Format

Send to

Choose Destination
Psychol Med. 2016 Jun;46(8):1663-77. doi: 10.1017/S0033291715003001. Epub 2016 Mar 10.

Continuity of cannabis use and violent offending over the life course.

Author information

1
Institute of Psychiatry,Psychology & Neuroscience,King's College London,London,UK.
2
Division of Psychology and Language Science,University College London,London,UK.
3
Institute of Criminology,University of Cambridge,Cambridge,UK.
4
College of Behavioral and Community Sciences,University of South Florida,Tampa,FL,USA.
5
School of Economics,Political and Policy Sciences,University of Texas at Dallas,Richardson,TX,USA.
6
Forensic Psychiatry Research Unit,Queens Mary University of London,London,UK.

Abstract

BACKGROUND:

Although the association between cannabis use and violence has been reported in the literature, the precise nature of this relationship, especially the directionality of the association, is unclear.

METHOD:

Young males from the Cambridge Study of Delinquent Development (n = 411) were followed up between the ages of 8 and 56 years to prospectively investigate the association between cannabis use and violence. A multi-wave (eight assessments, T1-T8) follow-up design was employed that allowed temporal sequencing of the variables of interest and the analysis of violent outcome measures obtained from two sources: (i) criminal records (violent conviction); and (ii) self-reports. A combination of analytic approaches allowing inferences as to the directionality of associations was employed, including multivariate logistic regression analysis, fixed-effects analysis and cross-lagged modelling.

RESULTS:

Multivariable logistic regression revealed that compared with never-users, continued exposure to cannabis (use at age 18, 32 and 48 years) was associated with a higher risk of subsequent violent behaviour, as indexed by convictions [odds ratio (OR) 7.1, 95% confidence interval (CI) 2.19-23.59] or self-reports (OR 8.9, 95% CI 2.37-46.21). This effect persisted after controlling for other putative risk factors for violence. In predicting violence, fixed-effects analysis and cross-lagged modelling further indicated that this effect could not be explained by other unobserved time-invariant factors. Furthermore, these analyses uncovered a bi-directional relationship between cannabis use and violence.

CONCLUSIONS:

Together, these results provide strong indication that cannabis use predicts subsequent violent offending, suggesting a possible causal effect, and provide empirical evidence that may have implications for public policy.

KEYWORDS:

Cannabis; epidemiology; violence; Δ-9-tetrahydrocannabinol

PMID:
26961342
DOI:
10.1017/S0033291715003001
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Cambridge University Press
Loading ...
Support Center