Social Behavioral Mechanisms of Drug Comorbidity

Supplement Directors: Bridget Freisthler, Ph.D., Sharon Lipperman-Kreda, Ph.D., and M.J. Paschall


Alcohol is often used in conjunction with other substances such as tobacco, marijuana, and other drugs.  Among adults and young people the co-use of these substances may increase risk for short and long term problem outcomes like fighting, drinking and drunken driving, and child abuse and neglect.  However, since use and problems related to these different substances have been studied in isolation, we know little about how co-occurring use (i.e., use of two or more substances within a few hours) might intensify problems experienced or perpetrated by users.  Our particular interests here are to focus upon the social mechanisms by which co-occurring use of alcohol and marijuana affect problems among underage youth, young adults, and parents of young children.  As we come to understand the determinants of co-occurring substance use in the different contexts for these different groups we will be able to develop more effective environmental preventive interventions for the reduction of comorbid use and problems.

This research supplements research currently being conducted in other components of the “Environmental Approaches to Prevention” Research Center grant:

The Research Goals and Activities of those components have been extended to address these issues and will not be repeated here.  We will instead focus upon the findings which have been forthcoming from this extended work to-date. 

We are extending our examination of youth drinking contexts and associated risks to include situations and risks associated with simultaneous use of alcohol and marijuana (Component #3), we are assessing the contexts in which co-use take place among young adults in order to enhance prevention efforts (Component #2), and we are considering the extent to which parental use of marijuana affects child abuse and neglect (Component #4).


Component #3: The role of contexts in co-occurring substance use and problems among adolescents (15-18 year olds)

We collect real-time data from adolescents in order to precisely identify causal relationships between co-occurring use and problems.  We have found that:

  • The presence of other underage drinkers in every context appears to be associated with greater odds of using alcohol with marijuana.
  • Greater co-occurring use of alcohol and marijuana over an evening increases the odds of violence, drinking and driving, and drunkenness.
  • Greater adult supervision appears to lower odds of simultaneous alcohol and marijuana use by about 55%.

Our qualitative interviews further suggest that adolescents make decisions about substance use and co-use based on physical and social contexts; alcohol was described as best for a party-like atmosphere and marijuana for gatherings of intimate friends in small groups.  Co-occurring use was most often described as taking place sequentially, not necessarily simultaneously, with use occurring in multiple contexts, both static and transitional (e.g. in a car on the way to a restaurant).


Component #2: Co-occurring use of alcohol and other substances and related problems among young adults (18-30 year olds)

We have conducted phone interviews with 2,400 young adults, which included questions about alcohol and other substance use in different contexts.  Analyses of these data reveal that:

  • Young adults who frequent bars and restaurants had approximately 60% lower odds for co-use of alcohol, tobacco or marijuana compared to alcohol use only.
  • Young adults who reported greater percent persons intoxicated at drinking events also reported greater co-use of alcohol, tobacco and/or marijuana.

It appears that drinking in private settings where there are more intoxicated persons presents substantial risks for co-occurring use.  Co-use in these contexts can be addressed through regulatory efforts (e.g., social hosting laws) or other social means (e.g., neighborhood watch).


Component #4: Effects of co-occurring drug use on maladaptive parenting

Marijuana and Alcohol Use, Marijuana Availability, and Child Physical Abuse and Neglect

Alcohol and drug use are often cited as risk factors for child maltreatment; however, very little is known about which specific drugs may be more involved than others.  Our survey data available from parents of children under the age of 13 indicate that:

  • Parents'  use of marijuana is associated with a 3-fold increase in risks for child physical abuse.
  • Risks for physical abuse are doubled among marijuana users who also report any drinking in the past year.

Community-Level Prescription Drug Overdoses, Drug Abuse, Alcohol Outlets and Child Harm

Non-medical prescription opioid use is increasing throughout the U.S.  Sometimes this use leads to prescription opioid overdoses indicating very heavy use, use that may also be related to child maltreatment and unintentional child injury.  Looking at hospital discharge data we found:

  • Increases in community level prescription opioid overdoses over 10 years were related to a 2% increase in child maltreatment and injury discharges.
  • Changes in rates of alcohol and other drug abuse and dependence were also related to greater rates of child maltreatment.

Drug Environments, Drug Use, and Child Physical Abuse

Illicit drug market activities like sales and possession may contribute to physical abuse by intensifying the disruption of social ties, networks and support in neighborhood areas.  Drug availability in these areas may also contribute to greater parental use and related problems.  Integrating survey data with police and hospital discharge data, we have found that: 

  • Parents living in areas with greater rates of drug abuse and dependence are more likely to physically abuse their children. 
  • Self-reported past year drug use is related to more frequent physical abuse.
  • Drug use among parents living in areas with higher rates of drug crimes is related to greater physical abuse of children.
  • Living in a city with higher levels of police-recorded drug incidents is also related to higher rates of physical neglect.