Substance Use by Canadian Youth - A National Survey of Canadians' Use of Alcohol and Other Drugs - Canadian Addiction Survey (CAS)

Chapter 6: Poly Drug Use

Highlights

• In their lifetime, 37.9% of youth reported using no illicit drug (excluding steroids and inhalants), 38.0% reported using cannabis only, 23.7% reported using some other illicit drug in addition to cannabis and only 0.4% reported using some other illicit drug only.
• Youth do not use cannabis or other illicit drugs in isolation; rather, most youth who currently use cannabis also consume alcohol (98.7%) and most youth who currently use illicit drugs also consume cannabis (91.3%) and alcohol (99.6%).
• When broken down into a user-type variable with four categories that are mutually exclusive, 24.2% of youth are illicit drug users (regardless of cannabis or alcohol use), 37.9% are cannabis users (never illicit drugs, regardless of alcohol use), 29.0% are alcohol users (never illicit or cannabis) and 8.9% are non-users.
• With user-type broken down into all possible combinations of user, 23.7% of youth are lifetime illicit/cannabis/alcohol users, 37.7% are cannabis/ alcohol users, 29.0% are alcohol-only users and 8.9% are non-users.

Introduction

The focus of this chapter is on the combination use of drugs among youth. In examining substance use among youth, it is important to recognize that many users of one illicit drug are often also users of other substances. This chapter will examine the different combinations of substance usage in youth, explore the different combination use/patterns of tobacco smoking, alcohol, cannabis and illicit drugs. It will also examine the demographic characteristics that are associated with use of the various substances and how these characteristics are influenced when taking into account use of other substances.

Regressions will examine the same outcome variables that the previous three chapters have examined. However, in addition to the variables that were controlled for in previous chapters, use of other substances and age of initiation of other substances will also be controlled for so that the impact of use of one substance on another and age of initiation of one substance on the use of another can be examined.

Two derived variables will be examined in this chapter.

User-type8 Variable

A user-type variable was created to examine the different combination patterns of lifetime use that youth engage in when taking into account use of any of 5 illicit drugs (cocaine, heroin, speed, ecstasy, hallucinogens), use of cannabis and use of alcohol.

For the user-type8 variable, the different combination patterns of use are illicit/cannabis/alcohol, illicit/ cannabis, illicit/alcohol, illicit only, cannabis/alcohol, cannabis only, alcohol only and non-user. Categories are exclusive in that all respondents are classified into only one group and membership into each group is determined by having used at least once in lifetime (Figure 6.1).

User-type4 Variable

A second user-type variable was created by modifying user-type8 to more succinctly identify the patterns of usage among youth. For the usertype4 variable, the categories in the usertype8 variable were condensed to examine the proportion of youth who used illicit drugs, cannabis but never other illicit drugs, alcohol but neither cannabis nor illicit drugs, or nothing in their lifetime. Having been classified into the "at least cannabis" group does not mean one has not had experience with alcohol and being classified in the "at least other illicit" does not imply having had no experience with either cannabis or alcohol. As a matter of fact, this classification scheme produces an increasing gradient of exposure to multiple substances. One assumption being made in studying this variable is a "milestone" effect, an assumption of irreversibility. That is, having used at least once, you can never go back to the status of never user (see Figure 6.1). This variable was first examined in a Canadian Addiction Survey: Public Opinions and Attitudes report (Racine, Flight and Sawka, in progress).

Figure 6.1: User-type8 and user-type4 variables

It is important to point out that cannabis is indeed another type of illicit substance; however, it will be examined separately in the present analysis because of its relatively high prevalence of use in the youth population.

In this chapter, to examine combination substance use among youth, the previously discussed two variables will be examined in youth 15 to 24 years of age and, where applicable, compared to the distribution among the total population 15+. In addition, to examine the characteristics of youth who use alcohol, cannabis and at least one of five illicit drugs, multivariate logistic regressions will be conducted with use of other substances as predictors in an attempt to explore the impact of use of different substances on use of others.

Results

Combination Use of Illicit Drugs

Because many users of one illicit drug are often users of another, the configuration of lifetime and past-year use of cannabis and other drugs was examined. Among youth, the most common pattern of lifetime use was cannabis only (38.0%), followed by no illicit drug use (37.9%), other illicit drug and cannabis (23.7%), and use of other illicit drugs only (0.4%) (Table 6.1). When looking at past-year use, no illicit drug use was the most common pattern of use (62.1%), followed by cannabis only (26.7%), other illicit drug and cannabis (10.3%), and other illicit drug only (1.0%).

The pattern of lifetime use for youth was much different from that of adults. No use of illicit drugs was the most common pattern of use among adults (57.5%), followed by cannabis only (27.3%), other illicit drug and cannabis (14.5%), and other illicit drug only (0.7%). Ten percent more youth than adults reported using only cannabis during their lifetime (38.0%), and 20% fewer youth reported having never used any illicit drugs (37.9%). Among lifetime users, however, there was little difference in the user-type patterns between youth and adults: almost equal proportions used cannabis only, other illicit drug and cannabis, and other illicit drug only (Table 6.1).

For past-year use among the total populations, the reported rates of cannabis use only was higher among youth than adults (26.7% versus 8.8%), as was the rate of other illicit drugs in addition to cannabis (10.3% versus 1.2%), whereas the rate of non-users was lower among youth than adults (62.1% versus 89.7%). For past-year use among users, unlike the pattern demonstrated among lifetime users, the reported rates of cannabis-only use was higher among adults than among youth (85.5% versus 70.3%) while other illicit drug use in addition to cannabis was higher among youth than among adults (27.1% versus 11.5%) (Table 6.1).

User-type Patterns (excluding tobacco smoking, inhalants, steroids)

User-type4

Table 6.2 presents a breakdown of the type of users that respondents fall into when considering the user-type4 categories: 24.2% of youth were illicit drug users; 37.9% were cannabis users; 29.0% were alcohol-only users; and 8.9% were non-users. A higher proportion of youth than adults were illicit drug users (24.2% versus 15.2%), cannabis users (37.9% versus 27.1%) and non-users (8.9% versus 6.1%), whereas a lower proportion of youth were alcohol-only users (29.0% versus 51.6%).

Among youth, males were significantly more likely than females to be illicit drug users (27.4% versus 20.8%), whereas females were significantly more likely to be alcohol-only users (32.4% versus 25.6%); there were no differences between males and females in terms of the proportion who were cannabis users or non-users.

More Detailed User-type8 Pattern

Table 6.3 demonstrates that a very small proportion of respondents who fell into the cannabis or illicit drug user-type categories were users of only these substances. Instead, the majority of illicit drug users also consumed cannabis and alcohol, and the majority of cannabis users also consumed alcohol. The most common pattern of use for youth was cannabis and alcohol (37.7%), followed by alcohol only (29.0%), illicit, cannabis and alcohol (23.7%), and non-users of any substance (8.9%). Unlike youth, the most common lifetime pattern of use among adults was alcohol only (51.6%), followed by lower proportions of cannabis and alcohol (26.8%), and illicit drugs, cannabis and alcohol (14.4%).

Combination Substance Use

Table 6.4 presents the combination use of substances. More specifically the table presents how the use of one particular substance may vary depending on use, or non-use, of another substance. From the table, it is apparent that youth who had smoked tobacco in their lifetime were more likely to have used alcohol in their lifetime (96.9%), in contrast with those who never smoked (88.2%). In addition, those who had smoked were also more likely to have used alcohol in the past 12 months than non-smokers (95.4% versus 80.8%). Smokers were also more likely than non-smokers to have used cannabis in their lifetime (87.9% versus 47.3%), cannabis in the past 12 months (65.5% versus 27.3%), and illicit drugs in their life (42.5% versus 9.2%).

Examining alcohol use, those who reported using alcohol in their lifetime were also more likely to report having smoked in their lifetime, used cannabis in their lifetime and in the past 12 months, and to have used illicit drugs in their lifetime or in the past 12 months. It must be pointed out that the estimates for prevalence of use of the various substances among those who reported never using alcohol in their lifetime are suppressed due to cell sizes less than 30. The majority of youth reported having used alcohol in their life, and as such only a small minority overall have never used. As a result of the small number of non-alcohol users to begin with, the number of users of other substances among these non-users was even smaller, resulting in suppression of the estimates. Regarding past 12-month use of alcohol, youth who reported using alcohol in the past 12 months were also more likely than those who did not, to report having smoked in their lifetime, having used cannabis in their lifetime (70.8% versus 16.2%) and in the past 12 months, and illicit drugs in their lifetime and past 12 months.

This trend was also apparent among users and non-users of cannabis. Specifically, cannabis users were more likely than non-users to report smoking in their lifetime (53.4% versus 12.4%), alcohol use in their lifetime (99.6% versus 76.8%) or in the past 12 months (95.5% versus 62.8%), or illicit drug use in their lifetime or in the past 12 months. Those who had used cannabis in the past 12 months were also more likely than those who had not to report smoking (59.7% versus 22.7%), lifetime alcohol use (99.9% versus 85.5%) and past-year use (98.7% versus 73.6%), as well as illicit drug use in their lifetime (49.6% versus 9.1%) and in the past 12 months.

Similarly, youth who had used any of 5 illicit drugs in their lifetime were more likely than those who had not, to report smoking (74.0% versus 28.1%), lifetime alcohol use (99.7% versus 87.9%), past 12-month alcohol use (97.3% versus 78.2%), lifetime cannabis use (98.2% versus 50.0%), and past 12-month cannabis use (76.2% versus 24.6%). Those who currently used illicit drugs were also more likely than those who had not to report smoking (74.6% versus 33.8%), lifetime alcohol use (99.7% versus 89.7%), past-year alcohol use (99.6% versus 80.8%), lifetime cannabis use (99.7% versus 56.6%), and past 12-month cannabis use (91.3% versus 30.1%).

Alcohol Use in Combination with Other Substances

To examine the impact of use of cannabis and other illicit drugs on different measures of alcohol use, the following regressions examine different outcome measures for alcohol both with and without controlling for lifetime cannabis use and lifetime illicit drug use.

Past 12-month use

Without taking other substance use variables into account, youth 18 to 19 years of age were more likely than those 15 to 17 years of age to report having consumed alcohol in the past 12 months, as were youth from the Quebec region in comparison with other regions (Table 6.5). When taking lifetime cannabis and illicit drug use into account, 18- to 19-year-olds were still more likely than 15- to 17-year-olds to report current alcohol use, as were residents from the Quebec region. In addition, the odds of using alcohol in the past 12 months were 8 times higher for youth who had used cannabis in the past 12 months than for those who had not (95.5% versus 62.8%).

Heavy drinking versus light drinking

Without taking use of other substances into account, males were more than twice as likely as females to drink heavily (frequently/infrequently), 18- to 19-year-olds were twice as likely as 15- to 17-year-olds, and youth from the Atlantic region were more likely and those from Quebec less likely to drink heavily (Table 6.6). In addition, youth who started drinking at an earlier age were more likely to drink heavily. When taking use of cannabis or other illicit drugs into account, males and youth from the Atlantic region were still more likely to drink heavily, and those from Quebec were still less likely. When controlling for cannabis and illicit drug use, youth from the Prairie region were also more likely to drink heavily. Interestingly, when the prevalence of use of cannabis and other illicit drugs was equal among those aged 15 to 17, 18 to 19 and 20 to 24, 18- to 19-year-olds were no more likely to drink heavily than 15-to 17-year-olds; however, 20- to 24-year-olds were now less likely than the other two age groups to drink heavily. This suggests that when not controlling for cannabis or illicit drug use, those aged 18 to 19 are more likely than 15- to 17-year-olds to drink heavily because they also use cannabis and illicit drugs at higher rates, and therefore when cannabis and illicit drug use is controlled for, there is no difference between the two groups in terms of heavy drinking. On the other hand, it is noteworthy to point out that even when 18- to 19-and 20- to 24-year-olds consumed cannabis and illicit drugs at the same rate, the older group were less likely to drink heavily. In addition, the odds of drinking heavily were 2 times higher for those who had used cannabis or other illicit drugs in their lifetime than for those who had not used these substances.

Table 6.7 examines the characteristics of youth who reported drinking lightly. When not taking other substance use variables into account, the pattern is the opposite of that for heavy drinking: males were less likely than females, 18- to 19-year-olds were less likely than 15- to 17-year-olds, youth from the Atlantic region were less likely and those from Quebec more likely to drink lightly, and those youth who had started drinking later were significantly more likely to drink lightly. When considering cannabis and other illicit drug use, however, males remained less likely, Atlantic residents less likely and Quebec residents more likely. Age was no longer significantly related to light drinking and there was no difference between 15- to 17- and 18- to 19-year-olds. When controlling for cannabis and illicit drugs, youth from the Prairie region were significantly less likely to drink lightly. Youth who had used cannabis or other illicit drugs in their lifetimes were less likely to drink lightly than those who did not.

Monthly and weekly heavy drinking

When not taking other substance use into account, males were more likely than females, 18- to 19-year-olds were more likely than 15- to 17-year-olds, and residents from the Atlantic region were more likely than those of the other regions to have reported monthly heavy drinking (Table 6.8). In addition, youth who started drinking earlier were more likely to drink heavily monthly. When controlling for cannabis and other illicit drug use, males and Atlantic region residents remained more likely to drink heavily monthly; however, when 15- to 17- and 18- to 19-year-olds consumed cannabis and illicit drugs similarly, there was no difference between the two age groups in prevalence of monthly heavy drinking. In addition, youth from the Quebec region were now significantly less likely to report drinking heavily monthly, and the odds of drinking heavily monthly were 3 times higher among youth who had used cannabis in their lifetime and 1.5 times higher among those who had used illicit drugs in their lifetime in comparison to youth who had not used these substances.

Table 6.9 examines the characteristics of respondents who reported weekly heavy drinking. When not taking other substance use into account, males were more likely than females, 18- to 19-year-olds were more likely than 15- to 17-year-olds, and youth who had started drinking earlier were more likely than those who started later to report drinking heavily at least weekly over the past year. When taking lifetime cannabis or other illicit drug use into account, males were still more likely than females and those who had started drinking earlier were still more likely than those who started later to have reported drinking heavily weekly, but age was no longer related to this pattern of drinking; 18- to 19-year-olds were no longer more likely than 15- to 17-year-olds to drink heavily weekly when they consumed cannabis and illicit drugs at the same rates. In addition, lifetime cannabis use was not related to weekly heavy drinking, youth who used cannabis were no more likely to drink heavily weekly than those who did not, but the odds of drinking heavily were almost double for those who had used 1 of 5 illicit drugs in their lifetime.

Harms due to alcohol use

When not taking any other substance use into account, 18- to 19-year-olds were more likely than 15- to 17-year-olds and those who had started drinking younger were more likely than those who started older to report lifetime harm due to their alcohol use (Table 6.10). Although Quebec youth were less likely and Prairie youth more likely, the main effect of region was not significant. When controlling for lifetime cannabis use and other illicit drug use, however, there was no difference between 15- to 17-year-olds and 18- to 19-year-olds in terms of harms due to drinking. In addition, there was a main effect of region, with Quebec youth less likely and Prairie youth more likely than those from other regions to have experienced harm due to their drinking. Age of alcohol initiation was related to harm; the younger the age of initiation, the more likely the youth were to report harm, as was lifetime cannabis and illicit drug use, with the odds of reporting harm due to alcohol use almost double for users of each.

Cannabis Use in Combination with Other Substances

To examine the impact of use of other substances, namely alcohol and other illicit drugs, on one's use of cannabis, the following regressions examine cannabis use with and without controlling for use of alcohol and lifetime use of illicit drugs. In addition, lifetime cannabis use will be examined among the total population of youth as well as among youth who drank in their lifetime. Regressions are examined among youth who drank in their lifetime for the purpose of examining and controlling for age of alcohol initiation (which is possible only among those who have indeed drunk).

Lifetime use of cannabis among total population of youth

Without taking other substance use variables into account, 18- to 19-year-olds were more likely than 15-to 17-year-olds, and residents from Quebec were more likely, and those from the Atlantic region less likely, than those from other regions to have used cannabis in their lifetime (Table 6.11). When controlling for lifetime alcohol and illicit drug use, there was no difference between 15- to 17- and 18- to 19-year-olds' rates of lifetime cannabis use when both age groups had used alcohol or illicit drugs at similar rates. Youth from the Atlantic region were still less likely and those from Quebec more likely to have used cannabis. In addition, the odds of having used cannabis were more than 5 times higher among youth who drank light infrequently compared to those who were abstainers and former drinkers, 2.5 times higher among light frequent drinkers in comparison with light infrequent drinkers, and 3 times higher among heavy frequent drinkers in comparison with heavy infrequent drinkers. Those who had used illicit drugs in their lifetime were much more likely than those who had not to use cannabis.

Lifetime cannabis use among youth who had drank in their lifetime

Since 90.8% of youth had used alcohol in their lifetime, reported cannabis use was examined among this population of youth (Table 6.12). When not controlling for alcohol pattern or illicit drug use, among those who had drank, 15- to 17-year-olds and youth from the Atlantic region were less likely and those from Quebec were more likely to report using cannabis. When controlling for alcohol age of initiation, pattern of use and illicit drug use, however, youth from Quebec were no longer more likely to use cannabis, whereas those from Ontario were. In addition, the younger that youth started drinking, the more likely they were to report having used cannabis in their lifetime. Also, the odds of having ever used cannabis were 2.6 times higher for light infrequent drinkers than former drinkers, double for light frequent in comparison with light infrequent drinkers, and 2.5 times higher for heavy frequent drinkers when compared with heavy infrequent drinkers. In addition, youth who had used any of 5 illicit drugs in their lifetime were more likely than those who had not reported lifetime cannabis use.

Illicit Drug Use in Combination with Other Substances

To examine the impact of use of other substances, namely alcohol and cannabis on one's use of illicit drugs, the following regressions examine lifetime illicit drug use with and without controlling for use of alcohol and cannabis. In addition, lifetime illicit drug use will be examined among the total population of youth as well as among youth who had drunk in their lifetime, and those who had used cannabis in their lifetime. Regressions are examined among youth who had drunk in their lifetime for the purpose of examining and controlling for age of alcohol initiation (which is only possible among those who have indeed drank). In addition, a regression was also conducted among youth who had drunk and consumed cannabis in their lifetime, so that the impact of age of cannabis initiation on lifetime illicit drug use could be examined.

Lifetime use of illicit drugs among total population of youth

When not taking other substance use variables into account, males were more likely than females, 18- to 19-year-olds were more likely than 15- to 17-year-olds, and residents from the Atlantic region and Ontario region were less likely and those from the Quebec region were more likely to report use of any illicit drug in their lifetime (Table 6.13). When controlling for alcohol status and lifetime cannabis use, however, males are no longer more likely than females to use illicit drugs, but 18- to 19-year-olds are still more likely than 15- to17-year-olds and residents of Atlantic and Ontario regions are still less likely and those from Quebec more likely to have used illicit drugs. In addition, youth from the British Columbia region are also more likely to report lifetime illicit drug use. Alcohol status and cannabis use predicted illicit drug use; those who had drunk heavily/ frequently in the past year were more likely to have used illicit drugs, as were youth who had used cannabis in their lifetime.

Lifetime use of illicit drugs among youth who had drunk in lifetime

In examining the lifetime use of illicit drugs among youth who drank in their lifetime, it is evident that age of alcohol initiation is related to illicit drug use; the younger that youth started drinking, the more likely they were to have used/tried illicit drugs in their lifetime (Table 6.14).

Lifetime use of illicit drugs among youth who had drunk in lifetime and used cannabis in their lifetime

In examining the lifetime use of illicit drugs among youth who had drunk and used cannabis in their lifetime, it is evident that not only does cannabis use predict later illicit drug use, but age of cannabis initiation is also associated with later illicit drug use; the younger that youth started using cannabis, the more likely they were to report lifetime other illicit drug use (Table 6.15).

Summary and Discussion

This chapter examined how users of one illicit drug are usually users of another, as well as how use of one illicit drug can predict use of another. In looking at their use of illicit drugs, most youth use cannabis only (38.0%), followed by those who have never used any illicit drug (37.9%), those who use other illicit drugs in addition to cannabis (23.7%), and other illicit drug-only users (0.4%). This pattern is different from that of adults, in which the most common pattern was those who have never used any illicit drugs (57.5%).

Use of one substance was highly related to use of another substance among youth; tobacco smokers were more likely than non-smokers to report alcohol, cannabis and illicit drug use. This was also demonstrated for alcohol users versus non-users, cannabis users versus non-users, and illicit drug users versus non-users.

The relation of lifetime cannabis and other illicit drug use upon youths' alcohol use was examined. The odds of currently using alcohol were 8.3 times higher among youth who had used cannabis in their lifetime; the odds of drinking heavily were double among youth who had used cannabis or other illicit drugs in their lifetimes; and the odds of drinking heavily monthly and reporting at least one alcohol-related problem during the lifetime were 1.5 to 3 times higher among youth who had used cannabis or other illicit drugs in their lifetime.

The impact of alcohol use pattern and lifetime illicit drug use on whether or not youth used cannabis in their lifetime was examined. When controlling for alcohol use pattern and illicit drug use, 15- to 17-year-olds were no longer less likely to report using cannabis in their lifetime, Quebec youth were still more likely and Atlantic region youth still less likely to report lifetime cannabis use. This indicates that even when these youth consumed alcohol at equal proportions, Quebec youth were still more likely and Atlantic youth still less likely to consume cannabis. Thus, the higher prevalence of cannabis use by Quebec youth and lower prevalence by Atlantic region youth cannot be explained solely by their rates of alcohol use. In addition, as alcohol use pattern increased in severity (from light and infrequent to heavy and frequent) so too did the likelihood of using cannabis in their lifetime. The odds of using cannabis were 34 times higher among those who had used other illicit drugs in their lifetime. The relation of alcohol and illicit drug use on lifetime cannabis use was also examined among drinkers so that the age of alcohol initiation could be controlled for and examined for its impact on cannabis use. When controlling for alcohol pattern and age of initiation, Quebec youth were no longer more likely to report using cannabis. This is interesting in that it suggests that Quebec youth may be more likely to use cannabis because they have a younger age of alcohol initiation; thus, when we control for age of alcohol initiation, they are no longer more likely to use cannabis. More in-depth investigation of this hypothesis is beyond the scope of this report. In relation, even when controlling for alcohol use and age of alcohol initiation, Atlantic youth are still less likely to report cannabis use, suggesting that the reason for their lower prevalence of cannabis use is not solely accounted for by their older age of alcohol initiation. Age of alcohol initiation was, however, inversely related to lifetime cannabis use; the younger that youth started drinking, the more likely they were to use cannabis in their lifetime.

The impact of alcohol and cannabis use on whether or not youth used other illicit drugs was also examined. When controlling for lifetime alcohol and cannabis use, youth from Quebec were still more likely and those from the Atlantic region still significantly less likely to report lifetime illicit drug use. More specifically, differences in illicit drug use between the two regions cannot be accounted for by the higher prevalence of cannabis use among Quebec youth and the lower prevalence among those from the Atlantic region. Even when youth from all regions consumed cannabis and alcohol at the same proportions, Atlantic region youth were still less likely to use illicit drugs, whereas Quebec youth were still more likely. Alcohol use pattern and cannabis use were directly related to lifetime illicit drug use: users of alcohol according to patterns increasing in severity were more likely to use illicit drugs, as were cannabis users versus non-users.

When age of alcohol initiation and drinking pattern was controlled for, Atlantic region youth were no longer less likely to consume illicit drugs. Since solely controlling for prevalence of alcohol use did not impact the lower prevalence of illicit drug use in the Atlantic region, the change in significance when age of alcohol initiation is controlled for suggests that the lower prevalence of illicit drug use in the Atlantic region might be associated with the later age of alcohol initiation in this region (among drinkers). Again, further examination of this hypothesis is beyond the scope of this study. Despite this finding, however, controlling for age of alcohol initiation had no impact on youth from Quebec; they remained more likely to use illicit drugs, suggesting that factors other than a younger age of alcohol initiation might be associated with their higher prevalence of illicit drug use. Age of alcohol initiation was inversely related to illicit drug use among lifetime drinkers. The younger that youth started drinking, the more likely they were to use illicit drugs in their lifetime.

When controlling for age of cannabis initiation, those youth who started using cannabis earlier were more likely to consume illicit drugs in their lifetime. Controlling for age of cannabis initiation did not impact region, but youth from Quebec were still more likely to report illicit drug use in their lifetime. Thus, although age of cannabis initiation has been shown to predict subsequent illicit drug use, the regional differences demonstrated in illicit drug use were not solely accounted for by this factor, suggesting that other factors are also at play in terms of why youth from the Quebec region have a higher prevalence of lifetime illicit drug use.

In summary, use of one substance seems to be a good predictor of use of other substances. In addition, age of alcohol initiation was found to predict use of cannabis and other illicit drugs, and age of cannabis initiation was found to predict use of other illicit drugs. These results emphasize that there are many pathways into the use of so-called "hard" drugs--and introduction to cannabis is but one of them. However, demonstrated here it is apparent that introduction to legal substances, such as alcohol, may also play a role. These findings underscore the importance of targeting age of alcohol and cannabis initiation for preventative purposes; however, results also demonstrate that more factors are at play in terms of predicting youths' use of cannabis and illicit drugs.