Subjective and objective assessments of executive functions are independently predictive of aggressive tendencies in patients with substance use disorder

BACKGROUND AND AIMS

Impairments in executive functions have been found to influence violent behavior. Executive functions are crucial in the treatment of patients with substance use disorders because substance use generally impairs cognitive processes and is therefore detrimental for executive functions thereby reducing control of behavior and thus of consumption impulses. We studied correlations between subjective, i.e. self-report, and objective, i.e. behavior-based, assessment of executive functions and the predictive validity of these measures for aggression in patients with substance use disorder.

METHODS

The study included 64 patients with a diagnosed substance use disorder who were convicted according to the German Criminal Code for crimes they committed in the context of their disorder and were therefore in treatment in forensic psychiatric departments in Germany. Multiple self-report and behavior-based instruments were used to assess executive functions, appetitive and facilitative aggression as well as clinical and sociodemographic variables.

RESULTS

Participants showed impaired executive functions, and measures of executive functions predicted aggressive tendencies and violent offenses. Despite ecological validity of the findings, the subjective and objective assessments of executive functions did not correlate with each other, which corroborates studies in other clinical settings.

CONCLUSIONS

We discuss that this finding may be due to the conceptual differences between subjective and objective measures. Therefore, self-report and behavior-based measures should not be used as proxies of each other but as complementary measures that are useful for comprehensive diagnostics of cognitive impairments and assessment of risks for violent behavior.

Prefrontal oxygenation varies as a function of response inhibition performance in healthy participants but not in youth with non-suicidal self-injury

Non-suicidal self-injury (NSSI), a highly prevalent symptom in adolescence, has been associated with impulsivity. Behavioral measures of response inhibition in combination with the recording of brain activity potentially improve the understanding of the etiology of the behavior. We therefore investigated prefrontal cortex (PFC) oxygenation during a response inhibition task using functional near-infrared spectroscopy (fNIRS) in n = 152 adolescents with NSSI and n = 47 healthy controls. We compared groups regarding behavioral performance and PFC oxygenation and tested whether the association between task performance and PFC oxygenation differed between groups. PFC oxygenation was slightly higher in adolescents with NSSI than in controls. Further, there was evidence for a group by performance interaction: In healthy controls, higher oxygenated hemoglobin was associated with better task performance, which was not the case in the NSSI group. We did not find evidence of associations between PFC oxygenation and clinical measures. Our study provides preliminary evidence of altered brain functional correlates of response inhibition in adolescents with NSSI potentially reflecting deficient top-down regulation of limbic regions through prefrontal regions. Due to methodological limitations of the current study, findings must be interpreted with caution and future studies should optimize task designs for fNIRS processing.

Neurocognitive functioning in adolescents with non-suicidal self-injury

BACKGROUND

Non-suicidal self-injury (NSSI) is a highly prevalent transdiagnostic psychiatric symptom in adolescents. Research in adults has begun to investigate neurocognitive processes associated with NSSI as potential underlying phenotypes. However, research on neurocognitive function in adolescent patients with NSSI is scarce.

METHODS

In this study, we examined neurocognitive functioning in the domains of processing speed, attention, learning, working memory, and executive function in a relatively large sample of n = 240 adolescent patients engaging in NSSI and n = 49 healthy controls. Further, associations between neurocognitive performance and clinical characteristics in the patient group were examined.

RESULTS

While conventional regression analyses showed somewhat weaker neurocognition in the NSSI group in several domains, propensity score matching for IQ showed little evidence that patients engaging in NSSI showed worse neurocognition when general intelligence was considered. Further, a random forest machine learning algorithm was not able to classify NSSI vs. control groups based on neurocognitive features. Within the patient group, linear regression and latent class analyses yielded little evidence that neurocognitive performance was related with clinical characteristics or phenotypes.

LIMITATIONS

As the study did not include a clinical control group, findings might not be specific to NSSI.

CONCLUSIONS

Our findings challenge the importance of specific neurocognitive measures related to the presence or severity of NSSI in adolescents. Future studies should consider general intelligence as an important confounding factor and should focus on domains of affective cognition. Finally, longitudinal studies are needed to determine whether low neurocognitive performance serves to inform prognosis of NSSI or psychopathology in general.