June 28, 2007 - New York -- Smoked marijuana produces "substantial and comparable increases in food intake ... with little evidence of discomfort and no impairment of cognitive performance"

Inhaling cannabis significantly increases daily caloric intake and body weight in HIV-positive patients, is well tolerated, and does not impair subjects' cognitive performance, according to clinical trial data to be published in the Journal of Acquired Immune Deficiency Syndromes (JAIDS).

Investigators at Columbia University in New York assessed the efficacy of inhaled cannabis and oral THC (Marinol) in a group of ten HIV-positive patients in a double-blind, placebo-controlled trial. All of the subjects participating in the study had prior experience using marijuana therapeutically and were taking at least two antiretroviral medications.

Researchers reported that smoking cannabis (2.0 or 3.9 percent THC) four times daily "produced substantial ... increases in food intake ... with little evidence of discomfort and no impairment of cognitive performance."

On average, patients who smoked higher-grade cannabis (3.9 percent) increased their body weight by 1.1 kg over a four-day period. Researchers reported that inhaling cannabis increased the number of times subjects ate during the study, but did not alter the average number of calories consumed during each meal.

Investigators said that the administration of oral THC produced similar weight gains in patients, but only at doses that were "eight times current recommendations." The US Food and Drug Administration approved the prescription use of Marinol (a gelatin capsule containing synthetic THC in sesame oil) to treat HIV/AIDS-related cachexia in 1992.

Subjects in the study reported feeling intoxicated after using either cannabis or oral THC, but remarked that these effects were "positive" and "well tolerated."

Although not a primary outcome measure of the trial, authors reported that patients made far fewer requests for over-the-counter medications while taking either cannabis or oral THC than they did when administered placebo. Most of these requests were to treat patients' gastrointestinal complaints (nausea, diarrhea, and upset stomach), investigators said.

Patients in the study also reported that smoking higher-strength marijuana subjectively improved their sleep better than oral THC.

"The data demonstrate that over four days of administration, smoked marijuana and oral [THC] produced a similar range of positive effects: increasing food intake and body weight and producing a 'good [drug] effect' without producing uncomfortable levels of intoxication or impairing cognitive function," authors wrote.

They added, "Smoked marijuana ... has a clear medical benefit in HIV-positive [subjects] by increasing food intake and improving mood and objective and subjective sleep measures."

A previous preliminary trial by Columbia investigators published in the journal Psychopharmacology in 2005 also reported that inhaling cannabis "produce[s] substantial ... increases in food intake [in HIV+ positive patients] without producing adverse effects."

Survey data indicates that an estimated one out of three HIV/AIDS patients in North America use cannabis therapeutically to combat symptoms of the disease or the side-effects of antiretroviral medications.

Clinical trial data published in the Annals of Internal Medicine in 2003 reported that cannabis use by HIV patients is associated with increased CD4/T-cell counts compared to non-users. A separate study published in JAIDS in 2005 found that HIV/AIDS patients who report using medical marijuana are 3.3 times more likely to adhere to their antiretroviral therapy regimens than non-cannabis users.

Most recently, investigators at San Francisco General Hospital and the University of California's Pain Clinical Research Center reported this year in the journal Neurology that inhaling cannabis significantly reduced HIV-associated neuropathy (nerve pain) compared to placebo.

The Columbia University study is one of the first US-led clinical trials to evaluate the efficacy of smoked cannabis to take place in nearly two decades, and it is the first to compare the tolerability and efficacy of smoked marijuana and oral THC in HIV patients.