Figure 3.

Model of how stressors, in conjunction with initial irregular substance use, may affect progression from experimentation to regular use. Repeated stress can cross-sensitize motivational systems to the motivating effects of substances of abuse, which can be further sensitized by irregular substance use (right side of picture). This might operate in parallel with effects of stress on trait-like factors (left side of figure). People with high trait impulsivity, who are more prone to sensitization, may be at particular risk.