Brain Development and the Risk for Substance Abuse

Abstract

Drug and alcohol dependence affects millions each year. Adolescence is a period of increased risk for substance use disorders. Understanding how the brain is changing during this developmental window relative to childhood and adulthood and how these changes vary across individuals is critical for predicting risk of later substance abuse and dependence. This chapter provides an overview of recent human imaging and animal studies of brain development focusing on changes in corticostriatal circuitry that has been implicated in addiction. Behavioral, clinical, and neurobiological evidence is provided to help elucidate who may be most at risk for developing a substance abuse problem and whenthey may be most vulnerable.

Adolescent Substance Use and Comorbid Psychopathology: Emotion Regulation Deficits as a Transdiagnostic Risk Factor

“…We focus on how this particular neurological mechanism underlying emotion regulation develops and changes during adolescence in a way that helps explain the increased risk for comorbid psychopathology during this critical developmental window. Specifically, established findings show that adolescents are at a developmental stage in which the limbic-striatal system (responsible for emotional drive, emotional response, arousal, novelty- and sensation-seeking, and reward sensitivity) is more quickly and fully developed than the PFC and related circuitry, which is not fully developed until adulthood (responsible for self-regulation, emotional control, impulse and cognitive control, planning, decision making, and executive functioning) (see [3••, 29••, 34–36, 37••, 38] for reviews). 1 …”

“…The resulting developmentally normative mismatch between increased emotional volatility combined with an underdeveloped regulation system means that for youths particularly at risk (e.g., children of substance-dependent parents [46], those with environmental or genetic risk [29••], or psychosocial stress [38]), difficulty with emotion regulation is an identifiable, transdiagnostic, early embedded risk for psychopathology in adolescence—including disorders of addiction, as well as internalizing and externalizing problems [3••, 11••, 15, 17, 19, 47–49, 50•, 51••, 52, 53••, 54–56]. …”

“…Compared to both children and adults, neurological circuits responsible for emotionally-salient cue responses are more active among adolescents, including an elevated amygdala response to threat [29••, 57] and elevated ventral striatum activity in response to rewards [3••]. Adolescents with a positive family history of SUD (i.e., at least one parent with an SUD) also show greater amygdala activation in response to emotional stimuli [46].…”

“…Substance use escalates significantly through high school where 68 % of 12th graders have tried alcohol, 46 % marijuana, and 25 % any illicit drug other than marijuana [2], with overall rates of substance use peaking between the ages of 16 and 25 [3••]. Approximately 2.8 % of youths aged 12–17 in the USA meet criteria for an AUD and 3.5 % meet criteria for an SUD, with a combined 5.2 % meeting criteria for either an AUD and/or an SUD [4].…”