Adult-Onset ADHD

Understanding the controversy

A balanced exploration of the concept of ADHD that emerges in adulthood, contrasting it with the more common childhood-diagnosed ADHD.

A brainworkup logo for adult ADHD.


Attention-Deficit/Hyperactivity Disorder (ADHD), traditionally considered a childhood disorder, has been increasingly recognized in adults. Recent studies, including those by the Multimodal Treatment of ADHD (MTA) group, have sparked a debate on the validity of “Late Onset ADHD” or “Adult Onset ADHD.” This page aims to explore the evidence for and against this concept and to understand how it differs from ADHD diagnosed in childhood.

What is Late Onset ADHD?

Late Onset ADHD refers to the diagnosis of ADHD in adults who did not exhibit typical symptoms during childhood. This challenges the long-standing view that ADHD is a developmental disorder originating in childhood.

The Case For Late Onset ADHD

  1. Emerging Adult Symptoms:
    • Some studies suggest that certain individuals may develop ADHD symptoms in adulthood, without a clear history of these symptoms in their childhood.
  2. Neurodevelopmental Changes:
    • Research indicates possible neurodevelopmental changes in adulthood that could trigger ADHD symptoms.
  3. MTA Group Findings:
    • Recent findings by the MTA group and others support the existence of Late Onset ADHD, noting distinct neurobiological and behavioral patterns in adults diagnosed later in life.

The Case Against Late Onset ADHD

  1. Diagnostic Overshadowing:
    • Skeptics argue that what is diagnosed as Late Onset ADHD may be a misinterpretation of symptoms of other psychological conditions or life stressors.
  2. Recall Bias:
    • Critics highlight the potential for recall bias in adults, where childhood symptoms might be underreported or overlooked.
  3. Methodological Concerns:
    • Some studies on Late Onset ADHD face methodological limitations, raising questions about the validity of their findings.

Differences from Childhood-Diagnosed ADHD


  • Childhood ADHD: Typically characterized by more overt symptoms like hyperactivity.
  • Late Onset ADHD: More subtle symptoms, often internalized such as inattention and disorganization.

Neurobiological Factors

  • Childhood ADHD: Strong genetic components and early neurodevelopmental deviations.
  • Late Onset ADHD: Possible links to lifestyle factors and adult neurodevelopmental changes.

Response to Treatment

  • Childhood ADHD: Generally responsive to traditional ADHD treatments and interventions.
  • Late Onset ADHD: May require different therapeutic approaches, considering comorbid conditions and adult life context.


The debate on Late Onset ADHD highlights the complexity of ADHD as a whole and underscores the need for more nuanced diagnostic criteria and treatment approaches. Ongoing research, including contributions from the MTA group, continues to shed light on this evolving topic.


  • MTA Group Studies on ADHD
  • Recent Research on Neurodevelopmental Changes in ADHD
  • Comparative Studies on Childhood vs. Adult Onset ADHD