O0024: Licensure Rates and Motor Vehicle Crash Risk Among Young Drivers with Mood Disorders

Background: Diagnoses of mood disorders among adolescents has been increasing in recent years, and its onset often coincides with the time when many teenagers apply for licenses to drive. Neurocognitive skills used for driving, such as executive function and attention, can be impaired by mood disorders. Few studies have assessed licensing outcomes and crash risks among adolescents with mood disorders. The objective of this study is to examine the association between driver licensing rates and crash involvement among adolescents with and without mood disorders.

Methods: We conducted a retrospective cohort study of New Jersey (NJ) residents born from 1987-2000 who were patients of Children’s Hospital of Philadelphia (CHOP) healthcare network and age-eligible to obtain a driver’s license from 2004-2017. Individuals with intellectual disability were excluded. Individuals were categorized/classified as having a mood disorder if they had a CHOP network visit diagnosis or problem list addition of an ICD-9-CM or ICD-10-CM mood disorder code within 2 years of eligibility for an intermediate (restricted) license at age 17.0. Based on these criteria, our study cohort included 86,173 individuals, 1,879 (2.2%) of whom were diagnosed with a mood disorder. Electronic health record data were linked to statewide NJ driver licensing and crash data. We utilized survival analysis to estimate adjusted hazard ratios for licensing and crash outcomes from eligibility until the end of 2017.

Results: The median age at last CHOP visit prior to becoming license eligible was 15 (interquartile range (IQR): 14, 16). Fewer individuals with mood disorders were licensed within their first year of eligibility, compared to those without mood disorders (58% vs. 73%, respectively; p< 0.001). Individuals with mood disorders were 30% less likely to become licensed over the follow-up period, adjusting for sex and race/ethnicity (adjusted hazard ratio: 0.65, 95% CI: 0.62, 0.69) (Figure 1). Among those who obtained their license, drivers with a mood disorder were more likely to be involved in a crash within the first 48 months of licensure than drivers without a mood disorder (41% and 36%, respectively (p=0.001). The overall adjusted hazard ratio for crash risk among drivers with mood disorders was 1.17 (95% CI: 1.07, 1.28) (Figure 2).

Conclusion: Adolescents with mood disorders are less likely to obtain a license to drive. Licensed adolescents with mood disorders were at higher risk of crashing during the study period. Further research is needed to elucidate how mood disorders influence mechanisms affecting licensure and crash rates in this cohort.