11.1 History of the Strengths and Weaknesses of Attention-Deficit/Hyperactivity Disorder—Symptom and Normal-Behavior Rating Scales: From 1990 to 2016

Objectives: The goal of this session is to provide a brief history of the rationale for the development of the Strengths and Weakness of ADHD symptoms and Normal-behavior (SWAN) rating scale, as well as a survey of its applications and evidence for its advantages over conventionally designed questionnaires. Methods: The mathematics of using statistical cutoffs based on 0 to 3 ratings of ADHD symptoms that define abnormal behavior (weaknesses) identified a potentially serious flaw for applications in the clinical practice. In the population, a high percentage of scores will be centered between 0 and 1, generating a highly skewed distribution. If strengths are not measured and scored, the variance of the truncated distribution is reduced. Statistical cutoffs based on total scores, z-scores, or T-scores and the assumptions of normality (e.g., mean + 1.65 SD) may over-identify or under-identify extreme cases in the skewed distribution. By rewording the items, the SWAN scale captured the opposite of weaknesses (strengths) by expanding the four-point scale of symptom presence (0 ="not at all" to 3 ="very much") to a sevenpoint scale with symptoms denoted by weaknesses (0 ="average" to 3 = "far below average") and the opposites by strengths ("far above average" =-3). The first papers presenting the SWAN were rejected. An early presentation in 2000 to the ADHD Molecular Genetics Network led to a group consensus to adopt the SWAN, although this decision was later overturned. However, several investigators used the SWAN before its eventual official publication more than a decade later. Results: Many published studies show the value of capturing variance associated with both strengths and weaknesses to generate a near-normal distribution of ratings in epidemiological sample groups. The non-normal distributions of other scales [Conners; DuPaul; Swanson, Nolan and Pelham (SNAP); Strengths and Difficulties Questionnaire; Child Behavior Checklist; and etc.] and the application of the SWAN to measure ADHD as a dimension will be presented and discussed. Conclusions: With a focus on ADHD, the SWAN provides a model by which the symptomatology specified for DSM-5 diagnoses can be converted into behaviors that extend from nonclinical to clinical ranges. The data reviewed across studies demonstrate the potential advantages of using the SWAN in research studies.