Marijuana Research Today is a free monthly online journal that collates and summarizes the latest research about Marijuana, including details on benefits, cancer, effects, uses, addiction. | ||||||||
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Response perseveration and adaptation in heavy marijuana-smoking adolescents.Lane SD, Cherek DR, Tcheremissine OV, Steinberg JL, Sharon JL Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston, USA. scott.d.lane@uth.tmc.edu The present study examined two behavioral processes - response perseveration and response adaptation - in adolescents who were heavy marijuana smokers and control adolescents. Testing took place in a controlled laboratory setting, using customized software and either a computer keyboard or a custom built response panel for response input. Adolescents age 14-18 were recruited into a heavy smoking (near daily) group (N=22) or a control group (N=31) with <15 lifetime uses of marijuana and no history of substance abuse or dependence. Marijuana use was verified by daily quantification of urinary cannabinoids and self-reports. Participants completed laboratory tasks designed to measure response perseveration (Wisconsin Card Sort Task, WCST) and response adaptation (concurrent variable-ratio reinforcement schedule with changing contingencies). Data were analyzed via ANOVA, controlling for multiple factors including: gender, age, nicotine use, presence of conduct disorder, and subscales of the Youth Self Report. After controlling for these compared to controls marijuana-using participants made significantly more perseverative and total errors on the WCST and showed significantly impaired (e.g., less adaptive) response allocation to the changing reinforcement contingencies on the concurrent-reinforcement task. Within the constraints of the study's limitations in controlling for alternative sources of between-subject variability, the data suggest that individuals who regularly smoke marijuana during adolescence show measurable perturbations in important basic behavioral processes. The data are also consistent with a previous laboratory study demonstrating reduced motivation in marijuana-smoking adolescents versus controls [Lane, S.D., Cherek, D.R., Pietras, C.J., and Steinberg, J.L. (2005). Performance of heavy marijuana-smoking adolescents on a laboratory measure of motivation. Addictive Behaviors, 30, 815-828]. Published 26 February 2007 in Addict Behav, 32(5): 977-90.
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