Curious to hear what others think, as this definitely aligns with my own experiences.

The original study is behind a paywall, but I'm trying to see if I can get a hold of the full text somehow. For now, here's the abstract.

Abstract

Objectives: Recent studies report a fluctuating course of attention-deficit/ hyperactivity disorder (ADHD) across development characterized by intermittent periods of remission and recurrence. In the Multimodal Treatment of ADHD (MTA) study, we investigated fluctuating ADHD including clinical expression over time, childhood predictors, and between- and within-person associations with factors hypothesized as relevant to remission and recurrence.

Methods: Children with DSM-5 ADHD, combined type (N = 483), participating in the MTA adult follow-up were assessed 9 times from baseline (mean age = 8.46) to 16-year follow-up (mean age = 25.12). The fluctuating subgroup (63.8% of sample) was compared to other MTA subgroups on variables of interest over time.

Results: The fluctuating subgroup experienced multiple fluctuations over 16 years (mean = 3.58, SD = 1.36) with a 6- to 7-symptom within-person difference between peaks and troughs. Remission periods typically first occurred in adolescence and were associated with higher environmental demands (both between- and within-person), particularly at younger ages. Compared to other groups, the fluctuating subgroup demonstrated moderate clinical severity. In contrast, the stable persistent group (10.8%) was specifically associated with early and lasting risk for mood disorders, substance use problems in adolescence/ young adulthood, low medication utilization, and poorer response to childhood treatment. Protective factors were detected in the recovery group (9.1%; very low parental psychopathology) and the partial remission group (15.6%; higher rates of comorbid anxiety).

Conclusions: In the absence of specific risk or protective factors, individuals with ADHD demonstrated meaningful within-individual fluctuations across development. Clinicians should communicate this expectation and monitor fluctuations to trigger as-needed return to care. During remission periods, individuals with ADHD successfully manage increased demands and responsibilities.