Cannabis and the IQ

The link between cannabis use and cognitive functioning has captivated scientists and the public. In this section, we present our original study followed by a commentary on the study, some letters to the editor, and two subsequent studies. In addition, we provide links to media coverage, most of which is serious and some of which is funny. Collectively, these readings lay out some of the concerns and controversies in this area of research. These readings can be packaged together for teaching purposes.

Original Article


Letters to the Editor

  • Rogeberg O (2013) Correlations between cannabis use and IQ change in the Dunedin cohort are consistent with confounding from socioeconomic status. PNAS, 110:4251-4254.
  • Daly M (2013) Personality may explain the association between cannabis use and neuropsychological impairment. PNAS, 110:E979
  • Moffitt TE, Meier MH, Poulton R, Caspi A. (2013). Reply to Rogeberg and Daly: No evidence that socioeconomic status or personality differences confound the association between cannabis use and IQ decline. PNAS, 110:E980-2

Subsequent, Independent Reports about the Link between Cannabis Use and Neuropsychological Decline

It is instructive to read Meier et al. alongside these articles, and to compare and contrast the approaches and conclusions

Media Coverage

Just google 'cannabis' and 'IQ', and open your mind to the blogosphere. Or compare contrasting positions by visiting

The Potency of Cannabis

2016 NIH Marijuana and Cannabinoid Conference

This conference features many informative presentations. Madeline Meier also speaks about the cannabis-IQ link on Day 1, at 2 hours and 36 minutes.