A Population-Based Study of Attention Deficit/Hyperactivity Disorder Symptoms and Associated Impairment in Middle-Aged Adults

Easteal S (2012) A Population-Based Study of Attention Deficit/Hyperactivity Disorder Symptoms and Associated Impairment in Middle-Aged Adults. PLoS ONE 7(2): e31500. doi:10.1371/journal.pone.0031500 A Population-Based Study of Attention Deficit/ Hyperactivity Disorder Symptoms and Associated Impairment in Middle-Aged Adults Debjani Das 0 Nicolas Cherbuin 0 Peter Butterworth 0 Kaarin J. Anstey 0 Simon Easteal 0 Efthimios M. C. Skoulakis, Alexander Flemming Biomedical Sciences Research Center, Greece 0 1 John Curtin School of Medical Research, The Australian National University , Canberra , Australian Capital Territory, Australia, 2 Centre for Research on Ageing, Health and Wellbeing, Australian National University , Canberra , Australian Capital Territory , Australia Attention deficit/hyperactivity disorder (ADHD) is the most prevalent childhood psychiatric condition. It frequently persists into adulthood and can have serious health and other adverse consequences. The majority of previous adult ADHD studies have focused on young adults so that relatively little is known about ADHD symptoms and their effects in mid and late life. In addition, effects of subclinical levels of attention deficit and hyperactivity have not been studied in detail. In this study we investigated ADHD symptoms and related impairment in a large population-based sample of middle-aged Australian adults (n = 2091; 47% male). Applying the WHO adult ADHD Self Report Screener (ASRS) we observed that 6.2% of participants had scores that were previously associated with ADHD diagnosis. No significant gender difference in the distribution of ASRS scores was observed. Multiple regression analyses indicated strong positive correlations between symptoms of ADHD and depression/anxiety and significant negative associations (p,0.01) with employment, financial stress, relationship quality, health and well-being measures in this age group. Importantly, associations were highly significant even when few ADHD symptoms were reported. Compared to the hyperactivity component, the inattention trait was particularly strongly associated and remained significant after controlling for depression/anxiety symptoms. Our study confirms previous findings and significantly adds to existing literature especially for an age-group that has not been well-studied. Our results suggest that ADHD symptoms continue to be associated with ill-health and functional impairment in mid-life and are, therefore, likely to be a major, previously unrecognized source of late-life morbidity with associated social and economic costs. Thus, there is a compelling need for better understanding and development of age-appropriate approaches to the diagnosis and treatment of ADHD in mid- to late-life. - Funding: This study was supported by the National Health and Medical Research Council of Australia (Unit Grant 973302, Program Grant 179805, Project Grant 418039). DD is funded by National Health and Medical Research Council of Australia Capacity Building Grant No. 418020 in Population Health Research, NC is funded by National Health and Medical Research Council of Australia Research Fellowship No. 471501, PB is funded by National Health and Medical Research Council of Australia Research Fellowship No. 525410 and KA is funded by National Health and Medical Research Council of Australia Research Fellowship No. 366756. The funders did not have any role in the design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Attention Deficit/Hyperactivity Disorder (ADHD) is a treatable neuropsychiatric disorder characterized by inattention, excessive motor activity and impulsivity [1], which begins in childhood and can persist across the lifespan. However, symptom patterns change with age and become less obvious and specific in adults [2]. Most adults predominantly exhibit problems with inattention, which manifest as disorganization, forgetfulness, unreliability, and difficulty in planning, task completion, task shifting and time management [2,3]. These symptoms adversely affect multiple life domains with serious negative impact on functioning in day-to-day life. Adult ADHD is also associated with a wide range of other disorders, such as mood and substance use disorders [2,4] and its detrimental effect result in substantial public health and other costs [59]. A recent meta-analysis study reported that the prevalence estimate of adult ADHD is 2.5% with a significant interaction effect of age and gender on the estimate [10]. Earlier studies had reported estimates between 1.0 and 7.3% [1122]. Although the prevalence of ADHD is thought to decrease with age; these estimates suggest that ADHD is one of the most common adult psychiatric disorders. Moreover, the true population prevalence of the disorder is likely to be higher since under-reporting of symptom severity is common and because of problems with current diagnostic methods applied to adults [2,23,24]. Clinical diagnosis of ADHD typically follows categorical definitions codified in The Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Text Revision (DSM-IV-TR) [25]. However, accumulating evidence strongly supports ADHD symptoms as being dimensional rather than categorical with the disorder existing at the extremes of symptom distributions [26]. It has been suggested that the dimensional approach is likely to capture clinical and research data far more effectively than the categorical approaches currently used [27]. ADHD symptoms are also quite common; Arcos-Burgos et al. (2007) [28] reported that nearly 60% of the general population displays some symptoms of inattention and hyperactivity. Furthermore, individuals with ADHD symptoms who never meet the DSM threshold for diagnosis are also significantly impaired and have a milder form of the disorder [29,30]. However, effects of few and/or mild symptoms have not been studied in detail. While awareness of adult ADHD has increased over the last decade, we know relatively little about the disorder in older adults. Few studies [10,21,22,31] have included individuals over the age of 45 years when estimating prevalence rate in adult populations. Guldberg-Kjar and Johansson (2009) [32] studied self-rated ADHD symptoms in 6580 year old Swedish adults and reported a prevalence rate of 3.3%, which is comparable to that in the younger age-groups. It has also been suggested that older adults with ADHD suffer from cumulative consequence of the disorder over the lifespan, which affects quality of life at late-age [33]. Thus, persistence of ADHD and its adverse consequences into late life has important public health implications. Since ADHD is a treatable condition, greater emphasis on its diagnosis and treatment in older people might result in sizeable reductions in late-age morbidity. There has been increasing recognition that midlife (...truncated)