Tentative Evidence for Striatal Hyperactivity in Adolescent Cannabis-Using Boys: A Cross-Sectional Multicenter fMRI Study.
Tentative evidence for striatal hyperactivity in adolescent cannabis-using boys: a cross-sectional multicenter fMRI study.
J Psychoactive Drugs. 2013 Apr-Jun; 45(2): 156-67
Jager G, Block RI, Luijten M, Ramsey NF
Adolescents’ risk-taking behavior has been linked to a maturational imbalance between reward (“go”) and inhibitory-control (“stop”)-related brain circuitry. This may drive adolescent drug-taking, such as cannabis use. In this study, we assessed the non-acute effects of adolescent cannabis use on reward-related brain function. We performed a two-site (United States and Netherlands; pooled data) functional magnetic resonance imaging (fMRI) study with a cross-sectional design. Twenty-one abstinent but frequent cannabis-using boys were compared with 24 non-using peers on reward-related brain function, using a monetary incentive delay task with fMRI. Focus was on anticipatory and response stages of reward and brain areas critically involved in reward processing like the striatum. Performance in users was normal. Region-of-interest analysis indicated striatal hyperactivity during anticipatory stages of reward in users. Intriguingly, this effect was most pronounced during non-rewarding events. Striatal hyperactivity in adolescent cannabis users may signify an overly sensitive motivational brain circuitry. Frequent cannabis use during adolescence may induce diminished ability to disengage the motivational circuit when no reward can be obtained. This could strengthen the search for reinforcements like drugs of abuse, even when facing the negative (non-rewarding) consequences. HubMed – drug
Poly-drug and marijuana use among adults who primarily used methamphetamine.
J Psychoactive Drugs. 2013 Apr-Jun; 45(2): 132-40
Herbeck DM, Brecht ML, Lovinger K, Raihan A, Christou D, Sheaff P
This study examines health and legal problems associated with use of commonly reported substances and combinations of substances in a sample of adults with long histories of methamphetamine (meth) use. Data are from a 2009-11 eight-year follow-up interview in an intensive natural history study (N = 373). Respondents who had not used illicit substances in the year preceding the follow-up interview (38%) were compared to users of marijuana-only (16%), meth-only (7%), and poly-drug users who used meth + marijuana but not heroin or cocaine (19%), and poly-drug users who used heroin and/or cocaine (20%). Multinomial regression results indicate that compared to drug-abstinent individuals, greater depressive symptomatology was reported for poly-drug users of meth + marijuana (p = .001), and arrest rates were higher for poly-drug users who used heroin/cocaine (p = .006); no differences in health, mental health, or criminal involvement were observed for meth-only users compared to abstinent individuals. Users of marijuana-only and poly-drug users of heroin/cocaine experienced poorer physical health status than those who were abstinent. To further explore this finding, use of marijuana for medical reasons was examined by drug use group. Overall, health and criminal outcomes varied based on type and combination of substances used, and these differences should be considered when planning treatment strategies. HubMed – drug
Prescription drug misuse and risk behaviors among young injection drug users.
J Psychoactive Drugs. 2013 Apr-Jun; 45(2): 112-21
Johnson KM, Fibbi M, Langer D, Silva K, Lankenau SE
Prescription drug misuse among young adults, especially opioids, is a substantial public health problem in the United States. Although risks associated with injection of illicit drugs are well established, injection and sexual risks associated with misuse of prescription drugs are under-studied. Forty young injection drug users aged 16 to 25 who reported injection of a prescription drug were recruited in 2008-09 in Los Angeles and New York City. Descriptive quantitative and qualitative data were analyzed to illustrate risky injection and sexual behaviors reported in this sample. Over half of participants engaged in risky injection behavior, three-quarters engaged in risky sexual behavior, nearly half reported both risky behaviors, and five did not report either risk behavior while misusing a prescription drug. Prescription opioids, tranquilizers, and stimulants were misused in the context of risky sexual behaviors while only opioids were misused in the context of injection risk behaviors. Access to clean syringes, attitudes and beliefs regarding hepatitis C, and risk reduction through partner selection were identified as key themes that contextualized risk behaviors. Although these findings help identify areas to target educational campaigns, such as prevention of sexually transmitted infections, risk behaviors specifically associated with prescription drug misuse warrant further study. HubMed – drug