The majority of investigations into the long-term outcomes of children with ADHD have been in males (presenting primarily with hyperactivity and impulsivity), and, accounting for normative gender differences in developmental outcomes, these findings may not be fully generalisable to females with ADHD.
This study aimed to investigate which long-term outcomes are associated with childhood ADHD (combined and inattentive types) among females, and to examine whether persistence of childhood ADHD predicts worse outcomes than childhood-limited ADHD. Participants were followed prospectively for 16 years.
The study recruited girls aged 6–12 years from San Francisco East Bay schools, mental health centres and paediatric practices, as well as through advertisements, to participate in research summer camp programmes in 1997, 1998 and 1999. A total of 140 girls with confirmed ADHD, and 88 age- and ethnicity-matched comparisons, were selected to participate. Participants were initially assessed at baseline (Wave 1 [W1]), and then again 5 years (Wave 2 [W2]) and 10 years later (Wave 3 [W3]), when participants and their parents were interviewed, answered questionnaires and completed neuropsychological testing. Wave 4 (W4), 16 years following W1, saw participants invited for a clinic-based assessment.
Long-term outcomes assessed included:
- Psychopathology and harmful behaviours: ADHD diagnosis; internalising and externalising problems; depression; substance use; self-injury.
- Impairments and attainments: self, parent and clinician ratings; academic achievement; health; social relationships; driving behaviour; and other measures.*
To assess the impact of ADHD persistence on outcomes, the researchers categorised participants with confirmed ADHD into three groups:
- Desisters: those who met ADHD criteria at W1 but not at W3 and not at W4 (n=32; 26.0%).
- Partials: those who met ADHD criteria at W1 and at W3 or W4 (n=38; 30.9%).
- Persisters: those who met ADHD criteria at all three time points (n=53; 43.1%).
A series of 35 analyses of covariance (ANOVAs) and 8 chi squared tests assessing W4 outcomes across the three ADHD groups resulted in statistically significant (p≤0.001) differences between groups across 29 measures.† After adjustments were made for a pre-defined set of covariates, all differences remained significant (p≤0.05), except for the Wechsler Individual Achievement Test (WIAT) Math (p=0.069) and self-reported social impairment (p=0.171).
Pairwise comparisons also found differences between ADHD groups and the comparison group across multiple impairment measures:
Psychopathology and harmful behaviours
- No overall differences were reported in adult psychopathology between the comparison group and desisters, whereas partials had slightly higher mean levels of internalising and externalising problems and self-injury than comparisons, and persisters showed much higher levels of these problems than comparisons.
- Patterns for internalising and externalising problems were similar between the ADHD groups. Small differences existed between desisters and partials, with medium-to-large differences between desisters and persisters, and medium-sized differences between partials and persisters.
- When looking at self-injury, those classified as partials or persisters had a large difference relative to desisters, whereas mean differences in substance use between all groups were very small.
- Compared with comparison participants, girls with ADHD had a medium to large deficit in educational achievement, although differences between the ADHD groups were small.
- Overall, comparisons had slightly better employment outcomes than desisters and partials, but much better outcomes than persisters; the overall differences in employment outcomes between desisters and partials were very small, and both desisters and partials had better outcomes than persisters.
- When considering overall impairment, desisters were statistically similar to the comparison group, but partials and persisters had worse outcomes.
- Among girls with ADHD, persisters had much greater impairment overall than desisters, with partials exhibiting less impairment than persisters, but greater impairment than desisters.
- While there were only small differences in health outcomes between the ADHD groups, all ADHD groups had worse health outcomes compared with the comparison group.
- Persisters had worse social outcomes than comparison participants and desisters.
- No notable differences were noted in driving measures between any of the four groups, regardless of ADHD status.
Limitations of the study included: 1) examination of social skills was omitted when looking at relationship experiences and impairment; 2) substance-use severity was examined, but not the substance-use disorders themselves; 3) the sample was not clinic-referred or nationally representative, but was based on a suburban community referral; 4) for a meaningful understanding, the study needs to examine mediators and moderators of the findings — this will be discussed in future papers.
The authors concluded that, in most domains assessed, the impact of childhood ADHD on adult outcomes in females is defined by its persistence, such that those with greater persistence of ADHD had significantly increased risks across numerous domains, including internalising, externalising, self-injury, occupational attainment, social problems and overall impairment.
Read more about the impact of ADHD persistence from childhood to adulthood here
*Other measures were: incarcerated/arrested since W3; highest educational degree; years of education; receipt of public assistance; current employment status; hours worked per week; current monthly earnings; problems at work; unplanned pregnancies; overall health; and history of psychiatric hospitalisations
†Adult Self-Report (ASR) Internalising; Adult Behavior Checklist (ABCL) Internalising; Beck Depression Inventory (BDI) total; Structured Clinical Interview, non-patient edition for DSM-IV-TR (SCID) mood diagnosis; ASR Externalising; ABCL Externalising; suicide attempts; any non-suicidal self-injury; highest educational degree earned; years of education; WIAT Math; WIAT Reading; clinician-, parent- and self-reported educational functioning; problems at work; clinician-, parent- and self-reported functioning at work; BMI (body mass index); unplanned pregnancies; poor overall health; clinician-, parent- and self-reported social impairment; clinician-, parent- and self-reported overall impairment; and psychiatric hospitalisations
Owens EB, Zalecki C, Gillette P, et al. Girls with childhood ADHD as adults: cross-domain outcomes by diagnostic persistence. J Consult Clin Psychol 2017; 85: 723-736.