Computerised decision making tasks have identified cognitive deficits among people who use illicit drugs. These deficits have been hypothesised as originating in the Ventromedial Prefrontal Cortex (VmPFC) and Orbital Frontal Cortex (OFC). This hypothesis is based on Functional Magnetic Resonance Imaging (fMRI) studies conducted during the decision tasks and comparison studies with patients who have suffered bilateral damage to the VmPFC.
The deficits identified include dysfunctional inhibitory control, hypersensitivity to reward, difficulties in reverse learning (or strategy shifting) and insensitivity to future consequences.
However other research suggests that addicts poor performance is an artefact of tasks which encourage poor decisions initially, paired with an impaired ability to switch task strategies as experience and knowledge is gained.
To date, the dominant trend in this field is to report group data. Using a case-study paradigm, the research reported here indicates a layer of processes that have hitherto not been investigated. This study uses a micro-analysis of individual response behaviours within decision tasks to reveal strategies, correlates and markers of decision making performance.
The sample were 60 males, >1 year heroin addiction, currently receiving stable substitute medication (no opiate use for 2 weeks minimum).
Preliminary results are presented.