This cohort study evaluated marijuana use and related reasons for use every six months over 16 years in a large multi-site study of HIV-infected women in the United States. The study demonstrates that marijuana use is common among HIV-infected women in the U.S., including both recreational and medicinal marijuana use. While the prevalence of marijuana use decreased during study follow-up as participants aged, an increasing proportion of HIV-infected women using marijuana in the study also began using marijuana daily. These heavy users reported using marijuana primarily for medicinal purposes, suggesting the rationale for marijuana use among HIV-infected women in this HAART era study may have changed from purely recreational to a combination of recreational and medicinal usage.
The prevalence of current marijuana use in this multi-center cohort of HIV-infected women in the U.S. was similar to that reported in several other U.S. studies12, 29
, although it was lower than a Canadian study which reported 43% of HIV-infected participants used marijuana recently.30
A previous study of marijuana use in this same WIHS cohort had a lower prevalence of current marijuana use than this study because they had excluded women with an history of daily marijuana use before study baseline.16
The increasing use of medical marijuana among HIV-infected women in this study is consistent with previous studies showing medicinal use in the majority of HIV-infected marijuana users.12, 29, 30
In the most recent data in this study, some medicinal marijuana use was reported by 55% of current marijuana users, similar to other U.S. studies which reported medical use in 45–67% of HIV-infected marijuana users.29, 30
Despite high rates of recreational marijuana use, current rates of medically-prescribed marijuana use remained uncommon overall, reported by 7.1% of HIV-infected women in 2010 in the current study; other studies reported a higher prevalence (10–29%) of current medicinal marijuana use among HIV-infected individuals 3, 11, 29–31
, but this may in part be explained by our definition of medicinal marijuana use as being prescribed by a doctor. Many women who reporting using marijuana that was not medically prescribed, indicated relief of HIV-related symptoms or increasing appetite as a motivator for use (i.e. self prescribed medicinal usage).
There was substantial variation in marijuana use between the six U.S. study sites. These differences may reflect differing state laws and availability of any marijuana and medically prescribed marijuana. In California, which had the highest prevalence and increase in medicinal marijuana use during the study, medical marijuana became legal in 1996. Medicinal marijuana was not legalized in the other states in this study during the study period, although in D.C. medicinal marijuana did become legal in 2010. A recent study suggested that states with legal medical marijuana use have a higher prevalence of marijuana use, but that the percent of marijuana users with marijuana dependence/abuse was similar in states with and without laws allowing medical marijuana use.14
However variation in study recruitment strategies between sites may also contribute to the observed differences as some venue based recruitment may have targeted drug users at risk for HIV-infection.
Reported reasons for marijuana use were similar to previous studies, with stress reduction and appetite stimulation as the most commonly reported reasons for use.29, 30
While many women report using marijuana for social and relaxation reasons, marijuana use for symptom relief was also noted as an important motivator among these HIV-infected women. Reasons for marijuana use in this study were also consistent with previously reported studies showing appetite stimulation, reduction of pain, relaxation/social use, anxiety reduction, and help with sleep.4, 29, 30, 32
Research supports the utility of marijuana in reducing these symptoms with improvements in appetite, nausea, anxiety, depression, tingling, weight loss and tiredness reported from marijuana use in other observational studies of HIV-infected individuals3, 11, 30
. If cannabanoids are proven to reduce these ART-related side effects, medicinal marijuana use may become an increasingly important option for HIV-infected individuals, where laws allow its use. Indeed, recent randomized placebo controlled trials of HIV-infected individuals demonstrated significant reduction in neuropathy-associated pain7, 8
and improved appetite33, 34
from smoked cannabis, supporting its utility. As more HIV-infected individuals initiate ART treatment early and remain on treatment for long periods, reduction of ART-associated morbidity is increasingly important.
Adherence to ART was lower among current marijuana users than non-users in this study, consistent with previous research.35
However, ART adherence was not reduced among the more consistent daily marijuana users. These results are similar to those observed by a previous study of 168 HIV-infected patients on ART in California who reported an increase in ART adherence among daily marijuana users despite decreased adherence among marijuana users overall.36
It appears that for some women, regular marijuana use reduces HIV associated symptoms, and does not impair adherence to ART. Multiple patterns of use are present in the cohort, ranging from highly adherent regular marijuana users, to higher risk women whose marijuana use may be associated with use of other drugs and higher risk sexual behaviors. The association of recent sexual behavior and drug use with recent marijuana use observed in this study has been shown in many other studies,37
as risk behaviors are often correlated. The fact that sex and drug use behavior were not associated with daily
marijuana use in this study underscores the different nature of daily marijuana use and is consistent with the interpretation that some of daily marijuana use is medicinal rather than recreational.
There are several limitations and strengths to the current study. Validity of self-reported drug use has supported in multiple studies,38, 39
although some studies suggest risk behaviors are under-reported compared to use of computer-assisted self interview.22
Whether marijuana use was medicinal or recreational was only specifically asked in 2009 and therefore the trend in medicinal marijuana use could not be evaluated. However, earlier surveys did ask about other questions related to reasons for marijuana use and as the frequency of marijuana use was collected longitudinally the trends in daily marijuana use could be explored. Marijuana abuse/dependence was not assessed. In addition, this was an observation study so marijuana users were self selected (not assigned) and this study did not assess the efficacy or safety of marijuana use. Further, we analyzed changes in marijuana use at cohort level (not the changes within individuals), we can not rule out the possibility that immigrative or emmigrative selection bias might in part explain the changes in marijuana use observed in the cohort.
Our study demonstrates that marijuana use is common among a representative group of U.S. women living with HIV, and that daily marijuana use did not decrease ART adherence. Further, marijuana use was reported by many users to alleviate HIV-related symptoms. Given this pattern, which appears to be part of a broad trend towards use of marijuana in chronic illness, additional research is needed on the optimal formulation, efficacy, effectiveness and safety of this patient led treatment.