Abstract
The use of drugs is not uncommon among gay, bisexual and other men who have sex with men (MSM). Kissing has been recently identified as a risk factor for gonorrhoea. This study aimed to examine the proportion of MSM who used drugs and how specific drugs influence the likelihood of kissing. We conducted a cross-sectional survey among MSM attending the Melbourne Sexual Health Centre between March 2016 and February 2017. Participants reported their use of eleven specific drugs in the last three months and whether they felt the drug influenced them to kiss someone. Four thousand, three hundred and ninety-one MSM were included in the analysis; 63.1% (n = 2772) used at least one drug in the last three months and 36.6% (n = 1605) used ≥2 drugs. Poppers (44.8%), marijuana (30.8%) and ecstasy (19.1%) were the three most common drugs used among MSM in the last three months. 80.4% of ecstasy users and 74.3% of gammahydroxybutyrate users reported the drug made them much more likely to kiss someone. The majority of MSM reported that the use of heroin (63.6%) and Viagra/Cialis (60.7%) did not influence their kissing behaviour. Drug use is common among sexually active MSM in Melbourne. Most reported the use of ecstasy would increase their likelihood of kissing someone.
Keywords
Introduction
The use of recreational drugs has been increasing among gay, bisexual and other men who have sex with men (MSM) in recent years.1,2 Poppers, marijuana, ecstasy, gammahydroxybutyrate (GHB) and crystal methamphetamine are commonly used among MSM in most western countries such as the UK and the US.3,4 In addition, the proportion of men who use drugs with sex (known as ‘chemsex’) has also increased in the MSM population,1,2 and chemsex is linked to increased sexual health risk taking.5–8 In general, these drugs are used to increase the sexual sensation, arousal, pleasure and feeling of intimacy with their partners.9–11 Most studies have focused on the relationship between drug use and increased sexual risk behaviour. Other qualitative studies have examined the relationship between drug use and increased intimacy, 10 but to date no studies have examined how it influences kissing specifically.
Tongue-kissing has been proposed to be a mode of transmission for oropharyngeal gonorrhoea in MSM.12–14 A Melbourne age-matched case–control study of 531 MSM by Cornelisse et al. 15 found that men who tongue-kissed with casual partners were 2.2 times more likely to have oropharyngeal gonorrhoea compared to men who did not have any tongue-kissing casual partners in the last three months. However, Cornelisse and colleagues were not able to adjust for other sexual practices in their analyses. A more updated Melbourne cross-sectional study of 3677 MSM by Chow et al. 16 identified tongue-kissing as an independent risk factor for oropharyngeal gonorrhoea after adjusting for anal and oral sex. Furthermore, tongue-kissing has also been proposed as a risk factor for oropharyngeal gonorrhoea in heterosexuals from a case report of seven male and female individuals within a sexual network in Melbourne. 17
Understanding how a specific drug influences kissing is important for the design and development of potential public health awareness. The aim of this study was to (1) examine the proportion of MSM reporting recent drug use and (2) explore how a specific drug influences the likelihood of kissing among MSM.
Methods
We conducted a cross-sectional survey among MSM attending the Melbourne Sexual Health Centre (MSHC) between March 2016 and February 2017. The MSHC is a publicly funded sexual health clinic located in the city of Melbourne in Australia, providing approximately 50,000 clinical consultations a year of which nearly 40% are for MSM. 18 All men who self-reported having sex with another man in the last 12 months and attended MSHC during the study period were invited to complete an electronic-based survey via computer-assisted self-interviewing (CASI). A participant information sheet was provided to participants and informed consent was obtained from the participants by clicking ‘yes’ on the consent page prior to the commencement of the survey. Participants did not receive any reimbursement or compensation for participation. This study was approved by the Alfred Hospital Ethics Committee, Melbourne, Australia (project number 69/16).
Participants were provided with a list of 11 different drugs and were asked whether they had used each specific drug anytime in the last three months. The list of 11 drugs was adapted from the Annual Gay Community Periodic Survey, 19 and this included poppers (amyl nitrite), cocaine, crystal meth (crystal methamphetamine or ice), ecstasy (E or 3,4-Methylenedioxymethamphetamine), GHB, heroin, ketamine, marijuana (cannabis), speed (amphetamine), steroids and Viagra/Cialis. For participants who reported the use of any of these drugs, an additional question was asked about how likely the given drug influenced them to kiss or want to kiss someone using a 5-point Likert scale (i.e. much more likely, more likely, no difference, less likely, much less likely). Participants had an option to decline to report the use of any drugs by selecting ‘prefer not to answer’ for both questions.
We excluded participants aged under 16 years and those who did not have any kissing or sexual contacts in the last three months. Participants who preferred not to answer the use of drugs in the last three months were further excluded in the additional question on the likelihood of kissing under the influence of drugs. Only the first response was included if the participant completed the survey multiple times within a three-month period. The proportion of using each drug and the 5-point Likert scale on how drugs influenced kissing were calculated. The exact binomial 95% confidence intervals (CIs) for the proportion were calculated. 20 A chi-squared trend was performed to assess the association between drug use and age. All statistical analyses were performed in Stata (version 14.2, College Station, Texas, USA).
Results
A total of 11,442 MSM were invited to participate in the survey and 4643 MSM (40.6%) completed the survey. Of those, 252 MSM did not meet the inclusion criteria and were excluded, because they were aged under 16 (n = 3), completed the survey more than once within a three-month period (n = 110) and self-reported no kissing or sexual contacts with another man in the last three months (n = 139). The remaining 4391 MSM were included in the final analysis. The median age of MSM was 30 years (IQR: 25–37), 50.7% (n = 2226) were born in Australia and 2.8% (n = 123) were HIV infected. There was a small proportion of MSM who preferred not to answer the use of a specific drug in the last three months; this varied from 37 MSM who preferred not to answer the question on their use of Viagra/Cialis to 48 MSM who preferred not to answer question on their use of marijuana.
There were 2772 (63.1%) MSM who used at least one of the given drugs in the last three months and 1605 (36.6%) MSM who used two or more drugs in the last three months. Figure 1 shows that the top three most common drugs used by MSM in the last three months were poppers (44.8%; 95% CI: 43.4–46.3%), marijuana (30.8%; 95% CI: 29.5–32.2%) and ecstasy (19.1%; 95% CI: 18.0–20.3%). The proportion of MSM using poppers (ptrend = 0.006), crystal meth (ptrend = 0.045) and Viagra/Cialis (ptrend < 0.001) increased with increasing age (Figure 2). In contrast, younger MSM were more likely to use cocaine, ecstasy, ketamine, marijuana and speed compared with older MSM (ptrend < 0.001 for all named drugs). There was no association between age and use of GHB (ptrend = 0.494) or heroin (ptrend = 0.188).

The proportion of drugs used among MSM. GHB: gammahydroxybutyrate.

The proportion of drugs used among MSM, stratified by age groups. GHB: gammahydroxybutyrate.
Figure 3 shows how MSM viewed the influence of each specific drug on their kissing practices. More than half of the MSM felt that the use of heroin (63.6%) and Viagra/Cialis (60.7%) did not influence their likelihood of kissing. However, of the 797 MSM who used ecstasy in the last three months, 80.4% (95% CI: 77.5–83.1%) viewed that the use of ecstasy increased their likelihood of kissing. Similarly, MSM also viewed that the use of GHB (74.3%; 95% CI: 68.9–79.3%) and crystal meth (66.5%; 95% CI: 61.1–71.6%) also increased their likelihood of kissing. Among 270 ketamine users, 30.4% (95% CI: 24.9–36.2%) viewed that the use of ketamine decreased their likelihood of kissing.

Participants’ perceptions of the likelihood of kissing under the influence of a given drug. GHB: gammahydroxybutyrate.
Discussion
This study has shown that almost two-thirds of MSM reported the use of recreational drugs in the last three months and poppers was the most common drug used among MSM. Some drugs such as crystal meth and medication for erectile dysfunction treatment (i.e. Viagra) are more commonly used by older MSM but party drugs such as ecstasy are more commonly used by younger MSM. This is also consistent with the findings from a national survey in the U.S. showing drug use varies across age groups; however, this U.S. survey did not report the age differences across different drugs. 21 Previous reports have found that the use of specific drugs is linked to an increase in intimacy,22,23 but to the best of our knowledge, this is the first study examining kissing related to the use of specific drugs from the participants’ perception. Almost four in five ecstasy users viewed that the use of ecstasy could increase their likelihood of kissing, and this is consistent with a case report of a man kissing more than 15 different men after taking ecstasy on a single night at a gay dance party. 22
This study has some limitations. Firstly, only 40% of MSM attending the clinic completed the survey and this sample may be systematically different from other MSM who did not complete the survey. Secondly, some drugs that are not commonly used (e.g. heroin [n = 11]) in this study population may lead to imprecise estimates on the influence of the drug on their likelihood of kissing. Thirdly, we did not define ‘kissing’ as ‘tongue-kissing’ in our survey and participants might have interpreted ‘kissing’ differently. Fourthly, caution must be taken when interpreting the results on the likelihood of kissing under the influence of a drug as we were unable to distinguish whether the drug influenced the participant to ‘kiss’ or ‘want to kiss’. It is important to note that wanting to kiss someone is not likely to be a risk factor for oropharyngeal gonorrhoea. Fifthly, we were unable to examine the association between the likelihood of kissing and polydrug use.
The 2017 Melbourne Gay Community Periodic Survey reported that 63.9% of community-based MSM had used any recreational drugs in the last six months, 19 which is similar to the finding in the present study. It is important to note that more than one-third of MSM in our study report polydrug use and other studies have found that polydrug use has become more common in recent years among MSM in Australia 19 and the UK. 2 Mixing of drugs can increase individuals’ health risks and harms. 24
Tongue-kissing has been identified as a risk factor for transmitting Neisseria meningitidis 25 and Neisseria gonorrhoeae.15–17 Individuals with N. gonorrhoeae in the oropharynx are almost always asymptomatic, and tongue-kissing a large number of people on a single occasion may lead to the spread of the infection within a sexual network. 17 A clinical trial is underway to investigate whether mouthwash can be used as a novel intervention to prevent against oral transmission of oropharyngeal gonorrhoea.26,27 If mouthwash is found to be effective, this could possibly be translated into a public health campaign for gonorrhoea prevention targeting MSM, particularly MSM who consume drugs that increase the likelihood of kissing.28,29
Recent drug use is commonly reported among MSM in a sexual health clinic setting in Melbourne. Public health interventions which integrate sexual health and substance use are important to reduce harms and advocate safe practices to the community. 30 Furthermore, non-judgmental discussions of sexualised drug use as part of the sexual health consultation are also recommended to provide better and appropriate healthcare service to this population. 31
Footnotes
Acknowledgments
We would like to thank Afrizal Afrizal for his assistance with data extraction and Jun Kit Sze for his assistance in implementing the survey on the CASI system at the MSHC.
Authors’ contribution
EPFC and CKF designed the study. EPFC performed the data analysis and wrote the first draft. All authors were involved in data interpretation. All authors critically revised the manuscript for important intellectual content and approved the final version.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: EPFC was supported by the National Health and Medical Research Council (NHMRC) Early Career Fellowship (1091226) when this study was conducted. This study was funded by the Australian National Health and Medical Research Council Program Grant (568971).
