Behavioral inhibition and task-related cortical hemodynamic responses in adolescents with depression and non-suicidal self-injury: a functional near-infrared spectroscopy study

Non-suicidal self-injury (NSSI) is increasingly prevalent among adolescents, particularly those with depression. Impulsivity is a significant risk factor for NSSI, but its neural mechanisms are not fully understood. Functional near-infrared spectroscopy (fNIRS) offers a non-invasive optical approach for investigating impulsivity in adolescents. This study aimed to examine behavioral performance and task-related cortical activation during impulsivity tasks in adolescents with depression and NSSI. A total of 89 adolescents aged 12–18 years participated in the study, including a group with depression and NSSI ( n = 33), a depression-only group ( n = 26), and a healthy control group ( n = 30). Participants completed a Two-choice Oddball task and a Flanker task to assess behavioral and cognitive inhibition, respectively. During the tasks, changes in oxyhemoglobin concentration in the prefrontal cortex were recorded using fNIRS. One-way analysis of variance (ANOVA) was conducted to compare behavioral and channel-wise task-related HbO β values across the three groups, with Benjamini–Hochberg FDR correction applied across the 44 valid fNIRS channels for channel-wise analyses. In the Flanker task, no significant group differences were observed in accuracy or reaction time. In the Two-choice Oddball task, the Depression with NSSI group showed lower accuracy than healthy controls, suggesting poorer behavioral inhibition. In the fNIRS analyses, several nominal channel-wise differences in HbO β values were observed during the Two-choice Oddball task in prefrontal and adjacent regions. However, none of these channel-wise group differences survived FDR correction across the 44 valid channels; therefore, the fNIRS findings should be interpreted as exploratory. Adolescents with depression and NSSI showed poorer behavioral inhibition than healthy controls under the Two-choice Oddball task condition. The fNIRS findings did not survive correction for multiple comparisons and therefore should not be interpreted as confirmatory neural markers of depression with NSSI. Larger and better-controlled studies are needed to clarify whether and how task-related cortical activation is associated with NSSI in adolescents with depression.