This lecture reminded me of a study I researched a couple years ago regarding correlations found between impulsivity in children and drug use later in adolescence. The marshmallow test is indicative of self-control. Below is a link from Psych central that explains how a traumatic childhood could initiate impulse control issues which are later ignited into drug abuse. The study focuses on siblings, one with addiction issues and the others without. While correlations were found there was no direct causation links found.