The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM–) added a specifier for the diagnosis of conduct disorder (CD), labelled ‘ith Limited Prosocial Emotions (LPE) According to theory, CD + LPE and CD Only youth differ in etiological features underlying their conduct problems (ie emotion processing and levels of fearlessness), in severity of antisocial behavior, and in risk of future maladjustment Unfortunately, research on this specifier is hallmarked by notable methodological limitations that hamper a comprehensive test of theory surrounding the specifier and evaluation of its prognostic usefulness This FWO proposal is specifically designed to substantially move research on this specifier forward To do so, criminal justice-involved girls and boys will be extensively tested At baseline, expert-rater diagnostic interviews will be used to ensure an optimal assessment of CD and the LPE specifier During computerized experiments, psychophysiological parameters (heart rate, skin conductance, eye blink startle, facial electromyography) will be recorded to detect blunted/heightened emotional arousal, fearlessness, and facial emotional expressions Facial coding software will also be used as a novel way to analyze video recorded facial expression in reaction to emotional stimuli The prognostic usefulness of the LPE specifier will be tested by collecting information about treatment engagement, substance use, and criminality, 1-2 year after baseline