The Relationship of Substance Use to Sexual Activity Among Young Adults in the United States.(Statistical Data Included)

Data on substance use and sexual activity from a nationally representative, probability-based sample of young adults aged 18-30 in 1990 indicate that 86% of respondents had had sex in the previous 12 months, with three-fourths reporting no more than one sexual partner. Seventy-five percent of respondents had consumed alcohol in the past 12 months, 40% had smoked cigarettes and 20% had used marijuana. After adjustment for demographic factors, both sexual activity and a history of multiple partners were positively associated with some measures of substance use. Respondents who drank more frequently, those who were heavy drinkers, those who smoked cigarettes and those who used marijuana in the past year were more likely than others to be sexually active. Those who consumed five or more drinks at a sitting and those who used marijuana were more likely than others to have had more than one sexual partner. Heavy drinkers were also less likely to use condoms; however, the results showed no association between having sex under the influence of alcohol and engaging in unsafe sexual practices.

(Family Planning Perspectives, 27:18-22 & 33, 1995)

Sexual behavior is a key element in the transmission of human immunodeficiency virus (HIV) and AIDS. The use of alcohol or other drugs has been proposed as a contributing factor to sexual risk-taking. Because alcohol and drugs are thought to interfere with judgment and decision-making, it has been suggested that their use in conjunction with sexual activity might increase the probability that risky behavior will occur. (1)

A number of studies have suggested a link between substance use and sexual behavior; people who drink more heavily are more likely to have multiple partners and less likely to use condoms, However, because many of these studies have consisted of convenience samples or have suffered from methodological inconsistencies, they have resulted in contradictory findings. (2) Study populations have been recruited from a variety of sources, including bars and bath houses, (3) advertisements (4) and gay organizations. (5)

Because such samples may not be representative of the general population of homosexuals or heterosexuals, these studies are limited in terms of their generalizability, not only in terms of prevalence estimates of sexual behavior or substance use, but also in assessments of the relationship between the two. For example, samples recruited from bars might contain a larger proportion of people who regularly combine substance use and sex, or who engage in more risky sex in general, thus leading to an inflated estimate of the relationship of substance use to high-risk sex. Indeed, some studies have demonstrated a significant positive association between the frequency of bar-going and level of high-risk sex. (6) Although there have been some analyses of substance use and sexual activity in the general population, (7) only one study (8) has included detailed measures of "safe" and "unsafe" sexual behavior and substance use.

Research on substance use and high-risk sex has also used a variety of measurement strategies. For example, risky sexual behavior has been conceptualized as the frequency of unprotected anal intercourse, (9) the number of sexual partners, (10) the general level of condom use (11) or a summary risk variable constructed from a number of types of behavior. (12) In some studies, alcohol use has not been distinguished from drug use; (13) in others, alcohol and drug use has been defined as the number of substances used (14) or has been measured using detailed quantity-frequency measures. (15)

This article examines the relationship between substance use and sexual behavior--in particular, types of behavior that may result in an increased risk of HIV--in a representative sample of young adults aged 18-30. The focus of this research is on young adults because as a group they report high levels of both sexual activity and alcohol use. This study is part of a project designed to examine the link between drinking and sexual activity in a variety of populations. (16)