There were 50 ADHD patients (40 boys and 10 girls) with a mean age of 7.84 ± 1.64 years. Fifteen of them were inattentive type, 11 were hyperactive-impulsive type, and 24 were combined type. Using a cutoff point of 60 on the aggression scale of the CBCL, patients were also categorized into aggressive and non-aggressive subtypes: 28 into the aggressive subtype and 22 into the non-aggressive subtype. There was no significant difference in the categorization rates of patients with aggression between the DSM-IV subtypes. Table presents and compares the demographic data and ADHD symptom measurements of the CBCL, SNAP-IV, ADHD-RS and CPT between DSM-IV subtypes at baseline, and which between aggressive and non-aggressive patients at baseline are displayed in Table .
Demographic data and ADHD symptoms measurements for ADHD patients with DSM-IV subtypes at baseline
Demographic data and ADHD symptoms measurements for ADHD patients with aggression and without aggressive at baseline
Among the 50 ADHD patients at the initial visit, 42, 33, and 30 patients remained in the study at visit 2, 3, and 4, respectively. The reasons for premature discontinuation were adverse events (N = 3), non-compliance (N = 4), withdrawal of consent (N = 2), and lost to follow-up (N = 11). There were no significant differences in discontinuation rates between DSM-IV subtypes ADHD patients (p = 0.905), or between aggressive and non-aggressive patients (p = 0.606). All patients were drug-free at visit 1 (baseline). The mean dose of MPH was 9.87 ± 5.09 mg (0.37 ± 0.20 mg/kg) at visit 2, 14.88 ± 6.97 mg (0.48 ± 0.29 mg/kg) at visit 3, and 13.00 ± 7.52 mg (0.46 ± 0.24 mg/kg) at visit 4, respectively.
To condense the number of ADHD measures and reduce type I errors, a principal components analysis was performed. Four factors yielding eigenvalues greater than 1.00 were retained for varimax rotation. The weights for the measures of each factor are listed in Table . The resultant factors were labeled on the basis of their clinical meaning: CPT distraction (factor 1), CPT impulsivity (factor 2), clinical hyperactivity (factor 3), and clinical inattention (factor 4). These 4 factors had eigenvalues of 3.99, 2.21, 1.44, and 1.16, respectively, and accounted for 79.93% of the total matrix variance.
The structure of factors produced by principal components analysis of ADHD measuresa,b.
During the 6-month treatment, there were significant improvements in CPT impulsivity (F = 17.22, p < 0.001), clinical hyperactivity (F = 19.85, p < 0.001), and clinical inattention (F = 26.06, p < 0.001). However, CPT distraction was not improved (F = 0.80, p = 0.497), and there were no significant differences between any paired visits. For the rest three factors aforementioned, the trends of changes were the same during 6 months. There were significant improvements from V1 to V2, and V2 to V3, but no significant differences from V3 to V4. The oppositional scores of SNAP-IV significantly changed over 6 months (F = 22.74, p < 0.001), and there were significant differences from V1 to V2, and V3 to V4.
In terms of the differences between DSM-IV subtypes, Figure summarizes the results of changes over time for each of the four dependent factors. For CPT distraction, CPT impulsivity, and clinical inattention, there was no significant difference between the subtypes and no significant interaction between subtypes and visits in these factors. For clinical hyperactivity, there was significant difference (F = 4.11, p = 0.024) between subtypes, but no significant interactions between DSM-IV subtypes and visits.
Figure 1 Changes in ADHD symptom composite scores between DSM-IV subtypes of ADHD patients during 6 months of real-world clinical treatment. There were no significant differences between DSM-IV subtypes in CPT distraction (a), CPT impulsivity (b), and clinical (more ...)
For the differences between aggressive and non-aggressive patients, the results were more diverse in each factor. Figure demonstrate the results of changes over time for each of the four dependent factors. For CPT distraction, there was no significant difference between subtypes, but there was significant interaction between subtypes and visits (F = 3.05, p = 0.031). The changes from V1 to V4 in non-aggressive patients were significantly greater than aggressive patients (t = 2.27, p = 0.028). Similarly for CPT impulsivity, there was no significant difference between subtypes, but there was also significant interaction between subtypes and visits (F = 3.53, p = 0.017). The changes from V1 to V4 in non-aggressive patients were significantly greater than aggressive patients (t = 2.39, p = 0.021). For clinical hyperactivity, there was a significant difference between subtypes (F = 7.87, p = 0.008), but no significant interaction between subtypes and visits. For clinical inattention, there were neither significant differences between subtypes nor an interaction between subtypes and visits.
Figure 2 Changes in ADHD symptom composite scores between aggressive and non-aggressive ADHD patients during 6 months of real-world clinical treatment. There was a significant difference in clinical hyperactivity (g) between aggressive subtypes (F = 7.87, p = (more ...)