Differentiating Adolescent Self-Injury from Adolescent Depression: Possible Implications for Borderline Personality Development

Self-inflicted injury (SII) in adolescence marks heightened risk for suicide attempts, completed suicide, and adult psychopathology. Although several studies have revealed elevated rates of depression among adolescents who self injure, no one has compared adolescent self injury with adolescent depression on biological, self-, and informant-report markers of vulnerability and risk. Such a comparison may have important implications for treatment, prevention, and developmental models of self injury and borderline personality disorder. We used a multi-method, multi-informant approach to examine how adolescent SII differs from adolescent depression. Self-injuring, depressed, and typical adolescent females (n = 25 per group) and their mothers completed measures of psychopathology and emotion regulation, among others. In addition, we assessed electrodermal responding (EDR), a peripheral biomarker of trait impulsivity. Participants in the SII group (a) scored higher than depressed adolescents on measures of both externalizing psychopathology and emotion dysregulation, and (b) exhibited attenuated EDR, similar to patterns observed among impulsive, externalizing males. Self-injuring adolescents also scored higher on measures of borderline pathology. These findings reveal a coherent pattern of differences between self-injuring and depressed adolescent girls, consistent with theories that SII differs from depression in etiology and developmental course.     

Schizotypy, taxometrics, and disconfirming theories in soft science: Comment on

Among the most consistently replicated findings in literature addressing the latent structure of psychopathology is evidence for a discrete latent class of individuals who are vulnerable to schizophrenia (schizotypes). Rawlings, Williams, Haslam, and Claridge (2008) challenge these findings by subjecting schizotypy scale scores to taxometric analysis, using a data simulation technique to accommodate variable skew. The authors conclude that schizotypy reflects a latent dimension, and that evidence for discrete latent structure from previous studies is likely an artifact of skewed variables. In this comment, we discuss (a) the philosophical implications of disconfirming well replicated findings in soft science with a single study, (b) important considerations when defining the schizotypy construct, (c) intricacies in executing and interpreting a taxometric analysis, and (d) problems with drawing strong conclusions from null results. Considerable evidence suggests that schizotypy is a discrete latent class, a conclusion that is unlikely the result of skewed variables.     

Autonomic correlates of attention-deficit/hyperactivity disorder and oppositional defiant disorder in preschool children

Numerous studies have revealed autonomic underarousal in conduct-disordered adolescents and antisocial adults. It is unknown, however, whether similar autonomic markers are present in at-risk preschoolers. In this study, the authors compared autonomic profiles of 4- to 6-year-old children with attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD; n = 18) with those of age-matched controls (n = 20). Children with ADHD and ODD exhibited fewer electrodermal responses and lengthened cardiac preejection periods at baseline and during reward. Although group differences were not found in baseline respiratory sinus arrhythmia, heart rate changes among ADHD and ODD participants were mediated exclusively by parasympathetic withdrawal, with no independent sympathetic contribution. Heart rate changes among controls were mediated by both autonomic branches. These results suggest that at-risk preschoolers are autonomically similar to older externalizing children.     

A comparison of maximum covariance and K-means cluster analysis in classifying cases into known taxon groups

Maximum covariance (MAXCOV) is a method for determining whether a group of 3 or more indicators marks 1 continuous or 2 discrete latent distributions of individuals. Although the circumstances under which MAXCOV is effective in detecting latent taxa have been specified, its efficiency in classifying cases into groups has not been assessed, and few studies have compared its performance with that of cluster analysis. In the present Monte Carlo study, the classification efficiencies of MAXCOV and the k-means algorithm were compared across ranges of sample size, effect size, indicator number, taxon base rate, and within-groups covariance. When the impact of these parameters was minimized, k-means classified more data points correctly than MAXCOV. However, when the effects of all parameters were increased concurrently, MAXCOV outperformed k-means.     

Comorbid depression and heart rate variability as predictors of aggressive and hyperactive symptom responsiveness during inpatient treatment of conduct‐disordered,ADHD boys

The primary objective of the present study was to assess the utility of (1) comorbid depression and (2) parasympathetic influence on cardiac function as markers for treatment response among aggressive preadolescent males. Inpatient records of 53 patients with conduct disorder and attention deficit hyperactivity disorder (17 with a comorbid depressive disorder) were examined, including an intake electrocardiogram and daily tallies of several indices of aggressive behavior across 3 weeks of stay. The relations of comorbid depression, heart rate variability, and residualized heart rate (primarily of sympathetic origin) to treatment response were assessed through analyses of linear growth functions. Significant vagal tone by diagnostic status interactions were obtained for both frequency and duration indices of aggression, whereby nondepressed patients with high vagal tone deteriorated and depressed patients with high vagal tone improved during hospitalization. No such relation was found for attention deficit hyperactivity disorder symptoms. Patients in the comorbid group also exhibited greater heart rate variability than their nondepressed counterparts. Furthermore, residualized heart rate was predictive of maternal substance use and paternal incarcerations. These findings suggest complex relations among treatment response, comorbid depression, and emotion regulation in male preadolescents with severe behavior disorders. Additionally, the differential prediction afforded by vagal tone and residualized heart rate underscores the importance of assessing both parasympathetic and sympathetic indices of cardiac function as distinct physiological markers. Aggr. Behav. 26:425–441, 2000. © 2000 Wiley‐Liss, Inc.