Cognitive and subjective effects of mephedrone and factors influencing use of a ‘new legal high’
Article first published online: 18 JAN 2012
© 2012 The Authors, Addiction © 2012 Society for the Study of Addiction
Volume 107, Issue 4, pages 792–800, April 2012
How to Cite
Freeman, T. P., Morgan, C. J. A., Vaughn-Jones, J., Hussain, N., Karimi, K. and Curran, H. V. (2012), Cognitive and subjective effects of mephedrone and factors influencing use of a ‘new legal high’. Addiction, 107: 792–800. doi: 10.1111/j.1360-0443.2011.03719.x
- Issue published online: 28 FEB 2012
- Article first published online: 18 JAN 2012
- Submitted 27 June 2011; initial review completed 16 August 2011; final version accepted 7 November 2011
- legal high;
- psychological wellbeing
Aims Use of the stimulant drug mephedrone increased dramatically in 2009, and it is still available in the United Kingdom after being controlled in April 2010. This study aimed to assess mephedrone's acute cognitive and subjective effects.
Design A mixed within- and between-subjects design compared 20 mephedrone users, first while intoxicated (T1) and secondly drug free (T2); and 20 controls twice when drug free (T1 and T2).
Settings Participants' own homes.
Participants Healthy adults recruited from the community.
Measurements Subjective effects, episodic and working memory, phonological and semantic fluency, psychomotor speed and executive control at were assessed at T1 and T2. Trait schizotypy, depression, changes in mephedrone use since the ban and attitudes influencing use of a hypothetical new legal high were indexed at T2 only.
Findings Compared with controls, mephedrone users had generally impaired prose recall (P = 0.037) and higher scores in schizotypy (P < 0.001) and depression (P = 0.01). Mephedrone acutely primed a marked ‘wanting’ for the drug (P < 0.001), induced stimulant-like effects, impaired working memory (P < 0.001) and enhanced psychomotor speed (P = 0.024). Impulsivity in mephedrone users correlated with the number of hours in an average (nearly 8 hour) mephedrone session (r = 0.6). Users would be drawn to use a new legal high if it were pure, had no long/short term harms, and was positively rated by friends or on the internet.
Conclusions Mephedrone impairs working memory acutely, induces stimulant-like effects in users and is associated with binge use. Factors that influence users' attitudes to new drugs might help to predict future trends in use of the many new psychoactive substances emerging on the internet.