Table 1.
Study | Design | Age range covered |
Measurement | Findings |
---|---|---|---|---|
Pingault et al. (4) | Twin cohort (N=8395 pairs) | 8 to 16 years (4 assessments) | Mother-reported DSM symptoms scales | 2 trajectories: - HI: marked decrease (6 to 2.9 symptoms) - Inattention: modest decrease (5.8 to 4.9 symptoms) |
Swanson et al (5) | ADHD and community controls (N = 485) | 7 to 10 years (3 assessments over 22 months) | Combined teacher- and parent-reported DSM symptoms via the SNAP | 3 trajectories: - Linear decreasing (34%) - Large initial symptom decrease followed by a sustained lower level (52%) - Initial increase followed by a return to baseline (14%) |
Riglin et al (6) | Population cohort (N=9757 children) | 4 to 17 years (7 assessments) | Parent-reported Strength and Difficulties Questionnaire (SDQ) | 4 trajectories (total ADHD symptoms): - Low/stable (~83%) - Intermediate (~8%) - Childhood-limited (~6%) - Persistent (~4%) |
Tandon et al. (7) | High risk cohort (ADHD, bipolar 1 or unaffected controls) (N=251 individuals) | 6 assessments over 10 years | Clinician-ascertained symptoms (K-SADS) | 4 trajectories (total ADHD symptoms): - Persisting low (~38%) - Rapid improvement (~16%) - Gradual improvement (~24%) - Persisting high (~22%) |
Döpfner et al. (8) | Combined 11 population cohorts: (N~2500) | 7 to 19 years (variable N of assessments) | Parent-reported ADHD Symptom Checklist | 3 trajectories for inattention and HI: - High (3%) - Moderate (13-19%) - Low (78-83%) - Moderate symptom and high HI trajectories improved - High inattention did not improve |
Murray et al (9) | Population cohort (N=1571) | 7 to 15 years (8 measurements) | Teacher-reported Social Behavior Questionnaire (8 DSM symptoms) | 4 trajectory groups for HI: - High/stable (24% of males, 9% of females) - Low/stable (63% of males, 81% of females) - High/increasing (13% of males) - Concave (10% of females) 3 trajectory groups for inattention: - High/stable (39% of males, 10% of females) - Low/stable (61% of males, 59% of females) - Moderate/stable (31% of females) - Gender differences noted: females showed large HI symptom increases in early adolescence; males elevated from childhood |
Malone et al. (10) | Cohort: at-risk for conduct problems (N=754) | ~9 to 15 years (3 observations) | Parent completed computer version of the Diagnostic Interview Schedule for Children | 3 symptom trajectories: - Low/stable (58%) - Convex (increase, then decrease) (18%) - Concave (decrease then increase) (24%) |
Larsson et al. (11) | Population twin (N=1450 pairs) | 8 to 17 years (3 assessments) | Parent-reported DSM symptoms checklist | 2 trajectories: - Low (91% for HI, 86% for inattention) - High/decreasing (9% for HI, 14% for inattention) |