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 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Systematic review Longitudinal Peer reviewed |
|---|---|
| Topics | Cannabis CBD |
| Keywords | Impulsivity Neuroimaging Disinhibition Effects of cannabis Clinical psychology |
| Citations | 96 |
| Key findings | 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.