The diagnosis of ADHD in children should be made on the basis of clinical interviews with parents and teachers who provide information on the child’s behaviour in different settings, such as home, school or with peers (NICE 2018). In cases where such extensive assessment is not possible, such as in epidemiological or treatment studies, parent-rated questionnaires are frequently used as an alternative to diagnose childhood ADHD. However, the validity of these questionnaires for determining the presence and severity of ADHD symptoms remains unclear. This study aimed to address this unanswered question by determining the validity of a parent-report questionnaire as a research tool for rating ADHD symptoms in children.
Children with ADHD* (aged 6–13 years) were recruited from three different mental health care centres in the Netherlands. Using Cohen’s kappa and Pearson correlation, the study examined the agreement between parent-reported Swanson, Nolan and Pelham Questionnaire-IV (SNAP-IV) and clinical judgement using the semi-structured parent interview, Parent Interview for Child Symptoms (PICS-IV). Regression analyses were also used to examine the factors that may be associated with the level of agreement.
- SNAP-IV† is an 18-item ADHD symptom scale (nine inattentive and nine hyperactive-impulsive Diagnostic and Statistical Manual of Mental Disorders – 4th Edition [DSM-IV] symptoms), which is rated on a 4-point scale (0–3). The questionnaire assesses symptoms from the previous week, as rated by the child’s primary caretaker.
- PICS-IV‡ is a semi-structured clinical interview with the child’s parents that covers the full range of DSM-IV symptoms of ADHD and symptoms of oppositional defiant disorder (ODD). Each symptom is rated by the clinician on a 4-point scale (0–3) for the previous 6 months.
Results from the study demonstrated moderate levels of parent–clinician agreement for severity of overall ADHD (r = 0.42, 95% confidence interval [CI] 0.20–0.60; p ≤ 0.009) and for hyperactive-impulsive symptoms (r = 0.54, 95% CI 0.35–0.69; p ≤ 0.009). However, no statistically significant effect was observed for inattentive symptoms (r = 0.33, 95% CI 0.01–0.53; p = 0.01). Furthermore, no significant kappas were observed with regard to agreement on types of ADHD (kappa = 0.14, n = 52, 95% CI –0.05–0.34; p = 0.067) and on the presence/absence of any ADHD type (kappa = 0.19, n = 52, 95% CI –0.15–0.53; p = 0.139), which suggested poor levels of parent–clinician agreement.
In explorative analyses examining the factors that may impact levels of parent–clinician agreement, a number of factors were identified as candidates for agreement on total ADHD severity:
- Total ADHD severity: candidate factors included the child’s current medication use (t = 1.81; p = 0.076), parenting stress (PSI-SF; r = 0.21; p = 0.090), and the total number of ADHD symptoms according to the PICS-IV (r = –0.24; p = 0.053).
- ADHD inattentive severity: candidate factors included parenting stress (PSI-SF; r = 0.20; p = 0.098) and number of inattentive ADHD symptoms according to the PICS-IV (r = –0.31; p = 0.012).
- ADHD hyperactive-impulsive severity: candidate factors included the child’s current medication use (t = 1.774; p = 0.081), number of hyperactive-impulsive symptoms based on the PICS-IV (r = –0.32; p = 0.010) and total number of ADHD symptoms according to the PICS-IV (r = –0.24; p = 0.051).
Exploratory analyses also demonstrated that parents were aligned with clinicians in evaluating the presence and severity of the total hyperactive and impulsive symptoms, but not in assessing the severity of inattentive symptoms of their child:
- Total ADHD severity: difference between SNAP-IV and PICS-IV was 6.3 points (standard deviation [SD] 9.1; range –11.4–27.0), with 20.9% of primary caretakers scoring lower than clinicians.
- ADHD inattentive severity: difference between SNAP-IV and PICS-IV was 4.7 points (SD 5.4; range –7.4–16.0), with 16.4% of caretakers scoring lower than clinicians.
- ADHD hyperactive-impulsive severity: difference between SNAP-IV and PICS-IV was 1.7 points (SD 5.1; range –9.0–13.0), with 38.8% of parents/caretakers scoring lower than clinicians.
The most important limitations associated with this study were the relatively small sample size and missing data. Furthermore, the participants included in the study were diagnostically complex and mostly medicated, which may have resulted in selection bias and subsequent overestimation of ADHD symptom severity by parents. Differences between the PICS-IV and SNAP-IV may have also led to a limitation in the comparability between the two measures.
The authors concluded that these findings suggest that parent-report questionnaires may be acceptable to rate the overall severity of ADHD symptoms in treatment-effect studies. However, parent-report questionnaires may be less valid to establish whether an ADHD diagnosis is present or absent, as is commonly done in epidemiological studies. The authors suggested that the use of parent questionnaires for diagnostic purposes should be reconsidered, and that continuous ratings of ADHD severity may be more appropriate.
*At the time of referral to the study, all children met diagnostic DSM-IV-TR criteria for ADHD, as confirmed by clinical interviews with parents and teachers. To be eligible to participate in the study, children had to have a full-scale, verbal and performance IQ >70. Comorbidity was not an exclusion criterion
†Reliability of SNAP-IV has been found to be high (coefficient alpha of 0.90 and 0.79 for inattentive symptoms and hyperactive-impulsive symptoms, respectively)
‡Inter-reliability of the PICS-IV for an ADHD diagnosis has been shown to be good (kappa = 0.73). Kappas for individual ADHD symptoms range from 0.50–0.96. Intra-class correlation coefficients for overall symptoms scores are also high (inattentive symptoms: 0.93; hyperactivity-impulsivity symptoms: 0.97)
NICE guideline 2018. Attention deficit hyperactivity disorder: diagnosis and management. Available at: https://www.nice.org.uk/guidance/ng87. Accessed April 2019.
Nobel E, Brunnekreef JA, Schachar RJ, et al. Parent-clinician agreement in rating the presence and severity of attention-deficit/hyperactivity disorder symptoms. Atten Defic Hyperact Disord 2019; 11: 21-29.