Attention Research Update

July 2011

"Helping parents, professionals and educators stay informed about new research on ADHD"

David Rabiner, Ph.D.  Associate Research Professor, Duke University

Does ADHD Medication Treatment in Childhood Increase Adult Employment?

Although ADHD used to be considered a disorder of childhood, follow-up studies indicate that between 30% and 60% of children with ADHD continue to experience symptoms and impairment in adulthood.  And, even when ADHD symptoms decline over time, many individuals continue to experience significant impairment in important areas of functioning.

For example, children with ADHD have poorer academic achievement as adolescents compared to their peers and this trend continues into adulthood. Research pertaining to occupational functioning is limited but available data clearly points to poorer employment histories in adults with ADHD. Predictors of occupational outcomes in individuals with ADHD have not been carefully investigated, however.

A recent study conducted in Norway with a large sample of adults with ADHD begins to address some of the important gaps in our knowledge of these issues [Halmoy et al.(2009). Occupational outcome in adult ADHD: Impact of symptom profile, comorbid psychiatric problems, and treatment. Journal of Attention Disorders, 13, 175-187]. 

Participants were 414 adults (198 women and 216 men) who were diagnosed with ADHD and whose clinician was seeking to treat them with stimulant medication.  As recently as 2005 in Norway, physicians looking to prescribe stimulant medication for adults needed to conduct a comprehensive assessment based on national guidelines and have their findings reviewed by an expert committee.  The committee needed to support the request to prescribe stimulants before the physician could do so. This was the required procedure even for individuals who were treated with stimulants prior to turning 18.  The 414 participants with ADHD were recruited from nearly 2000 adults whose information was sent for committee review between 2004 and 2006.  Comparison subjects (n=357) were drawn from a random sample of adults from across the country.

Both groups of adults completed a number of self-report measures to assess their current functioning in multiple areas including their educational attainment, occupational status, and psychiatric symptoms.  For the adults with ADHD, information on whether they were treated with stimulant medication as children was also obtained. 

- Results -

As expected, a number of important differences were found between adults with and without ADHD.  Key among these were the following:

- Only 23% of the ADHD group had attained a university level education compared to 59% of controls.

- 29% of the ADHD group had only a junior high school education vs. only 6% of controls.

- Lifetime rates of significant anxiety or depression was reported by 70% of the ADHD group vs. only 17% of controls.

- Lifetime problems with alcohol were reported by nearly 30% of the ADHD group compared to less than 3% of controls.

Group differences in the occupational realm were also striking.  At the time of the assessment, only 24.3% of adults in the ADHD group reported being employed compared to nearly 80% of the comparison adults.  More than half of adults with ADHD were either receiving disability or were in vocational rehabilitation compared to only 5% of comparison adults.  These differences were consistent across gender.

- Correlates of occupational outcome -

The researchers were interested in testing factors related to the occupational status of participants with ADHD.  The factors that they tested included severity of ADHD symptoms, ADHD subtype (inattentive, combined, or hyperactive-impulsive), symptoms of depression and anxiety, alcohol or drug problems, and whether the adult had been treated with stimulant medication in childhood.

After controlling for all variables in the model, only ADHD subtype and medication treatment in childhood was associated with current employment status.  Adults with the inattentive or combined subtype were more likely to be out of work than those with the hyperactive-impulsive subtype.  Thus, high rates of attention difficulties - either with or without hyperactivity - was a risk factor for being unemployed.

Results pertaining to childhood medication treatment were quite interesting.  Adults with ADHD who had not received medication treatment as children (n=329) were over three times as likely to be unemployed than those who had (n=75).  This finding remained even when educational attainment was controlled for.

Adults who had not been treated with medication in childhood also reported significantly higher rates of anxiety and depressive symptoms.

- Summary and implications -

Results from this study clearly indicate that adults with ADHD have poorer educational outcomes, report more psychiatric difficulties, and are more likely to be unemployed than other adults.  The difference in employment status was especially striking and highlights the significant impairment that frequently accompanies ADHD into adulthood.

An especially intriguing finding was the strong relationship between medication treatment in childhood and employment status in adulthood, as those who had been treated were far more likely to be employed.  What makes this finding particularly striking is that individuals treated with medication as children would be likely to have had more severe cases of ADHD to begin with, particularly since medication treatment is less common in Norway than in the US.  If this were the case, it would have worked against more positive occupational outcomes in adulthood, thus suggesting an especially important role for medication treatment.

The authors are careful to note that no definitive conclusion can be made about whether childhood medication treatment was responsible for higher employment rates.  One important reason for this is that there is no way to determine whether other factors associated with receiving treatment, rather than treatment itself, led to the obtained result.  For example, parents who obtained medication treatment for their child may have obtained other treatment services or supports for their child that contributed to greater occupational success.  This possibility, however, was not investigated and efforts to rule out this alternative explanation would have strengthened the study. 

It is also important to note that the lower employment rates and greater psychiatric difficulties of adults with ADHD in this study is likely to overestimate what is true for the general population of adults with ADHD.  Adults with ADHD in this study were struggling sufficiently to have their physician initiate the complex and time consuming procedure required in Norway to obtain permission to prescribe stimulants.  Thus, these adults were likely to be more impaired by their ADHD than the general population of adults with ADHD.  Had a more representative sample of adults with ADHD been included as participants, I suspect that differences with the comparison subjects would have been attenuated.

It is also the case that results found in one country may not necessarily generalize to other countries, and this should be kept in mind as well.

These limitations not withstanding, the findings reported highlight the important struggles that many adults with ADHD experience and emphasize the need for effective treatment of ADHD during the adult years.  It is especially interesting that adults who received medication treatment as children had better occupational outcomes as adults.  Although a causal relationship cannot be definitively established from these data, the importance of early identification and treatment of ADHD in promoting more positive long-term outcomes is certainly supported.

TInformation presented in Attention Research Update is for informational purposes only, and is not a substitute for professional medical advice.  Although newsletter sponsors offer products and services that I believe will be of interest to subscribers, sponsorship of Attention Research Update does not constitute a specific endorsement or guarantee of any company's product or services.

(c) 2011 David Rabiner, Ph.D.