Why Do Some Teens Party Harder?

Behavioral inhibition can be detected in babies as young as four months

(RxWiki News) Some kids are shy and others are super outgoing. Babies with behavioral inhibition tend to have riskier behavior as teens and can often include substance use.

A recent study followed 83 kids from 4 months of age into young adulthood. Results found that kids with behavioral inhibition as babies, developed into young adults with higher rates of substance use.

"Talk to your kids about responsible behavior."

Ayelet Lahat, PhD, and Nathan Fox, PhD, from the Department of Human Development at the University of Maryland, led an investigation into childhood predictors of later substance abuse.

Originally, the study began with 443 infants tested at 4 months for behavioral inhibition. This was done by comparing reactions to various stimuli and rated by temperament scales.

Re-testing was done at 14 months, 24 months, 4 years and 7 years of age, by this time the sample group of participants had dwindled to 117.

In later adolescence, the behavioral inhibition tests changed to suit the more mature and mentally capable teenagers to a monetary incentive delay task (MID).

The MID task was designed to give a greater monetary reward to those who could wait longer.

This task was performed while the teens were being given a functional magnetic resonance imaging (fMRI) brain scan that could see how the brain was reacting to the task.

Once the group turned 16 years of age, only 83 participants remained. Each of which was surveyed about drinking, substance use and risky behavior.

Risky behavior included unsafe driving, tobacco use, risky sexual behavior and aggressive behavior.

A total of 88 percent reported that they had used alcohol and 53 percent reported drug use.

Researchers found that individuals with early childhood behavioral inhibition and high brain activity during the monetary incentive task also reported higher levels of substance use as young adults.

These results were consistent with other studies testing for the same links between behavioral inhibition, brain activation and risky behavior later in life.

These findings could help mental health professionals design treatment methods for these kinds of adolescents to help them seek fulfillment in safer environments and focus energy into positive tasks.

This study was published in September in Translational Psychiatry.

Funding for this study was provided by the National Institute of Health and the National Institute of Mental Health. No conflicts of interest were found.

Review Date: 
October 4, 2012