Diagnostic Instability of DSM–IV ADHD Subtypes: Effects of Informant Source, Instrumentation, and Methods for Combining Symptom Reports

Abstract

Using data from 123 children (aged 6–12 years) referred consecutively to a pediatric neuropsychiatry clinic by community physicians for assessment of Attention-Deficit/Hyperactivity Disorder (ADHD) and related problems, we investigated the effects of informant (parent, teacher), tool (interview, rating scale), and method for combining symptom reports (“and,” “or” algorithms), on the diagnosis of ADHD and its subtypes. Results indicated that as many as 50% of cases were reclassified from one subtype to another, depending on whether information was derived from one or two informants, a semistructured clinical interview and/or rating scale, and the algorithm used to combine informant reports. We conclude that the diagnosis of DSM–IV ADHD subtypes is capricious in that it is influenced by clinicians' decisions regarding informants, instrumentation, and method for aggregating information across informants and instruments.

Notes

^a Summary of data shown in Table 1 (Rowland et al., 2008).

^a Caucasian includes Italian, Portuguese, and Swedish; Asian includes those from South East Asia.

^b Missing race for 8 children.

^c Missing grade for 10 children.

^d Missing age for 1 child.

^a For example, case definition using the 6-4-6 AND rule requires six or more symptoms from the parent, at least four symptoms from the teacher, and at least six unduplicated symptoms. Subtype classification based on this rule, also requires at least six symptoms from the parent, at least four from the teacher, plus at least six unduplicated symptoms of inattention or hyperactivity/impulsivity. By contrast, the 6–4–6 OR rule for subtype requires six unduplicated symptoms regardless of informant.

Note: ADHD-C = Attention-Deficit/Hyperactivity Disorder Combined Type; ADHD-PI = Predominantly Inattentive Type; ADHD-HI = Hyperactive/Impulsive Type; SWAN = Strengths and Weaknesses of ADHD Symptoms and Normal Behavior; PICS = Parent Interview for Child Symptoms; TTI = Teacher Telephone Interview.

^a N = 107 participants with data from both parent and teacher SWAN rating scales.

^b N = 123 participants with data from both parent and teacher interviews.

^c N = 123 participants with data from parent interview plus teacher SWAN rating scale.

Note: ADHD-C = Attention-Deficit/Hyperactivity Disorder Combined Type; ADHD-PI = Predominantly Inattentive Type; ADHD-HI = Hyperactive/Impulsive Type; PICS = Parent Interview for Child Symptoms; TTI = Teacher Telephone Interview; SWAN = Strengths and Weaknesses of ADHD Symptoms and Normal Behavior.

Note: ADHD-C = Attention-Deficit/Hyperactivity Disorder Combined Type; ADHD-PI = Predominantly Inattentive Type; ADHD-HI = Hyperactive/Impulsive Type; PICS = Parent Interview for Child Symptoms; TTI = Teacher Telephone Interview; SWAN = Strengths and Weaknesses of ADHD Symptoms and Normal Behavior.