乌鸦传媒

A study of adults with attention-deficit/hyperactivity disorder (ADHD) found no differences in clinical features between adults with a childhood diagnosis and adults with an adulthood diagnosis, suggesting that ADHD is a valid diagnosis in adults.¹

Previous studies have shown that many children with ADHD will continue to have symptoms and impairment in adulthood.^2,3

Not all adults with ADHD symptoms received an ADHD diagnosis during childhood. Retrospective and prospective studies have found that many adults with symptoms of ADHD did not meet the diagnostic criteria of ADHD by age 12 years, suggesting a distinct late-onset or adult-onset form of ADHD.^4,5

However, many of these adults had exhibited at least some symptoms of ADHD during childhood or adolescence, and the quality of evidence in these studies has been judged as mostly low.^4,5

Researchers have suggested several factors that make the interpretation of studies of ADHD in adults challenging. These include recall bias regarding childhood symptoms, false positives caused by misdiagnosis or substance use, errors from self-reports by adults, and the possibility of subthreshold ADHD in younger children who later developed ADHD as adolescents or adults.^4-7

The new study attempted to shed light on adult ADHD diagnosis and symptoms using data from patients referred to an adult ADHD clinic.¹

鈥淭he present study sought to provide additional information about the clinical features associated with adult ADHD in patients who have been diagnosed in childhood compared to those who were first diagnosed in adulthood,鈥� they explained in their paper. 鈥淲e hypothesized that differences in clinical features between these groups could yield insights into the validity of the later diagnoses and might provide clinicians with information useful in clarifying these diagnoses.鈥�¹

Study design

The study included patients who were clinically referred to the Massachusetts General Hospital Adult ADHD clinic between June 2016 and April 2022. Researchers had access to data for demographic descriptions, age of diagnosis, ADHD treatments, and diagnoses and treatments for other psychiatric disorders.

Patients referred to the clinic were assessed with 6 scales: the Adult ADHD Self Report Scale, Adult Self Report, Behavior Rating Inventory of Executive Function鈥揂dult Version, Barkley Emotional Dysregulation Scale, Mind Wandering Questionnaire, and Quality of Life Enjoyment and Satisfaction Questionnaire.

The researchers assigned patients by age at diagnosis to adulthood or childhood diagnostic groups. Those aged 18 years or older at diagnosis were the adulthood group, and patients aged 17 years or younger at diagnosis were the childhood group.

Patient characteristics

Investigators identified 134 adults with ADHD aged 18-55. A total of 56 (42%) received an ADHD diagnosis in childhood, with a mean age of 11.3 卤 3.7 years. Of these, 36 received a diagnosis of ADHD at age 12 or younger, and 20 received the diagnosis at age 13-17.

ADHD was diagnosed in adulthood in 78 (58%) of patients. The mean age at diagnosis in childhood was significantly younger than the mean age at diagnosis in adulthood (11.3 卤 3.7 vs 25.8 卤 8.3 years; P<.001).

Although the difference in age of diagnosis was significantly different between those with a childhood diagnosis and those with an adult diagnosis, as expected, the age of symptom onset was not significantly different between groups (P=.86). Age at symptom onset was available for 54 patients with an ADHD diagnosis in adulthood. Of these, 51 had symptom onset between pre-school and high school, and 3 in college or after college.

The groups also differed in some demographic characteristics. Of patients with a diagnosis in childhood, 48% were male. In contrast, only 31% of patients with an adult diagnosis were male (P=.04). Patients with a childhood diagnosis were younger at the age of referral compared with the patients with an adult diagnosis (27.4 卤 7.1 vs 32.2 卤 10.1 years; P=.003). Racial and ethnic identities were not significantly different between groups.

Treatment

Because gender and age of referral were significantly different between groups, analyses of treatments, clinical characteristics, and assessment scales were adjusted for these factors.

For patients with ADHD diagnosed in childhood who received treatment, treatment began at a mean age of 11.4 卤 4.1 years. For those who received a diagnosis in adulthood and received treatment, treatment began at a mean age of 26.0 卤 9.0 years (P<.001). 

However, the proportion that previously received ADHD treatment was not significantly different between groups. The 2 groups also did not significantly differ in the proportions of those who previously received other psychiatric medications (antidepressant, antianxiety, mood stabilizer, or antipsychotic). 

Similarly, no significant differences existed between groups in the proportions currently receiving any psychiatric medication or individual classes of medications (stimulant, non-stimulant ADHD, antidepressant, antianxiety, mood stabilizer, or antipsychotic medication).

Clinical features

No significant differences existed between patients with a childhood ADHD diagnosis and patients with an adult ADHD diagnosis on any of the 6 rating scales that assessed ADHD symptom severity, psychopathology, executive functioning, emotional dysregulation, mind-wandering, social competence, substance use, or quality of life. 

In addition, the highest educational level attained and proportion with employment were also similar between groups.

When the childhood diagnosis group was limited to those with a diagnosis at age 12 or younger rather than 18 or younger, there were still no significant differences in clinical features between the childhood and adulthood diagnosis groups.

Support for the ADHD diagnosis in adults

The researchers wrote in their paper that 鈥渙ur results provide further support for the validity of diagnoses of ADHD that are made in adulthood as these adults show a profile of clinical features that is very similar to those seen in adults diagnosed with ADHD in their youth.鈥� 

鈥淧erhaps our most important finding is that, among the adults first diagnosed in adulthood, 95% reported onset of symptoms of ADHD in their youth,鈥� they noted. 鈥淥ur results also suggest that, if adult-onset ADHD exists, it is rare.鈥�

The researchers also concluded that the diagnosis of ADHD in adulthood was unlikely to be due to disorders misdiagnosed as ADHD, such as substance use disorders. If so, they would have expected significantly higher rates of psychopathologic symptoms among patients with ADHD diagnosed in adulthood compared with those with ADHD diagnosed in childhood.

Limitations of the study are the small sample size and the use of clinically referred patients, who may be different from other individuals with ADHD.

Published: March 06, 2024