Trends in Ecstasy Use in the United States From 1995 to 2001: Comparison With Marijuana Users and Association With Other Drug Use

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1 Experimental and Clinical Psychopharmacology Copyright 2005 by the American Psychological Association 2005, Vol. 13, No. 3, /05/$12.00 DOI: / Trends in Ecstasy Use in the United States From 1995 to 2001: Comparison With Users and Association With Other Drug Use Silvia S. Martins, Guido Mazzotti, and Howard D. Chilcoat Johns Hopkins Bloomberg School of Public Health This study aims to estimate changes in the prevalence of ecstasy use over time, analyze the overlap of ecstasy use and other drug use, and compare other drug use in ecstasy versus marijuana users. The authors hypothesized that ecstasy users early in the epidemic would be polydrug users and that associations between ecstasy and other drug use would diminish as the prevalence of ecstasy use increased. Data were drawn from public use data files from the 1995, 1997, 1999, and 2001 National Household Survey on Drug Abuse. Ecstasy use increased in the U.S. population and the prevalence was greater in younger age groups. Ecstasy users were likely to use a variety of other drugs; however, association of ecstasy use with other drug use was strongest early in the epidemic, diminishing as the number of new users increased. Later, more drug-naive adolescents and young adults began experimenting with ecstasy. These results can orient prevention strategies that target ecstasy users. Ecstasy (3,4-methylenodioxy-methamphetamine; MDMA) is a drug that is often associated with dance music clubs and rave movements, which represent part of the youth culture of the last decade. Although there has been increased interest in the use of this drug in recent years, little is known about the co-occurrence of ecstasy use with other drug use. Few clinical and epidemiologic studies have focused specifically on the issue of ecstasy use in relation to other drug use (Degenhardt, Barker, & Topp, 2004; Gross, Barrett, Shestowsky, & Pihl, 2002; Pedersen & Skrondal, 1999; Topp, Hando, Dillon, & Solowij, 1999). Other drug use among ecstasy users is an issue that is understudied and still needs to be addressed. By examining the co-occurrence of ecstasy and other drug use as ecstasy spreads in the population it is possible to further understanding of the dynamics of the ecstasy epidemic. Ecstasy use became more widespread throughout the world during the 1990s. The drug was introduced to the general population in Western European countries during the late 1980s (Pedersen & Skrondal, 1999) and then spread to North America (Landry, 2002), South America (de Almeida & Silva, 2003), Australia and New Zealand (Topp et al., 1999; Wilkins, Bhatta, Pledger, & Casswell, 2003), South-East Asia (Wilkins et al., 2003), the Near East (Çorapçioglu & Ogel, 2004), and the Middle East (United Silvia S. Martins, Guido Mazzotti, and Howard D. Chilcoat, Department of Mental Health, Johns Hopkins Bloomberg School of Public Health. This research was supported in part by Grant DA11952 from the National Institute on Drug Abuse to Howard D. Chilcoat. Silvia S. Martins received a postdoctoral scholarship from the National Council of Research (CNPq-Brazil). Correspondence concerning this article should be addressed to Silvia S. Martins, Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, 624 North Broadway, 8th Floor, Baltimore, MD smartins@jhsph.edu Nations Office for Drug Control and Drug Prevention, 2001). Epidemiological studies show that ecstasy use is increasing in many countries (von Sydow, Lieb, Pfister, Höfler, & Wittchen, 2002), including the United States (Landry, 2002). For example, in European countries ecstasy use increased during the 1990s and the most recent available data show that lifetime prevalence in the general population was higher than 3% in countries such as Spain, Ireland, the Netherlands, and the United Kingdom (European Monitoring Centre for Drugs and Drug Addiction, 2003). In Australia, 6.1% of the general population aged 14 years or older reported lifetime ecstasy use (Degenhardt et al., 2004). The Monitoring the Future Study has already shown that lifetime ecstasy use has steadily increased in the United States from 1991 to 2001 in college students (from 2.0% to 13.1%) and young adults (from 3.2% to 11.6%), and from 1996 to 2001 in 8th (from 2.3% to 3.5%), 10th (from 4.6% to 6.2%), and 12th (from 4.6% to 9.2%) grade students (Johnston, O Malley, & Bachman, 2001a, 2001b, 2002; Johnston, O Malley, Bachman, & Schulenberg, 2003). According to the same researchers, past year ecstasy use has fallen from 2001 to 2003 in 8th (from 3.5% to 2.1%), 10th (from 6.2% to 3%), and 12th (from 9.2% to 4.5%) grade students and in recent years there was an increase in the proportion of students who see ecstasy as a dangerous drug, but past year prevalence of ecstasy use in these students was still high in 2003 (Johnston et al., 2003). The Drug Abuse Warning Network has reported that there was an increase in emergency room visits associated with ecstasy from 1999 to 2001 (253 visits in 1994 and 5,542 visits in 2001); from 2001 to 2002 (4,026 visits) ecstasy-related emergency visits remained stable (Substance Abuse and Mental Health Services Administration [SAMHSA], 2003). Regardless of the possibility of occurrence of a wide range of harmful effects (Baggott, 2002; Parrott, Sisk, & Turner, 2000), until recently, ecstasy has been viewed as a 244

2 TRENDS IN ECSTASY USE 245 relatively benign substance by its consumers and by the lay population (Topp et al., 1999). Ecstasy users often describe positive effects when they use the drug, saying they feel euphoric, blissful, and more attached to other people (Walters, Foy, & Castro, 2002). Clinical research has demonstrated that ecstasy can cause acute side effects that include: difficulty concentrating, anxiety, depressed mood, dissociation feelings, dry mouth, nausea, insomnia, loss of appetite, and sweating (Baggott, 2002; Liechti, Gamma, & Vollenweider, 2001; Morland, 2000). It is also well established that ecstasy use can cause hyperthermic syndromes, which might lead to death (Baggott, 2002). Long-term ecstasy use might lead to neurotoxic consequences (Montoya, Sorrentino, Lukas, & Price, 2002; Morland, 2000). Most of the studies about ecstasy users conducted in North America have focused on specific subpopulations, such as college students (Boyd et al., 2003) and club and rave attendees (Fendrich, Wislar, Johnson, & Hubbell, 2003; Gross et al., 2002). At first, ecstasy was only used by specific subpopulations, especially those initially associated to rave movements (Pedersen & Skrondal, 2002). During the last decade, rave movements became more popular and ecstasy use has spread into other venues, including at home or at the homes of friends (Degenhardt et al., 2004). The perception of ecstasy as a relatively benign drug might have accelerated the diffusion process of this drug in the population (Ferrence, 2001). Lenton et al. (1997) have hypothesized that, as the rave dance drug culture became more popular, the risk of ecstasy-related harmful effects might increase. After analyzing the drug use habits of 83 rave attendees (76% of them were ecstasy users), these researchers concluded that new ecstasy users have less drug-use experience and have less knowledge about the possible side effects of the drug (Lenton et al., 1997). Assuming Lenton et al. s conclusion is valid for the general population, then, when the prevalence of ecstasy use increases in a country, new ecstasy users should be more drug naive than more experienced ecstasy users and the association between ecstasy and other drug use would decrease over time as the prevalence of ecstasy use increases. Despite the fact that ecstasy use is increasing in North America, little is known about its relationship with other drugs of abuse in the general population. For instance, Gross et al. (2002) described 210 rave attendees in Montreal, Quebec, Canada, and found that first use of ecstasy was mostly preceded by alcohol use, nicotine use, marijuana use, LSD use, psilocybin use, amphetamine use, and cocaine use. Because this was a sample of rave attendees, we cannot generalize these findings to the general population. To our knowledge, no epidemiological study in the United States has addressed co-occurrence of other drug use in ecstasy users. A Norwegian epidemiological study investigated the association of ecstasy use with other drug use. The researchers surveyed 10,812 adolescents living in the city of Oslo (ages 14 17) and concluded that ecstasy use was often intermingled with the use of marijuana, amphetamines, and heroin. According to their study, first ecstasy use occurred after first use of alcohol, cigarettes, marijuana, and amphetamines, whereas it preceded first heroin use (Pedersen & Skrondal, 1999). In an Australian national representative sample of adolescents and young adults, ecstasy was most commonly used with alcohol, marijuana, and amphetamines (Degenhardt et al., 2004). Studies throughout the world have shown that ecstasy use is increasing and that ecstasy use can occur concurrently with other drug use. However, none of these studies have investigated the patterns of other drug use among ecstasy users across a period of time. We hypothesized that adolescents who started to use ecstasy later in the epidemic (i.e., early 2000s) might be more drug naive compared with their counterparts who started using ecstasy early in the epidemic (early 1990s). In order to fill this gap in understanding about the use of ecstasy, we set out to (a) estimate changes in ecstasy prevalence over time, (b) estimate the overlap of ecstasy use and other drug use in the United States, (c) test whether these associations between ecstasy and other drugs change as prevalence of ecstasy use increases in the U.S. population, (d) compare other drug use in ecstasy users versus marijuana users. To analyze the patterns and prevalence of polydrug use among ecstasy users, we found it useful to compare the co-occurrence of other drug use in ecstasy users versus another group of illegal drug users, for example, marijuana users. This approach has advantages over the comparison of ecstasy users with a population that does not use drugs because marijuana users might share more similarities with ecstasy users than nonusers in the general population. Virtually all ecstasy users have used marijuana. is generally considered a gateway drug and its users have made the transition to other drug use. Prevalence of marijuana use in the general population is relatively high, providing a large comparison group and strengthening power. Because power is a function of the sample sizes of both groups that are being compared, having a large comparison group such as marijuana users strengthens the ability to detect differences between groups of drug users. For these reasons, marijuana users are a suitable comparison group for ecstasy users. The comparison of other drug use in ecstasy and marijuana users should help the reader to better understand the extent of other drug involvement among ecstasy users. It is important to stress that we compared ecstasy users with marijuana users who do not use ecstasy, so that ecstasy use among marijuana users would not act as a confounder in the analysis. Method Sample and Measures We analyzed data from the 1995, 1997, 1999, and 2001 National Household Survey on Drug Abuse (NHSDA), which was renamed the National Survey on Drug Use and Health in The NHSDA is sponsored by SAMHSA and is designed to provide estimates of the prevalence of legal and illegal drug use in the household population (aged 12 and over) of the United States. Surveys have been conducted on a regular basis since African American, Hispanic American, and young people were oversampled to increase the precision estimates for these groups. Overall response rates were similar across each year and ranged from 80.6% to 92%

3 246 MARTINS, MAZZOTTI, AND CHILCOAT for household screening (percentage of eligible occupied households among the selected addresses) and 69% to 85.3% for completed interviews. More detailed information about the sampling and survey methodology in the NHSDA can be obtained elsewhere (SAMHSA, 2002). To assess lifetime ecstasy use, a question on the NHSDA questionnaire (part of the hallucinogen section) asks, Have you ever, even once, used Ecstasy, also known as MDMA? To assess lifetime marijuana use, a question asks, Have you ever, even once, used marijuana or hashish? Similar questions are included to assess other drug use. Binge drinking is defined in the NHSDA questionnaire as drinking five or more drinks on the same occasion on at least 1 day in the past 30 days. The following question, related to age of first ecstasy use, was available only on the 2001 NHSDA: Now think only about Ecstasy. How old were you the first time you used Ecstasy, also known as MDMA? Until 2001, the NHSDA questions about ecstasy use only addressed lifetime use of the drug; however, past year and past month indicators of ecstasy use were included in the 2001 NHSDA. In 1999, the surveys underwent a major redesign, changing from a paper-printed questionnaire to a computer-assisted questionnaire. In 1999, a subsample of the interviews was conducted with the paper-printed questionnaire in order to compare both instruments; this comparison showed that lifetime prevalence estimates of drug use tended to be slightly higher with the computer-assisted interview (Chromy, Davis, Packer, & Gfroerer, 2002). Although it is not possible to determine whether increases in prevalence of ecstasy use from 1998 to 1999 were due to an actual increase in prevalence in the population or were the result of changes in survey methods, there are a number of indications suggesting that the increase is real. The increases are consistent with trends observed in the Monitoring the Future Study (in which surveys did not undergo any changes) during 1998 and 1999 (Johnston et al., 2000, 2001a, 2001b, 2002; Johnston et al., 2003). Also, changes in prevalence of ecstasy use from 1998 to 1999 in the NHSDA are consistent with general trends observed through It should be noted that the focus of this article is the associations of ecstasy use with other drug use and demographic characteristics over time. We expect these associations would be less sensitive to changes in survey methodology than would estimates of prevalence (Chilcoat, Lucia, & Breslau, 1999). Statistical Analysis We analyzed demographic data (age, gender, race ethnicity, and total family income) and drug use variables (lifetime ecstasy and other drug use) for all NHSDA surveys cited above. We performed statistical analysis with STATA 8.0 software (Stata- Corporation, 2003) and used its survey commands to account for sample weighting and complex survey design. We analyzed association with demographic characteristics and other drug use associations by using weighted chi-square tests and weighted logistic regression models. Results Demographic Characteristics of Ecstasy Users Lifetime ecstasy use increased from 1995 (1.6%) through 2001 (3.6%) in the overall sample, with prevalence twice as high in 2001 compared with 1995 (odds ratio [OR] 2.2, 95% confidence interval [CI] ). The comparison showed increases from 1995 to 2001 across almost all age categories (ages 12 17: from 1.2% to 3.13%, OR 2.7, CI ; ages 18 25: from 3.45% to 13.09%, OR 4.2, CI ; ages 26 34: from 2.8% to 5.99%, OR 2.2, CI ), with the exception of those older than 35 (Figure 1A). Analyses of ecstasy use by race ethnicity from years 1995 to 2001 showed that prevalence was higher for Whites compared with African Americans (1995: OR 8.1, CI ; 2001: OR 3.3, CI ) and Hispanic Americans (1995: OR 2.3, CI ; 2001: OR 1.4, CI ); however, prevalence of ecstasy use for Whites was not statistically significantly higher than that for Others (includes Native Americans, Native Hawaiians, Pacific Islanders, and Asian Americans). However, ecstasy use has increased in all race ethnicities (Figure 1B). Across all years, ecstasy use was higher for males compared with females; for example, in 1997 males were two times more likely to be ecstasy users than were females (OR 2.1, CI ). However, for females, prevalence of ecstasy use in 2001 was almost three times higher than it was in 1995 (OR 2.6, CI ), whereas it was only twice as high in males in 2001 compared with 1995 (OR 2.0, CI ; Figure 1C). Comparisons of data from 2001 versus those from 1995 show that lifetime ecstasy use significantly increased in almost all family income classes (less than US$20,000: OR 2.9, CI ; US$20,000 US$49,999: OR 2.2, CI ; more than US$75,000: OR 2.1, CI ), with a trend toward increase in those with annual family income of US$50,000 US$74,999 (OR 1.6, CI ; Figure 1D). Other Drug Use Among Ecstasy Users To test the hypothesis that the association of ecstasy use with other drug use would become weaker (especially in the younger age groups) as ecstasy use increased over time, we estimated the prevalence of lifetime other drug use in ecstasy users in 1995, 1997, 1999, and 2001, and compared the prevalence of other drug use among ecstasy users in 2001 versus in 1995 (see Table 1). Our hypothesis was confirmed for several of the drug use associations: The comparison of data from 2001 with those of 1995 showed an overall decrease among ecstasy users in cocaine use (OR 0.6, CI ), LSD use (OR 0.5, CI ), stimulant use (OR 0.7, CI ), and sedative use (from 27.5% in 1995 to 15.0% in 2001, OR 0.5, CI ; not shown in Table 1). There was a trend toward decrease in overall heroin use in ecstasy users that was not statistically significant (OR 0.7, CI ). Overall, prevalence of crack use, inhalant use (50% of ecstasy users in all years; not shown in Table 1), and pain killer use (50% of ecstasy users in all years; not shown in Table 1) remained stable over time, and the overall prevalence of tranquilizer use was 35% in ecstasy users in 1995, 1997, and 2001, with a slight increase in use in 1999 compared with 1995 (46%, OR 1.6, CI ; not shown in Table 1). Adolescent and young adult ecstasy users in 2001 tended to be more drug naive as compared with their 1995 counterparts: There was a steep decrease in heroin use in adolescent ecstasy users, dropping from 38.9% in 1995 to 7.1% in 2001 (OR 0.1, CI ), there

4 TRENDS IN ECSTASY USE 247 Figure 1. Lifetime ecstasy use from 1995 to 2001 by (A) age, (B) race ethnicity, (C) gender, and (D) income. were decreases in crack use in adolescents (OR 0.1, CI ) and young adults (OR 0.5, CI ), there were decreases in LSD use in adolescents (OR 0.1, CI ) and young adults (OR 0.4, CI ), and there was a decrease in sedative use in young adults (from 17.6% in 1995 to 8.6% in 2001, OR 0.4, CI ; not shown in Table 1). Comparisons of data from 2001 versus those from 1995 show that there were trends toward decreases in cocaine use in adolescents (OR 0.5, CI ) and young adults (OR 0.8, CI ), but they were not statistically significant. Contrary to our hypothesis, tranquilizer use (not shown in Table 1) increased in adolescents (from 11.4% in 1995 to 33.2% in 2001; OR 3.8, CI ). Almost all ecstasy users used alcohol (from 98.81% in 1999 to 100% in 1995; not shown in Table 1) and marijuana from 1995 to 2001 (see Table 1). The data from Table 1 enable comparisons of the prevalence of other drug use among ecstasy users within a particular cohort as it ages. For example, the cohort of individuals who were years old in 1995 would have been years old in 2001, which overlaps with the year-old age category in both Table 1 and Figure 1. Within this cohort, lifetime prevalence of ecstasy use increased 10-fold between 1995 and 2001 (from 1.2% for year olds in 1995 to 13.1% for year olds in 2001, as shown in Figure 1). The lifetime prevalence of heroin use among year-old ecstasy users in 1995 was 38.9% but decreased to 9.6% when this cohort was years old in 2001 (see Table 1). It appears that the reduction in heroin use among ecstasy users was due to the addition of ecstasy users since 1995 who were much less likely to be heroin users than at the start of this interval. Similar patterns were observed for crack use among ecstasy users, supporting the hypothesis that ecstasy users in this age group who started using ecstasy after 1995 tended to be more drug naive and used less crack and heroin as compared with those who started to use ecstasy earlier. Other Drug Use in Ecstasy Users Versus Users Given the high degree of co-occurrence of other drug use among ecstasy users, we compared the prevalence of other drug use in ecstasy users with the prevalence of other drug use in marijuana users (who never used ecstasy). Almost all (98%; not shown in Table 1) marijuana users also used alcohol. The prevalence of other lifetime drug use was much higher for ecstasy users versus marijuana users (see Table

5 248 MARTINS, MAZZOTTI, AND CHILCOAT Table 1 Prevalence (in Percentages) of Lifetime Other Drug Use in Ecstasy Users Versus Users Drug and age group Ecstasy (n 298) Prevalence (n 5,583) Ecstasy (n 485) (n 7,298) Ecstasy (n 1,850) (n 16,756) Ecstasy (n 3,169) (n 17,714) Overall Cocaine Overall Crack Overall Heroin Overall LSD Overall Stimulants Overall Note. Percentages are weighted. 1). In contrast to marijuana users, ecstasy users as a whole were more than four times more likely to use cocaine (1995: OR 6.4, 1997: OR 5.4, 1999: OR 5.8, 2001: OR 3.9), were more than three times more likely to use crack (1995: OR 4.2, 1997: OR 5.9, 1999: OR 3.9, 2001: OR 3.2), were seven times more likely to use heroin in 1995 (OR 7.5), and were five times more likely to use heroin in 2001 (OR 5.1). Comparisons of data from 2001 to 1995 showed that there were decreases in prevalence of LSD use and cocaine use in adolescent (LSD: OR 0.4, CI ; cocaine: OR 0.7, CI ) and young adult marijuana users (LSD: OR 0.7, CI ; cocaine: OR 0.6, CI ), which is similar to what occurred in ecstasy users. Although there was a decrease in crack use in adolescent ecstasy users, there was an overall increase in crack use in adolescent marijuana users in 2001 compared with in 1995, mainly due to an increase in crack use among adolescent marijuana users in 1997 (OR 2.4, CI ). Although heroin use decreased in adolescent ecstasy users, it remained stable in marijuana users across all age groups. Sedative use remained stable in marijuana users (prevalence around 6% in all years; not shown in Table 1). Dissimilar to the decrease in stimulant use in ecstasy users, overall stimulant use slightly increased in marijuana users in comparisons of data from 2001 versus 1995 (OR 1.3, CI ) and across all age groups. Comparisons of data from 2001 versus 1995 showed that inhalant use (15.8% vs. 14%, OR 1.2, CI ), tranquilizer use (11.9% vs. 9.6%, OR 1.3, CI ), and pain reliever use (16.9% vs. 12.5%, OR 1.4, CI ) also increased in marijuana users as a whole (results not shown in Table 1). Similar to adolescent ecstasy users, there were trends toward tranquilizer use increase in adolescent marijuana users (6.8% in 2001 vs. 3.85% in 1995, OR 1.9, CI ) as well as in young adult marijuana users (8.9% in 2001 vs. 7.5% in 1995, OR 1.2, CI ), but they were not statistically significant (not shown in Table 1).

6 TRENDS IN ECSTASY USE 249 Binge Drinking Among Ecstasy Users Versus Users Although co-occurrence of many other drugs decreased in ecstasy users, binge drinking increased across ecstasy users of all age ranges from 1995 to 2001 (overall from 45.8% in 1995 to 64.0% in 2001, OR 2.1, CI ; see Figure 2), a pattern similar to that observed among marijuana users (overall from 29.7% to 33.4%, OR 1.2, CI ; see Figure 3). However, considerably more ecstasy users had binge drinking episodes as compared with marijuana users in 1999 and For example, in 1999, 60.3% of the ecstasy users had episodes of binge drinking compared with 35.7% of the marijuana users (OR 2.7, CI ); these numbers in 2001 were 64.0% and 33.4% (OR 3.5, CI ), respectively. Age of First Ecstasy Use and Other Drug Use The addition of age of onset of ecstasy use in the 2001 NHSDA enabled a determination of order of onset of ecstasy relative to other drugs (see Table 2). Most ecstasy users initiated ecstasy use after they had already tried alcohol and marijuana (94.8% and 88.3%, respectively). Fortyfive percent of ecstasy users had initiated LSD before starting to use ecstasy; 17.4% initiated ecstasy and LSD use in the same year and 37.4% initiated ecstasy before LSD use. On the other hand, most ecstasy users had first used ecstasy at a younger age than they first initiated cocaine, crack, heroin, stimulants, inhalants, pain killers (61.3%), tranquilizers (71.1%), and sedatives (87.8%; the last three drug classes not shown in Table 2). Other Drug Use in Past Year and Past Month Ecstasy Use Both past year and past month ecstasy use are only available in the 2001 data file. It is interesting to note that overall other lifetime drug use was similar among past year ecstasy users and lifetime ecstasy users. For instance, 61.8% of lifetime ecstasy users used cocaine and 62.9% of past year ecstasy users used this drug. Analogous results were found when we compared crack use (17.6% of lifetime ecstasy users and 15.3% of past year ecstasy users), heroin Figure 3. Binge drinking in ecstasy users versus marijuana users from 1995 to use (12.2% of lifetime ecstasy users and 10.0% of past year ecstasy users), LSD use (67.0% of lifetime ecstasy users and 60.4% of past year ecstasy users), and stimulant use (38.4% of lifetime ecstasy users and 36.7% of past year ecstasy users). We obtained similar results when we compared lifetime and past year ecstasy users by age group. Overall past month ecstasy users also did not differ from lifetime ecstasy users in other lifetime drug use. However, adolescent (ages 12 17) past month ecstasy users used more cocaine compared with adolescent lifetime ecstasy users (cocaine: 49.02% vs. 33.9%, OR 2.2, CI ). Discussion The main findings of our study can be summarized as follows: (a) ecstasy use increased in the U.S. general population from 1995 to 2001 for all age groups, race ethnicities, genders, and socioeconomic classes; (b) the rate of increase was higher in the younger age groups (especially ages 18 25) as compared with older age groups; (c) ecstasy users were likely to use many other drugs, including alcohol, marijuana, cocaine, crack, heroin, LSD, and stimulants than were marijuana users; (d) association of ecstasy use with other drug use was strongest early in the epidemic and diminished in magnitude as the number of new users increased (e.g., decrease in crack, heroin, and LSD use in adolescent ecstasy users). Because the focus is on demographic and drug use associations with ecstasy use, it is unlikely that the changes implemented in the NHSDA in 1999 would bias the results Figure 2. age. Binge drinking in ecstasy users from 1995 to 2001 by Table 2 Age at Onset of Other Drug Use Compared With Age at Onset of Ecstasy Use (in Percentages) Drug Younger Same age Older Alcohol LSD Cocaine Crack Heroin Inhalants Stimulants Note. From 2001 National Household Survey on Drug Abuse data for lifetime ecstasy users.

7 250 MARTINS, MAZZOTTI, AND CHILCOAT of this study. If an increase in the lifetime use of two drugs, such as ecstasy and cocaine, occurred solely as the result of the changes in the NHSDA in 1999, it does not necessarily mean that this would affect the association of these two drugs. If there was a bias, it would likely be in the direction of increasing the association between these drugs. However, in this study, there was a decrease in reporting the use of cocaine, heroin, and LSD among ecstasy users and a decrease in the associations of these drugs with ecstasy use. Therefore, it is unlikely that changes in the NHSDA would have biased the results of this study. It is noteworthy that the lifetime prevalence of ecstasy use for young adults (ages 18 25) in 2001 was extremely high (13.09%) and was four times higher than it was in Although the prevalence of ecstasy use was highest among Whites and males, researchers and clinicians should keep in mind that its use has increased in other race ethnicities and in females in the past few years. It is interesting to note that ecstasy use among Hispanic Americans was nearly nonexistent during the 1990s but that there was an increase in the prevalence of use for this group in 1999 and Future research will determine whether the increase is maintained for this group. Contrary to the belief that ecstasy use is confined to higher social classes (Beck & Rosenbaum, 1994; Peroutka, Newman, & Harris, 1988), our results showed that ecstasy users belong to all social classes, as defined by annual family income. According to our results, lifetime ecstasy users tend to be polydrug users; however the pattern of other drug use among ecstasy users seems to have changed during the years. Even though the prevalence of binge drinking was already high in this specific group in 1995, this drinking pattern seems to have become even more common among ecstasy users in recent years, suggesting that ecstasy users, particularly those with a more recent onset, might have a higher risk of developing alcohol disorders. It is not possible to determine whether ecstasy and alcohol use occurred on the same occasions by using the NHSDA data because until 2001 data were collected only for lifetime prevalence of ecstasy use. Our results are similar to those of the Degenhardt et al. (2004) epidemiological study conducted in Australia, in which ecstasy users tended to use alcohol, marijuana, and amphetamines in the same time period. These authors also investigated what kind of drugs ecstasy users used concurrently with ecstasy: 74.7% of the young adults and 54.4% of the adolescents had used alcohol together with ecstasy at least once in the year preceding the interview (Degenhardt et al., 2004). Topp et al. (1999) analyzed other drug use in a sample of 329 Australian ecstasy users and stated that polydrug use was the norm among their sample, with at least two thirds of their participants using other drugs (including alcohol) either in combination with ecstasy or on the days following ecstasy use. Clinical studies have already shown that the consumption of both alcohol and ecstasy can increase the risk of development of psychopathological problems such as depression, psychotic disorders, cognitive impairment, bulimia, impulse control disorders, and panic attacks (Schifano, DiFuria, Forza, Minicuci, & Bricolo, 1998). It is interesting to note that in adolescent ecstasy users there was a significant decrease in lifetime heroin, crack, and LSD use from 1995 through A similar pattern of decrease in crack and LSD use was observed in young adult ecstasy users. As we hypothesized, those ecstasy users who began using later in the epidemic appeared to be more drug naive than those who started using ecstasy early in the epidemic. This phenomenon could simply be related to the fact that during the 1990s ecstasy use became more easily accepted by conventional adolescents, and, as such, is not restricted to adolescents who have already tried a variety of other drugs and engage in more deviant behaviors (Baggot, 2002; Parker, Aldridge, & Measham, 1998). On the other hand, the information about adolescents in our sample could be censored. For example, many of these ecstasy users might have recently started using ecstasy and might not have accumulated enough time to initiate use of other drugs, such as cocaine and heroin, subsequent to ecstasy use. According to Lenton et al. (1997), ecstasy users who have less drug-using experience (i.e., who are more drug naive) are prone to a higher risk of drug-related harmful effects because they tend to have less knowledge about the possibility of ecstasy side effects when compared with more experienced users. This should be taken into account when developing prevention and harm reduction strategies for this population. Although our study focuses on trends in ecstasy use from 1995 to 2001, data from the Monitoring the Future Study show that past year ecstasy use decreased among youth from 2001 to 2003 (Johnston et al., 2003). If this decreasing pattern of ecstasy use remains in future population surveys (not only in youth, but also in young adults), it will be necessary to investigate whether the adolescents and young adults who will continue to use ecstasy will be polydrug users, thus resembling those who used ecstasy early in the epidemic. In addition, the factors that determine the maintenance of ecstasy use in a subpopulation of adolescents and young adults while its use decreases need to be addressed in future studies. In the data files analyzed, we only have information on age of first ecstasy use in the 2001 sample and not in previous years. Our results show that ecstasy users have usually tried this drug after having already tried alcohol and marijuana, and, in some cases, first ecstasy use occurred in the same time period as LSD initiation. In a typical drug use sequence, initial ecstasy use usually preceded the use of cocaine, inhalants, pain killers, stimulants, tranquilizers, sedatives, crack, and heroin. These results are consistent with epidemiological and clinical studies conducted in other countries (Gross et al., 2002; Pedersen & Skrondal, 1999). Past year and past month ecstasy use data are available only in the 2001 file. Prevalence of other drug use among these groups of ecstasy users were similar to prevalence of other drug use in lifetime ecstasy users, with the exception of adolescent past month ecstasy users who used more cocaine as compared with adolescent lifetime ecstasy users. Past year and past month indicators of ecstasy use include both chronic and recent onset ecstasy users who need to be further investigated in future studies.

8 TRENDS IN ECSTASY USE 251 Despite the fact that ecstasy is seen as a benign substance (Topp et al., 1999), when we compared other drug use in ecstasy users versus marijuana users who had never tried ecstasy (at least until they were interviewed), there were striking differences: Across all years, the prevalence of all other drug use was much higher among ecstasy users as compared with marijuana users. These results lead us to the following important considerations: (a) ecstasy users in the United States are predominantly polydrug users, which is similar to what was found in epidemiological studies conducted in Europe and Australia (Degenhardt et al., 2004; Pedersen & Skrondal, 1999; Topp et al., 1998); (b) ecstasy use is introduced after alcohol and marijuana and before other drugs in a typical drug use sequence; (c) young ecstasy users tend to be more drug naive and, as such, they are more vulnerable to the harmful interactions of ecstasy with other drugs; (c) public health strategies should address the possibility of harmful interactions between ecstasy and other drug use. Some limitations of our study include the following: (a) Our participants, especially adolescents, might be underreporting their drug use; however, some authors state that underreporting probably remains constant over time (Morral, McCaffrey, & Chien, 2003) and thus should not yield differential patterns of reported co-occurrence over time. If the participants were underreporting their drug use, then the ecstasy and other drug use prevalence would be even higher than the prevalence we obtained; (b) we analyzed ecstasy users as a group, however, there are possible within-group differences that need to be addressed in future studies, and drug use characteristics might be different for chronic and recent onset ecstasy users; (c) data that would help to determine whether ecstasy users are using other drugs on the same occasions they use ecstasy are unavailable; (d) we relied on lifetime prevalence of ecstasy use to conduct our analysis, which is based on participant recall; (e) the methods of administration of the NHSDA were different in the years analyzed, although we suspect that these changes would have little impact on the inference of this study. Prevention and harm reduction strategies that target ecstasy users are still in their infancy. 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