A Within-Person Analysis of the Association between Borderline Personality Disorder and Alcohol Use in Adolescents.

Many studies examining the association between borderline personality disorder (BPD) and alcohol use during adolescence have focused on between-individual differences (rank order stability), comparing whether adolescents with elevated rates of alcohol use have higher BPD symptoms than those with lower rates of alcohol use. As such, the extent to which an individual's alcohol use is associated with concurrent and future BPD symptoms has been relatively unstudied. The current study assessed year-to-year fluctuations in alcohol use and BPD symptoms in a large urban sample of girls from age 14 to age 17 (N = 2450). The primary aim was to examine whether increases in alcohol use were associated with increases in adolescent girls' BPD symptoms in the same year and in the following year. Results of fixed-effects (within-individual) models revealed that even while controlling for the time-varying impact of symptoms of both internalizing and externalizing disorders, prior and concurrent other substance use, and all time invariant, pre-existing differences between individuals, higher past-year alcohol use was associated with higher levels of BPD symptoms. Furthermore, this association did not vary by age, or by sociodemographic factors, including child race and socioeconomic status of the family. The results of this study indicate heightened risk for the exacerbation of BPD symptoms following increases in alcohol use frequency and highlight the potential utility of interventions targeting drinking behavior for preventing escalations in BPD symptoms.