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FACTOR STRUCTURE OF DSM-IV SYMPTOMS IN ADULTS
Citation:
FERNANDEZ, M., K. HARDY, S. KOLLINS, AND S. B. MCMASTER. FACTOR STRUCTURE OF DSM-IV SYMPTOMS IN ADULTS. Presented at American Academy of Child Adolescent Psychiatry Annual Meeting, Boston, MA, October 23 - 28, 2007.
Impact/Purpose:
research presentation
Description:
Objective: In up to 50% of clinic-referred samples of children, ADHD symptoms persist into adulthood,1-3 with the prevalence of adult ADHD currently estimated at 4.4%4. Similar to the pervasive impairments experienced by children with ADHD, adults with ADHD are less likely to complete high school, less likely to be employed, and report lower rates of familial, social, and occupational satisfaction relative to their peers5. Given the rates of this disorder in adults and its associated impairments, it is essential to consider the validity of the constructs believed to underlie these difficulties. The DSM-IV field trials identified diagnostic criteria for ADHD; however, the results were based on a sample of predominantly male children and adolescents6. As a result, current criteria are largely defined as developmentally inappropriate behaviors (e.g., runs about/climbs excessively). Thus, the applicability to adults of criteria developed with children remains questionable. Several studies have been conducted to examine the validity of the current factor structure of ADHD in adults7-10, predominately with nonclinical samples. Overall, results suggest variability in factor structure depending on the population of adults examined. One consistent finding across studies, however, is that the factor structures identified for adults differ from the two-factor solution currently used in the DSM-IV-TR. Specifically, a three-factor model has been supported in some population-based studies, reflecting separate dimensions of inattention, hyperactivity, and impulsivity. Given that the trajectory of ADHD symptoms appears to shift with age, the purpose of this study was to examine the factor structure of ADHD in a clinic-referred sample of adults, using both self- and observer-report of DSM-IV symptoms. Method: Reports of ADHD symptoms were obtained from participants (n = 274) and observers (n = 274). Individuals who provided self-report ratings were referred for assessment of attention problems to a large medical center in the southeastern United States, and ranged in age from 18 to 70 years (mean age = 31.9, SD = 12.49). The 18 DSM-IV symptoms were assessed using the Conners’ Adult ADHD Rating Scale – Self-Report: Long form (CAARS-S:L) and the Conners’ Adult ADHD Rating Scale – Other-Report: Long form8. Data were submitted separately for participants and observers to confirmatory factor analyses (CFA) using SAS version 9.1.3. Three different models were assessed: a three-factor model representing dimensions of inattention, hyperactivity, and impulsivity, a two-factor model representing the DSM-IV dimensions of inattention and hyperactivity/impulsivity, and a single factor model of all ADHD symptoms. Results: All models tested yielded poor fit according to several widely-used fit indices, including the chi-square test, Bentler’s Comparative Fit Index (CFI), root mean square errors of approximation (RMSEA11)and Bentler and Bonett’s12 Non-normed Fit Index (NNFI; see Table 1).