Adolescents showing reduced nonsuicidal self-injury often shift toward increased substance use, according to a recent study.

The cohort study, conducted between May 2016 and December 2019, evaluated the development of nonsuicidal self-injury (NSSI) and substance use behaviors in adolescents and young adults, finding that symptom shifting is associated with borderline personality disorder (BPD) pathology. Researchers followed 277 participants (mean age, 14.9 years; 89.9% female) from AtR!Sk, a specialized outpatient clinic providing early intervention for BPD. All participants reported at least 5 NSSI incidents in the year before enrollment. Of the initial cohort, 135 completed the first annual follow-up, and 82 completed the second.

Using growth mixture modeling, researchers identified three latent classes based on trajectories of NSSI and substance use. In Class 1 (11.7% of participants), both NSSI and substance use declined, with a corresponding reduction in BPD symptoms over time. This group showed high initial BPD criteria (mean [SE], 4.64 [0.40]) that decreased significantly by follow-up (2.05 [0.54]). Class 2 (75.9%) demonstrated moderate increases in substance use with declining NSSI, showing relatively lower levels of BPD symptoms (3.18 [0.15] at baseline). Class 3 (12.4%) exhibited significant increases in substance use, particularly notable for polysubstance use involving both alcohol and illicit substances, even as NSSI behaviors declined. This group showed high initial BPD criteria (4.29 [0.41]) that remained elevated or worsened at follow-up (5.15 [0.84]). Older age was associated with higher odds of being in Classes 1 and 3 compared to Class 2.

These findings, published in JAMA Network Open, suggest that a decrease in NSSI behaviors alone may not fully capture clinical progress, as increases in substance use could signal shifts in maladaptive behaviors and related psychopathology. The researchers conclude that monitoring joint trajectories of NSSI and substance use may provide better clinical insight for early detection and targeted treatment of BPD pathology in adolescent psychiatric care.

Full disclosures can be found in the published study.