Pathological Gambling and Motor Impulsivity: A Systematic Review with Meta-Analysis.

Motor impulsivity, which is an impairment in withholding and cancelling inappropriate responses, may account for the inability for pathological gamblers (PGs) to inhibit their urges to gamble. The aim of this systematic review was to perform a quantitative and qualitative synthesis of existing studies in order to assess whether PGs without comorbid substance use disorder have elevated motor impulsivity, relative to healthy controls. An exhaustive literature search led to the identification of 20 studies which met inclusion criteria. A meta-analysis was then conducted on the following measures: stop signal reaction time from the stop signal task; commission errors, omission errors, and Go reaction time from the Go/No-Go task; and the motor impulsiveness subscale of the Barratt Impulsiveness Scale (BIS-Motor). The results revealed a moderate to large mean effect size of stop signal reaction time, small to moderate mean effect sizes for commission errors, omission errors and Go reaction time, and a large mean effect size for the BIS-Motor. Significant heterogeneity in effect sizes was observed on most behavioural measures, but not for the BIS-Motor or omission errors on the Go/No-Go task. Overall, these results suggest that motor impulsivity may be one of the features of PG psychopathology, accounting for their poor inhibitory control over gambling behaviours. Moreover, other deficits in sustained attention, or more generally in executive/cognitive control, may be present in PGs. We discuss the implications, limitations of existing research, and suggested avenues for future studies, particularly the need to acknowledge heterogeneity amongst PGs and amongst different behavioural measures.