Gay men starting to use crystal meth usually increase their sexual risk taking

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A study which followed the same group of gay men over several years has found that individuals who have started to use crystal meth tend to have riskier sexual behaviour than they had in previous years. While this doesn’t definitively demonstrate a causal link, the study also suggests that crystal methamphetamine has a greater impact on sexual behaviour than other drugs.

“Given the ethical impossibility of conducting a randomized, controlled trial of the effects of methamphetamine use on sexual risk behavior, the results presented here provide the strongest evidence yet that initiation of methamphetamine use increases sexual risk behavior among HIV-uninfected MSM,” the researchers write in the Journal of Acquired Immune Deficiency Syndromes.

Crystal meth is a strong stimulant which can increase libido. Users describe having lower inhibitions, greater confidence and feeling sexually compulsive.


risky behaviour

In HIV, refers to any behaviour or action that increases an individual’s probability of acquiring or transmitting HIV, such as having unprotected sex, having multiple partners or sharing drug injection equipment.


Receptive anal intercourse refers to the act of being penetrated during anal intercourse. The receptive partner is the ‘bottom’.

odds ratio (OR)

Comparing one group with another, expresses differences in the odds of something happening. An odds ratio above 1 means something is more likely to happen in the group of interest; an odds ratio below 1 means it is less likely to happen. Similar to ‘relative risk’. 


Another word for sexual drive.

acute infection

The very first few weeks of infection, until the body has created antibodies against the infection. During acute HIV infection, HIV is highly infectious because the virus is multiplying at a very rapid rate. The symptoms of acute HIV infection can include fever, rash, chills, headache, fatigue, nausea, diarrhoea, sore throat, night sweats, appetite loss, mouth ulcers, swollen lymph nodes, muscle and joint aches – all of them symptoms of an acute inflammation (immune reaction).

The data come from a community-based HIV testing programme in San Diego, California. Between 2008 and 2014, a total of 1788 men who have sex with men tested at least twice, with a gap of at least one year between tests. (A further 7117 men tested once only and are not included in this analysis).

The San Diego researchers have recently identified the behavioural characteristics that are associated with acquiring HIV among men using this testing programme. Men can be given a risk score based on the sex they have had in the previous year:

  • Receptive anal sex without a condom with an HIV-positive male partner (3 points)
  • Receptive anal sex without a condom with five or more male partners (3 points)
  • Receptive anal sex without a condom with ten or more male partners (2 points)
  • Diagnosis of a bacterial sexually transmitted infection (2 points)

Men with five or more points were found to be five times more likely than other men to have acute (recent) HIV infection. In the crystal meth study, the researchers therefore used these risk scores in their assessment of risky behaviour.

One-in-ten of the men who tested twice or more (185 men) reported using crystal meth in the previous year. While some men reported crystal meth at each visit, others started or stopped using the drug between HIV tests.

In men who didn’t use crystal meth when they first tested and who then started to use the drug, median risk scores rose from 3 to 5. At the first test individuals’ scores ranged from 0 to 5, whereas when taking crystal meth they ranged from 2 to 7. The difference was statistically significant and was particularly driven by an increase in the number of sexual partners.

In men who stopped using the drug, partner numbers fell significantly but the overall risk score only dropped a little, from 4 to 3.

Men who always used crystal meth maintained the same median score (5), as did men who never used crystal meth (2).

An additional analysis, with data from all 8905 gay men who tested, showed that crystal meth was more strongly associated with sexual risk taking than other drugs. Crystal meth users had three times the odds of a risk score above 5 (odds ratio 3.2) than non-users. The odds were also higher for men using GHB (2.2) amyl nitrites (1.9), cocaine (1.4) and marijuana (1.2). But users of other substances, including ecstasy, ketamine, heroin, Viagra and alcohol weren’t more likely to have a high risk score.

It is common for researchers to demonstrate – as in the last paragraph – that individuals who use certain drugs have more sexual partners or are more likely to have sex without a condom than people who don’t use drugs. But this doesn’t demonstrate that the drugs caused or created the risky behaviour. People with those sexual behaviours may simply be more inclined to use drugs.

The data on repeat testers and crystal meth does give some indication of a sequence of events. In a year in which they didn’t use crystal meth, men had fewer sexual partners and a lower overall risk of HIV infection than in a later year in which they did use the drug. The researchers believe that their data provide evidence of clear links between starting to use crystal meth and increasing sexual risk behaviour.

Nonetheless the data can’t definitively demonstrate a causal link, especially given the lengthy time period in which behaviours were reported (one year). A recent qualitative study of chemsex in the UK identified complex relationships between drug use and risk behaviour, including a minority of men who appeared to use drugs in order to rationalise risk taking. The drugs enabled them to push sexual boundaries and to play out sexual fantasies of danger and transgression.

Interviewees acknowledged that drugs enabled them to do something that they already desired, as this man explained:

“You actually knew what was going to happen. You did it on purpose. You had been saying to yourself all this time that the reason you have sex when you get high is because you only feel horny when you get high. Maybe that’s not true. Maybe you only allow yourself to have sex when you’re high or drunk because being high and being drunk is an excuse to not care anymore. It’s not necessarily that the drugs make you not care, it’s that you’re using them as an excuse so you can go off into this separate little bubble and say that’s not really me.”

The San Diego researchers recommend that gay men who use crystal meth – and men who have high risk scores without drug use – should be offered PrEP and other prevention interventions.


Hoenigl M et al. Clear Links between Starting Methamphetamine and Increasing Sexual Risk Behavior: a cohort study among Men who have Sex with Men. Journal of Acquired Immune Deficiency Syndromes published ahead of print, 2015. (Abstract).

Bourne A et al. The Chemsex study: drug use in sexual settings among gay & bisexual men in Lambeth, Southwark & Lewisham. Sigma Research, 2014. (Full text available online).