Executive functions are impaired in adolescents engaging in non-suicidal self-injury

Background. The aim of this study was to investigate three main aspects of executive functions (EFs), i.e. shifting, updating and inhibition, in adolescents engaging in non-suicidal self-injury (NSSI) as compared with healthy controls. Method. EFs were assessed using the lntra/Extradimensional Set Shift, the Spatial Working Memory (SWM) Test and the Stop Signal Test (SST) from the Cambridge Neuropsychological Test Automated Battery (CANTAB), in a high-severity NSSI group (n=33), a low-severity NSSI group (n=29) and a healthy control group (n=35). Diagnostic characteristics were examined using the Kiddie-Sads-Present and Lifetime Version. Results. There were group differences on the SWM Test. A trend towards an interaction effect of sex revealed that males in the high-severity NSSI group made significantly more errors than males and females in the control group. Both males and females in the high-severity NSSI group made poor use of an efficient strategy in completing the test. The low-severity NSSI group performed poorly on the SST, making more errors than the control group and showing an impaired ability to inhibit initiated responses, as compared with the high-severity NSSI group. There were group differences in frequencies of current and previous major depressive disorder. However, no effects of these diagnoses were found on any of the EF tests. Conclusions. This study demonstrates that NSSI subgroups have distinct deficits in EFs. The high-severity NSSI group has working memory deficits, while the low-severity NSSI group has impaired inhibitory control. This supports the emotion regulation hypothesis.