RESUMEN
BACKGROUND: Nonsuicidal self-injury (NSSI) behavior is significantly prevalent in both adolescents and psychiatric populations, particularly in individuals with major depressive disorder. NSSI can be considered a result of risky decision making in response to negative emotions, where individuals choose self-harm over other less harmful alternatives, suggesting a potential decision-making deficit in those engaging in NSSI. This study delves into the complex relationship between NSSI and depression severity in decision making and its cognitive underpinnings. METHODS: We assessed decision behaviors in 57 patients with major depressive disorder and NSSI, 42 patients with major depressive disorder without NSSI, and 142 healthy control participants using the Balloon Analog Risk Task, which involves risk taking, learning, and exploration in uncertain scenarios. Using computational modeling, we dissected the nuanced cognitive dimensions influencing decision behaviors. A novel statistical method was developed to elucidate interaction effects between NSSI and depression severity. RESULTS: Contrary to common perceptions, we found that individuals with NSSI behaviors were typically more risk averse. There was also a complex interaction between NSSI and depression severity in shaping risk-taking behaviors. As depressive symptoms intensified, the individuals with NSSI began to perceive less risk and behave more randomly. CONCLUSIONS: This research provides new insights into the cognitive aspects of NSSI and depression, highlighting the importance of considering the influence of comorbid mental disorders when investigating the cognitive underpinnings of such behaviors, especially in the context of prevalent cross-diagnostic phenomena such as NSSI behaviors.