ADHD Symptoms in Adults

ADHD’s Vanishing (and Reappearing) Act

ADHD symptoms seem to disappear, return, worsen, and improve over the lifetime for many people. Here, an expert explains the influences thought to contribute to these fluctuations.

By Maggie Sibley, Ph.D. Updated on May 7, 2025
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In the fall of 2023, U.S. census data revealed a dramatic spike in the number of Americans who said they had serious difficulty remembering, concentrating, or making decisions during and immediately after the COVID-19 pandemic, The New York Times reported. What was going on here? Did people develop ADHD symptoms during the pandemic? Or did milder symptoms suddenly become “serious” amid the pandemic’s increased demands and daily disruptions?

Either possibility is plausible, according to research from the Multimodal Treatment of Attention Deficit Hyperactivity Disorder Study (MTA). It found that individuals without a childhood history of ADHD can sometimes develop symptoms later. When this happens, their ADHD symptoms tend to emerge in adolescence, rather than in adulthood. They also tend to be temporary.

Therefore, most adults today with new diagnoses of ADHD probably did not develop their symptoms in adulthood. Instead, they were likely missed or they had mild, non-clinical symptoms in childhood that became more impairing as life’s demands multiplied. The study suggested that ADHD is more likely to be missed in childhood in females and minorities. People with intellectual gifts or supportive environments are more likely to compensate for their ADHD in childhood, so symptoms appear milder.

[Watch: ADHD Across the Lifespan – How Symptoms Evolve and Fluctuate]

However, even individuals with mild, non-clinical symptoms can experience fluctuations that temporarily send their symptoms or impairment severity into the clinical range. ADHD is, therefore, a dynamic condition like hypertension, obesity, or social anxiety. In the case of ADHD, the neurocognitive risks are always present, but the clinical problems may only emerge sometimes. This is comparable to a person who struggles with weight gain but fluctuates in and out of the obesity range over the course of their lifetime.

The Role of Environmental Stressors on ADHD Fluctuations

Over the 16 years of the MTA study, most individuals with childhood ADHD experienced fluctuations in their ADHD, and about 90% said their symptoms improved to a point of clinical remission at some point. Yet, in most cases, their ADHD returned three to four years later. In other words, most individuals with ADHD can expect to go through years when their symptoms do not cause meaningful problems.

Do certain factors trigger these ADHD fluctuations? To find out, the MTA investigators researched whether environmental demands correlated with ADHD exacerbations. We speculated that increased stresses – like the number of hours worked and/or enrolled in school, the extent of childcare responsibilities, the presence of family and/or financial support – would be associated with higher levels of ADHD in participants.

We were surprised to find the opposite, as we explained in our paper published in the Journal of Clinical Psychiatry in October 2024. Yes, environmental demands were significantly associated with ADHD fluctuations. However, higher levels of demands were associated with remission of ADHD. In other words, people with ADHD may have been rising to the challenge when demands were high – when working or going to school more often, when living with fewer supports, and when becoming financially accountable for themselves or others.

[Read: Adult ADHD – A Guide to Symptoms, Signs, and Treatments]

The MTA investigators are still processing this finding. One explanation is that ADHD symptoms fade when situations create an urgent need to stay on track. It is also possible that, when people have lower ADHD symptom levels, they are able to take on greater responsibilities. Both interpretations may be true at the same time. It is difficult to fully disentangle these types of nuanced explanations using data.

The Triggers of Symptom Severity

The MTA data show that, while environmental demands and ADHD severity seem to be linked, they change in concert over time. Symptom fluctuations are possible and could conceivably influence ADHD prevalence rates. These fluctuations might also partially explain the increased help-seeking for ADHD during the COVID-19 pandemic. Additional research is imperative, especially in collaboration with people who have lived experience with ADHD.

Despite some uncertainties about the relationship between ADHD remission and the environment, the MTA findings are still important. They suggest that individuals with ADHD should track the environmental factors that turn the volume up or down on their symptoms. They can intentionally design their lives to fit with their environment by seeking out jobs, educational paths, people, activities, and lifestyles that accentuate their strengths.

For some people with ADHD, this may mean staying busy and keeping an active schedule to help modulate the impact of ADHD. This may also include working with practitioners to leverage a nuanced understanding of ADHD fluctuations when designing a treatment plan.

What Makes ADHD Worse, or Better? Next Steps

Margaret Sibley, Ph.D. is a professor of psychiatry and behavioral sciences at the University of Washington School of Medicine.

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