To further examine the casual relation of these associations, we performed mediation analysis where impulsiveness mediated the relation between GABRA2 and LAPS. Indeed, bootstrap analyses indicated that the effect of GABRA2 on LAPS was partially mediated by impulsiveness. On average 22.6% of the effect of GABRA2 on LAPS is accounted for by the impulsiveness mediating effect. The remaining effect (77.4%) may be mediated by other behavioral risk factors not yet identified, the direct effect of GABRA2 on LAPS and measurement error. It is also possible that GABRA2 affects some factor that influences both impulsiveness and alcohol problem.
