Nonsuicidal self-injury (NSSI) is defined as direct, intentional physical injury without suicidal intention. Studies revealed that dysfunctional interpersonal relationships and reward-related decision-making may play crucial roles in this maladaptive behavior, especially in adolescents. These interpersonal decision contexts are characterized by constant updating of expectations of rewards and the actual received rewards as well as the associated emotional reactions. These processes have recently been computationally formalized as prediction errors (PE), specifically reward PEs, valence PEs, and arousal PEs (Heffner et al., 2021; Nat Hum Behav). In the current study, the investigators aim to investigate whether these PEs make discernible contributions to social decisions in the context of unfair experiences among adolescents with NSSI and matched healthy control adolescents (HC). Specifically the investigators hypothesized that: 1) reward and emotional PEs show significant predictions of punishment decisions in both groups, 2) however, compared to HC adolescents, the NSSI group will exhibit selective dysfunctions in emotional but not reward PEs leading to punish a norm proposer who provided unfair offers.

Inclusion Criteria:

• 15-18 years
• right-handed
• normal or corrected normal visual acuity
• meet the proposed DSM-5 frequency criteria (e.g., ≥5 days of NSSI behaviors in the past year)

Exclusion Criteria:

• diagnosis of borderline personality disorder, major depressive disorder, other
• psychiatric disorders, etc.
• high suicidal risk
• recent use of medications that can affect neural activity
• have received or are receiving Dialectical Behavior Therapy (DBT) other treatment for emotional problems within the past 6 months
• have a contraindication to MRI scanning (e.g., metal implants, claustrophobia or other conditions that make them inappropriate for MRI scanning)

Treatment-seeking NSSI individuals will be recruited from local hospitals and HC from the community.