Cannabis users showed heightened brain reward response to money but reduced sensitivity to losses | Research

The takeaway

Chronic cannabis users showed increased ventral striatum activity when anticipating monetary rewards and reduced insula response to losses compared to non-users.

Read this if you want to understand how cannabis use relates to how the brain processes rewards and losses.

Reward brain response correlated with lifetime cannabis joints consumed

What the researchers found

Fourteen chronic cannabis users and 14 non-using controls completed a monetary incentive delay task during fMRI brain scanning. Despite no behavioral performance differences, cannabis users showed significantly greater right ventral striatum (reward center) activation when anticipating rewards.

This heightened reward anticipation response correlated significantly with lifetime cannabis use and total joints consumed. No correlations with abstinence duration were found.

Cannabis users also showed reduced left insula activation in response to loss and loss avoidance outcomes, suggesting diminished sensitivity to negative financial outcomes.

Why it matters

The findings suggested cannabis users may have a heightened sensitivity to rewards generally (not just drug rewards) while being less sensitive to losses, a pattern relevant to understanding risk-taking behavior and continued drug use.

The numbers in context

14 cannabis users vs 14 controls. Reward anticipation: significantly greater right ventral striatum BOLD response in users, correlated with lifetime use. Loss outcomes: reduced left insula cortex activation in users.

How the study worked

Cross-sectional fMRI study comparing 14 chronic cannabis users to 14 drug-naive controls during a monetary incentive delay (MID) task measuring brain activation during reward and loss anticipation and outcome delivery.

What this study cannot tell us

Small sample size (14 per group). Cross-sectional design could not determine whether brain differences preceded or followed cannabis use. Cannabis users may differ from controls in ways beyond drug use.

How to read the evidence

Small cross-sectional fMRI study (14 per group) showing associations but unable to establish causation.

When this study was published

Published in 2010. Neuroimaging research on cannabis and reward processing has expanded considerably since.

The bigger picture

These results supported the opponent process theory of addiction over the reward deficiency syndrome model, suggesting cannabis users had heightened rather than blunted reward processing for non-drug incentives.

Questions still open

Does heightened reward sensitivity predispose people to cannabis use, or does cannabis use create this sensitivity? Would these brain patterns normalize with sustained abstinence?

Common questions

Does cannabis make people more motivated by rewards?

This study found cannabis users had greater brain activation when anticipating rewards, but could not determine whether cannabis caused this or whether reward-sensitive people were more likely to use cannabis.

What does reduced loss sensitivity mean?

Cannabis users showed less brain response to losing money. This pattern could contribute to risky decision-making, as the brain may not register negative outcomes as strongly.

Read the original research

Increased ventral striatal BOLD activity during non-drug reward anticipation in cannabis users.

NeuroImage, 49(1), 1133-43

View on PubMed ↗Publisher’s paper ↗

Citation

Nestor, Liam; Hester, Robert; Garavan, Hugh. (2010). Increased ventral striatal BOLD activity during non-drug reward anticipation in cannabis users.. NeuroImage, 49(1), 1133-43. https://doi.org/10.1016/j.neuroimage.2009.07.022