Possible age-associated bias in reporting of clinical features of drug dependence: epidemiological evidence on adolescent-onset marijuana use

Authors

  • Chuan-Yu Chen,

    1. Department of Mental Hygiene, Johns Hopkins University, Baltimore, MD, USA
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  • James C. Anthony

    Corresponding author
    1. Department of Mental Hygiene, Johns Hopkins University, Baltimore, MD, USA
      James C. Anthony
      Johns Hopkins University
      Bloomberg School of Public Health
      624 N. Broadway, 8th fl.
      ELCID@Rm.
      893
      Baltimore, MD 21205
      USA
      Tel: + 1 410 955 8551
      Fax: + 1 410 955 9088
      E-mail: janthony@jhu.edu
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James C. Anthony
Johns Hopkins University
Bloomberg School of Public Health
624 N. Broadway, 8th fl.
ELCID@Rm.
893
Baltimore, MD 21205
USA
Tel: + 1 410 955 8551
Fax: + 1 410 955 9088
E-mail: janthony@jhu.edu

ABSTRACT

Aims  To probe recent evidence on apparent excess occurrence of marijuana dependence when marijuana smoking starts in adolescence.

Design and participants  A national sample of recent-onset marijuana users was identified within public data files of the National Household Survey on Drug Abuse (NHSDA), 1995–98 (1866 adolescents and 762 adults).

Measurements  Marijuana dependence was assessed via seven standardized questions about its clinical features, such as being unable to cut down. Multivariate response models (GLM/GEE and MIMIC) were used to evaluate adolescent excess risk and possible item biases.

Findings  Among people who had just started to use marijuana, clinical features of marijuana dependence occurred twice as often among adolescents compared to adults, even with statistical adjustment for other covariates (P < 0.01 from GLM/GEE). MIMIC analyses suggest that adolescent-onset users have somewhat higher levels of marijuana dependence, and they also provide evidence of age-associated response bias for some but not all clinical features of marijuana dependence. That is, even with level of marijuana dependence held constant, adolescent recent-onset users were more likely than adults to report being unable to cut down (P = 0.01) and tolerance (P = 0.029).

Conclusion  Nosologic, methodological and substantive reasons for observed age-related excess in occurrence of marijuana dependence problems among early onset users deserve more attention in future research.

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