Dimensional profiling of psychopathology in children and adolescents based on the K-SADS-PL and an analysis of the construct validity of two ADHD symptom dimensions

Abstract

Objectives

The traditional view on psychiatric disorders as categorical and distinct is being challenged by perspectives emphasizing the relevance of dimensional and transdiagnostic assessment. However, most diagnostic instruments are based on a categorical view with a threshold-approach to disease classification.

Methods

We here describe algorithms for dimensionalizing the psychopathological ratings of the widely used diagnostic interview for children and adolescents, the Kiddie-Schedule for Affective Disorders and Schizophrenia – Present and Lifetime Version (K-SADS-PL). We further evaluate the criterion-related construct validity of the dimensionalized attention-deficit/hyperactivity disorder (ADHD) scales using Rasch models in a sample of 590 children (mean age 10.29 (.36), 49% girls).

Results

The algorithms generate scores of current symptom load, i.e., the sum of clinician-rated symptoms within each disorder assessed with the interview. We found support for counting symptoms of inattention and hyperactivity/impulsivity, respectively, but not for a single combined ADHD scale.

Conclusions

The algorithms constitute an initial step in creating a framework for clinician-rated dimensional analyses of symptoms derived from the K-SADS-PL, but future studies are needed to further evaluate the construct validity of the remaining scales and the reliability and clinical utility of the method. We believe that our proposed algorithms offer a novel method of dimensional psychopathological assessment, which can be applied in multiple branches of child and adolescent psychiatry.

Keywords:

• Dimensional psychopathology
• K-SADS-PL
• ADHD
• Rasch models
• children

Acknowledgments

We are grateful to The Lundbeck Foundation for funding this study.

Ethical approval

The study was approved by the regional ethics committee, journal number H-B-2008–093.

Patient consent

Written consent was obtained from parent(s)/legal guardian(s).

Disclosure statement

BHE is part of the Advisory Board of Eli Lilly Denmark A/S, JanssenCilag, Lundbeck Pharma A/S and Takeda Pharmaceutical Company; and has received lecture fees from Bristol Myers Squibb, Otsuka Pharma Scandinavia AB, Eli Lilly Company, Boehringer Ingelheim Denmark A/S and Lundbeck Pharma A/S. JK has received grant funding from NIH, has served as a consultant for Pfizer and Otsuka Pharmaceuticals, and has a proprietary financial interest in the computer-administered KSADS (KSADS-COMP, LLC). The remaining authors declare no conflicts of interest.

Data availability statement

The structure of the REDCap database related to the COPSYCH study is available to all researchers upon request.

Additional information

Funding

This research was funded by The Lundbeck Foundation, grant number R243-2017-5.