Callous /unemotional traits are associated with clinical severity in referred boys with conduct problems PIA ENEBRINK, HENRIK ANDERSHED, NIKLAS LA ˚ NGSTRO ¨ M Enebrink P, Andershed H, La ˚ngstro ¨m N. Callous  /unemotional traits are associated with clinical severity in referred boys with conduct problems. Nord J Psychiatry 2005;59:431  /440. Oslo. ISSN 0803-9488. Clinical practice with the heterogeneous group of children that present with conduct problems may benefit from improved formats for diagnostic subtyping. We investigatedwhether high levels of callous  /unemotional traits (i.e. lackof empathy, remorselessness and shallow affects) would differentiate clinic-referred conduct-problem boys from those low on such traits. A consecutive series of 41 boys with conduct problems (6  /13 years, mean age  /9.60 years) referred to public child psychiatric units in Sweden were studied with data elicited from caregivers. Conduct-problem boys with many callous  /unemotional traits had significantly more pervasive, varied and aggressive disruptive behavioural problems than boys lowon these traits had. Higher levels of conduct problems in subjects with callous  /unemotional traits were not explained by confounding presence of DSM-IV attention-deficit hyperactivity disorder and oppositional defiant disorder/conduct disorder symptoms. Boys with callous /unemotional traits also experienced poorer household circumstances and lived in families under high stress. Interest- ingly, they less often received help in school from special teachers but were more often diagnosed with dysthymia than boys low on callous  /unemotional traits. We conclude that callous  / unemotional traits might designate a subgroup of boys with different aetiology to their conduct problemsand possibly with specific treatment needs. However, the findings need to be replicated with larger samples.  Callous  /unemotional traits, children, CD, conduct problems, ODD. Pia Enebrink, Division of Forensic Psychiatry, Karolinska Institute, PO Box 4044, SE-141 04 Huddinge, Sweden, E-mail address: pia.enebrink@neurotec.ki.se; Accepted 24 January 2005. C hildhood conduct problems as seen in DSM-IV (1) oppositional defiant disorder (ODD) and conduct disorder (CD) constitute a serious humani- tarian and societal problem because of their high stability over time (e.g. 2, 3) and partial resistance to change using current methods for intervention (4  /6). Previous research clearly indicates that children with conduct problems make up a heterogeneous group in terms of why and how they exhibit their problem behaviour (7). To generate knowledge relevant for developing effective prevention and treatment programmes for children with conduct problems, identifying clinically meaningful subgroups seems important. As children who develop their problem behaviour through different combinations of causal and moderating factors are likely to require varying approaches to treatment (8), researchers and clinicians alike need to consider the possible existence of such subgroups. Previous studies suggest the presence of several distinct pathways to conduct problem behaviour during childhood in terms of primary or most influential causal factors (see 7, for a review). One approach that has gained widespread acceptance is the distinction between children who begin showing conduct problems in child- hood and those whose onset of problem behaviour is in adolescence (1). Importantly, individuals in these two groups not only differ in the timing of onset but also in their adolescent and adult outcomes, with the child- hood-onset group being much more likely to continue to show antisocial and criminal behaviour through adoles- cence and into adulthood (2). However, it is likely that the childhood-onset group is heterogeneous in terms of aetiology (7). There have been some influential attempts to subtype conduct-problem children in the childhood- onset group. These include distinguishing a subgroup with co-morbid attention-deficit hyperactivity disorder (AD/HD) from subjects without this disorder (9, 10). # 2005 Taylor & Francis DOI: 10.1080/08039480500360690