Effects of Cannabis on Impulsivity: A Systematic Review of Neuroimaging Findings
Johannes Wrege, André Schmidt, Anna Walter, Renata Smieskova, Kerstin Bendfeldt, Ernst W. Radue, Undine E. Lang, Stefan Borgwardt
Current Pharmaceutical Design May 10, 2014 DOI: 10.2174/13816128113199990428 via OpenAlex
Summary
AI-generated from the abstractA systematic review of 17 studies (13 meeting inclusion criteria) examined cannabis's effects on impulsivity, disinhibition, and motor control, with a focus on neuroimaging findings from acute and chronic use up to May 2012. Functional imaging studies indicate that chronic cannabis users have lower prefrontal blood flow than controls, while acute administration of THC or marijuana increases brain metabolism in several regions during impulsivity tasks. Structural imaging studies found reduced prefrontal volumes and white matter integrity in cannabis users, which may mediate abnormal impulsivity and mood. The review concludes that more longitudinal studies are needed to determine whether impulsivity precedes cannabis use or cannabis aggravates impulsivity and discontinuation.
Study at a glance
| Characteristics | Systematic review Longitudinal Peer reviewed |
|---|---|
| Topics | Cannabis CBD |
| Keywords | Impulsivity Neuroimaging Disinhibition Effects of cannabis Psychiatry |
| Citations | 96 |
| Key finding | Chronic cannabis users show lower prefrontal blood flow and structural differences in prefrontal volumes and white matter integrity compared to controls, while acute THC or marijuana increases brain metabolism during impulsivity tasks. |
Abstract
We conducted a systematic review to assess the evidence for specific effects of cannabis on impulsivity, disinhibition and motor control. The review had a specific focus on neuroimaging findings associated with acute and chronic use of the drug and covers literature published up until May 2012. Seventeen studies were identified, of which 13 met the inclusion criteria; three studies investigated acute effects of cannabis (1 fMRI, 2 PET), while six studies investigated non-acute functional effects (4 fMRI, 2 PET), and four studies investigated structural alterations. Functional imaging studies of impulsivity studies suggest that prefrontal blood flow is lower in chronic cannabis users than in controls. Studies of acute administration of THC or marijuana report increased brain metabolism in several brain regions during impulsivity tasks. Structural imaging studies of cannabis users found differences in reduced prefrontal volumes and white matter integrity that might mediate the abnormal impulsivity and mood observed in marijuana users. To address the question whether impulsivity as a trait precedes cannabis consumption or whether cannabis aggravates impulsivity and discontinuation of usage more longitudinal study designs are warranted.