Prefrontal dysfunction and impulsive decision-making in female methamphetamine use disorder: a fNIRS study.

Abstract

Background: Heightened preference for immediate over delayed rewards is a well-established feature of substance use disorders, yet the neural basis of this tendency in women with methamphetamine use disorder (MUD) remains insufficiently characterized. Delay discounting provides a useful behavioral index of impulsive decision-making, and convergent evidence implicates prefrontal valuation and control systems in addiction-related choice abnormalities.

Methods: Twenty-five women with MUD and 25 healthy women completed an intertemporal decision-making task under gain and loss frames. Delay discounting rates were estimated using the hyperbolic discounting parameter (k). Functional near-infrared spectroscopy (fNIRS) was used to assess oxygenated hemoglobin (HbO) responses in predefined prefrontal regions of interest, with a focus on the medial orbitofrontal cortex (mOFC) and dorsolateral prefrontal cortex (DLPFC). Trait impulsivity/reinforcement sensitivity was assessed using the BIS/BAS scales. Behavioral discounting was analyzed using a linear mixed model, and neural indices were analyzed using repeated-measures ANCOVAs with age as a covariate and FDR correction across ROIs.

Results: Compared with healthy controls, women with MUD showed significantly steeper delay discounting, indicating a stronger preference for immediate outcomes. They also exhibited lower HbO responses in the right mOFC and left DLPFC during task performance, as well as reduced task-related HbO change in the right DLPFC. Lower right mOFC mean task-window HbO was associated with higher BIS/BAS composite scores. No robust Group × Frame interaction was observed for behavioral discounting.

Conclusions: Women with MUD showed altered intertemporal choice and reduced prefrontal hemodynamic responses in regions implicated in value evaluation and cognitive control. These findings support the relevance of prefrontal dysfunction to impulsive decision-making in female MUD while also indicating that framing-related effects should be interpreted cautiously. The study extends the limited literature on women with MUD and supports the use of fNIRS to examine prefrontal mechanisms of addiction-related decision-making.

Clinical trial number: Not applicable.