Refractory to Standard Antiemetic Therapy. Efficacy, Safety and Tolerability of an Orally Administered Cannabis Extract in the Treatment of Spasticity in Patients with Multiple Sclerosis: A Randomized, Double-blind, Placebo-controlled, Crossover Study" in the journal Multiple Sclerosis:

"In the 50 patients included into the intention-to-treat analysis set, there were no statistically significant differences associated with active treatment compared to placebo, but trends in favour of active treatment were seen for spasm frequency, mobility and getting to sleep.

In the 37 patients (per-protocol set) who received at least 90% of their prescribed dose, improvements in spasm frequency (P = 0.013) and mobility after excluding a patient who fell and stopped walking were seen (P = 0.01). Minor adverse events were slightly more frequent and severe during active treatment, and toxicity symptoms, which were generally mild, were more pronounced in the active phase.

CONCLUSION: A standardized Cannabis sativa plant extract might lower spasm frequency and increase mobility with tolerable side effects in MS patients with persistent spasticity not responding to other drugs."



Aug. 2004
Multiple Sclerosis


SOURCES: Internet, medical journals, ProCon, wikipedia)



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