Tendencies toward impulsivity in early adolescence are linked with a variety of poor outcomes in later adolescence, including antisocial personality disorder and alcohol use disorder. However, by the time teenagers reach mid-adolescence, it may be too late to target impulsivity to prevent the development of these behavioral disorders.

Past research has shown the link between impulsivity and these disorders, but not how it unfolds. Now, a new study based on data tracking hundreds of Philadelphia youth over more than a half-dozen years details the complex pathway connecting impulsivity, alcohol use, and antisocial behavior.

The findings suggest that targeting adolescents who exhibit high levels of impulsivity in early adolescence could halt a cascading chain of events that leads to late-adolescence antisocial personality disorder (APD) and alcohol use disorder (AUD).

"Kids with impulse control problems are at risk for a variety of adverse outcomes, such as drug use, acting-out behaviour, and antisocial behaviour," said study co-author Dan Romer, research director of the Annenberg Public Policy Center of the University of Pennsylvania. 

"What we've found is that you've got to start mitigating impulsivity before it starts influencing behaviours that lead to substance use and antisocial behaviour disorders. Once adolescents are on a trajectory of engaging in those behaviours, it may become more difficult to prevent disorders later in adolescence than it is to treat impulsivity itself."

The open-access study, published this week in the Journal of Adolescent Health, was conducted by researchers from the Annenberg Public Policy Center (APPC), University of Amsterdam, University of Oregon, and Children's Hospital of Philadelphia.

The Philadelphia Trajectory Study

The study is based on data from the Philadelphia Trajectory Study, a six-wave study during which participants ages 10 to 12 were interviewed annually from 2004 to 2010, with a final two-year follow-up in 2012. The current study relies on five years of self-reported data, from waves 3 through 6. During the final wave, the participants were 18 to 21 years old. The study was based on data from 364 adolescents (at wave 3) of diverse ethnic backgrounds.

The researchers said that to the best of their knowledge, "This is the first study to investigate cascading mediating links between impulsivity, alcohol use, and antisocial behaviour across adolescence."

Adolescent impulsivity and antisocial behaviour

The researchers found that from early to mid-adolescence, changes in impulsivity predicted changes in antisocial behaviour and alcohol use. But by the time the participants had reached mid-to-late adolescence, changes in impulsivity no longer predicted those behaviours. Instead, it was engaging in antisocial behaviour that predicted subsequent symptoms of both alcohol use and antisocial personality disorders.

"It is also important to target antisocial behaviour to interrupt the cascade that predicts both alcohol use disorder and antisocial personality disorder," said the lead author, Ivy Defoe, an assistant professor at the University of Amsterdam and a former postdoctoral fellow at the Annenberg Public Policy Center. "In fact, the study showed that increases in antisocial behaviour in mid-to late adolescence further predicted increases in impulsivity as well. This is consistent with labelling theory that suggests that individuals who show antisocial behaviour are subsequently labelled as 'antisocial' or 'rule-breakers,' which causes them to further exhibit attributes that are associated with such behaviour."

In view of the mental health crisis among adolescents, it is critical to identify youths with conditions that can lead to later disorders. Screening for such conditions is one way to alert parents about the risks and to refer youths for treatment. As the researchers said, "Intervening early is critical to further avoid the consequences of impulsivity which are more difficult to reverse once psychopathology has developed." Such interventions, the researchers said, could include mindfulness training and family-based interventions in which parents and caregivers work to help their child overcome harmful impulsive tendencies.

Most of the participants were from families with a low-middle socioeconomic status (SES). The researchers found that socioeconomic status was a significant predictor of impulsivity at each wave of the study. "Future research could further investigate the mechanisms by which early exposure to socioeconomic disadvantage influences heightened impulsivity during adolescence, including impacts on child executive functioning and parenting behaviours," the researchers said.

In addition to Defoe and Romer, the study was authored by Atika Khurana of the University of Oregon and Laura M. Betancourt and Hallam Hurt of Children's Hospital of Philadelphia.

--Annenberg Public Policy Center of the University of Pennsylvania