Consequences of chronic ketamine self-administration upon neurocognitive function and psychological wellbeing: a 1-year longitudinal study
Version of Record online: 17 NOV 2009
© 2009 The Authors. Journal compilation © 2009 Society for the Study of Addiction
Volume 105, Issue 1, pages 121–133, January 2010
How to Cite
Morgan, C. J. A., Muetzelfeldt, L. and Curran, H. V. (2010), Consequences of chronic ketamine self-administration upon neurocognitive function and psychological wellbeing: a 1-year longitudinal study. Addiction, 105: 121–133. doi: 10.1111/j.1360-0443.2009.02761.x
- Issue online: 14 DEC 2009
- Version of Record online: 17 NOV 2009
- Submitted 3 March 2009; initial review completed 27 April 2009; final version accepted 28 July 2009
Vol. 105, Issue 4, 766, Version of Record online: 10 MAR 2010
- Chronic use;
- addiction and substance abuse;
- learning and memory;
- NMDA receptor antagonist;
- recreational use
Background ‘Recreational’ use of ketamine is spreading rapidly among young people. In healthy individuals an acute dose of the N-methyl D-aspartate (NMDA) receptor antagonist ketamine induces marked psychosis-like effects and cognitive impairments, but little is known about the long-term effects of the drug.
Aims To evaluate the long-term neuropsychiatric or cognitive consequences.
Methods A total of 150 individuals were assessed, 30 in each of five groups: frequent ketamine users, infrequent ketamine users, abstinent users, polydrug controls and non-users of illicit drugs. Twelve months later, 80% of these individuals were re-tested.
Results Cognitive deficits were mainly observed only in frequent users. In this group, increasing ketamine use over the year was correlated with decreasing performance on spatial working memory and pattern recognition memory tasks. Assessments of psychological wellbeing showed greater dissociative symptoms in frequent users and a dose–response effect on delusional symptoms, with frequent users scoring higher than infrequent, abstinent users and non-users, respectively. Both frequent and abstinent using groups showed increased depression scores over the 12 months.
Conclusions These findings imply that heavy use of ketamine is harmful to aspects of both cognitive function and psychological wellbeing. Health education campaigns need to raise awareness among young people and clinicians about these negative consequences of ketamine use.