Just been re-reading this paper which came out a few years ago but remains a very interesting read:-

Kessler RC, Adler L, Barkley R, et al. The prevalence and correlates of adult ADHD in the United States: results from the National Comorbidity Survey Replication. Am J Psychiatry. 2006;163:716-723.

In the US, there have been two attempts to capture large scale data about the prevalence – ie how common they are – of different psychiatric disorders in the general population. The first was the landmark Epidemiologic Catchment Area (ECA) survey of 1991 which used the Diagnostic Interview Schedule (DIS). The second was the National Comorbidity Survey (NCS) of 1994 which used a revised and expanded version of the DIS known as the World Health Organization (WHO) Composite International Diagnostic Interview. This information is obviously incredibly useful in allocating resources which of course are always scarce!! Unfortunately ADHD was not included in these scales which indicates how neglected adult ADHD has been despite it long being known that ADHD often does persist into adulthood.

Fortunately an adult ADHD screen was included in the National Comorbidity Survey Replication in 2004, and the researchers carried out clinical interviews with people who tested positive on the screen

These data could then be used to estimate the prevalence, comorbidity, and level of impairment of adult ADHD in the United States.

They estimate the prevalence of adult ADHD in the US to be 4.4% of the population and noted that it seemed to be more frequent in men, non Hispanic whites, the previously married, and the unemployed/disabled.

Looking at comorbid mental health disorders they found that of the people with ADHD; 38.3% had a diagnosable mood disorder; 47.1% had an anxiety disorder; 15.2% had a substance misuse disorder and a stonking 19.6% had an intermittent explosive disorder. Not surprisingly 53.1% of the women and 36.5% of the men had received treatment for mental health or substance related problems in the previous 12 months; however only 10.9% of the sample had received treatment for ADHD in the previous 12 months.

The research supports what we all know, that ADHD can very adversely affect people’s lives in all sorts of ways and comes with many mental health comorbidities and complications particularly when not diagnosed. Unsuccessful attempts to treat comorbid conditions in undiagnosed ADHD sufferers also wastes a lot of scarce resources. The researchers raise various questions:

  • Would early treatment of childhood ADHD influence these secondary adult disorders? It seems very likely but good quality research is needed to prove it.
  • Would adult treatment of ADHD have an effect on the severity or persistence of comorbid disorders? Several studies have documented high societal costs of anxiety, mood and substance misuse disorders but all ignored the role of comorbid ADHD – re-analyzing these figures might find that in fact ADHD accounts for possibly a substantial part of the effects previously thought to be due to these other disorders.