Emotional interference and right prefrontal hemodynamic responses in adult cannabis users: a pilot fNIRS study

Cannabis use has been linked to alterations in cognitive control and emotional processing, although findings vary according to use pattern and abstinence status. This pilot study examined whether emotional interference is especially sensitive to short-term abstinence-related differences across cannabis-use profiles and whether such differences are accompanied by distinct prefrontal hemodynamic responses.

Non-users, occasional cannabis users, and chronic cannabis users completed a pre-post cognitive battery including an Emotional Stroop task. In the cannabis-use groups, the post session followed 72 h of abstinence. Behavioral outcomes were analyzed using non-parametric tests. Prefrontal oxygenated and deoxygenated hemoglobin responses were recorded with functional near-infrared spectroscopy (fNIRS) and analyzed using mixed-effects models with false-discovery-rate correction, complemented by Bayesian contrasts on post-pre change scores.

Behavioral effects were concentrated in the Emotional Stroop task. Occasional users showed a significant pre-post reduction in response latency for negative stimuli, together with an accuracy-related pattern in between-group comparisons. Chronic users showed no significant behavioral changes, whereas controls showed a latency change compatible with possible retest effects. fNIRS analyses revealed a significant time × group interaction for deoxygenated hemoglobin in right and bilateral prefrontal regions.

These preliminary findings suggest that emotional interference may be more sensitive than non-emotional cognitive performance to short-term abstinence-related differences across cannabis-use patterns.