A systematic review and analysis of long-term outcomes in attention deficit hyperactivity disorder: effects of treatment and non-treatment

Shaw et al. BMC Medicine 2012, 10:99 http://www.biomedcentral.com/1741-7015/10/99 RESEARCH ARTICLE Open Access A systematic review and analysis of long-term outcomes in attention deficit hyperactivity disorder: effects of treatment and non-treatment Monica Shaw1†, Paul Hodgkins2*†, Hervé Caci3, Susan Young4, Jennifer Kahle5, Alisa G Woods6 and L Eugene Arnold7 Abstract Background: In childhood, attention deficit/hyperactivity disorder (ADHD) is characterized by age-inappropriate levels of inattentiveness/disorganization, hyperactivity/impulsiveness, or a combination thereof. Although the criteria for ADHD are well defined, the long-term consequences in adults and children need to be more comprehensively understood and quantified. We conducted a systematic review evaluating the long-term outcomes (defined as 2 years or more) of ADHD with the goal of identifying long-term outcomes and the impact that any treatment (pharmacological, non-pharmacological, or multimodal) has on ADHD long-term outcomes. Methods: Studies were identified using predefined search criteria and 12 databases. Studies included were peerreviewed, primary studies of ADHD long-term outcomes published between January 1980 to December 2010. Inclusion was agreed on by two independent researchers on review of abstracts or full text. Published statistical comparison of outcome results were summarized as poorer than, similar to, or improved versus comparators, and quantified as percentage comparisons of these categories. Results: Outcomes from 351 studies were grouped into 9 major categories: academic, antisocial behavior, driving, non-medicinal drug use/addictive behavior, obesity, occupation, services use, self-esteem, and social function outcomes. The following broad trends emerged: (1) without treatment, people with ADHD had poorer long-term outcomes in all categories compared with people without ADHD, and (2) treatment for ADHD improved long-term outcomes compared with untreated ADHD, although not usually to normal levels. Only English-language papers were searched and databases may have omitted relevant studies. Conclusions: This systematic review provides a synthesis of studies of ADHD long-term outcomes. Current treatments may reduce the negative impact that untreated ADHD has on life functioning, but does not usually ‘normalize’ the recipients. Keywords: ADHD, adult, childhood, outcomes, psychiatry, systematic Background In childhood, attention deficit/hyperactivity disorder (ADHD) is a psychiatric condition characterized by ageinappropriate levels of inattention, hyperactivity-impulsiveness or a combination of these problems [1,2]. The symptoms of ADHD often lead to functional impairment * Correspondence: † Contributed equally 2 Global Health Economics & Outcomes Research, Shire Development LLC, 725 Chesterbrook Boulevard, Wayne, PA, 19087, USA Full list of author information is available at the end of the article in multiple domains and lower quality of life. Therefore, in recent years the focus of intervention has expanded from ameliorating immediate symptoms of ADHD to improving functionality in several life domains. Moreover, although traditionally regarded as a childhood disorder, it is now clear that ADHD affects both children and adults. The worldwide prevalence of ADHD has been estimated at 5.29% [3,4] with approximately 4% prevalence in adults [5,6]. According to one meta-analysis, ADHD persists in about 65% of adults diagnosed as children if ADHD in partial remission is included [7], and in about 50% of © 2012 Shaw et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Shaw et al. BMC Medicine 2012, 10:99 http://www.biomedcentral.com/1741-7015/10/99 adults originally diagnosed as children according to a separate estimate [8]. Persistence of ADHD may be related to ADHD symptom severity, number of symptoms, ADHD symptom subtype, ADHD in relatives, psychosocial adversity, psychiatric comorbidities, and/or parental psychopathology [8-15]. Many adults with ADHD are undiagnosed and untreated. Research on ADHD in adulthood is relatively sparse [16] despite being recognized in adults as early as 1968 as ‘minimal brain dysfunction’ [17] and in 1972 as ‘hyperkinetic disorder’ [18]. Thus the negative outcomes reported by most follow-up studies may be a consequence of untreated symptoms. The short-term effect of ADHD treatment on symptoms is well characterized. Beyond this, the longer-term consequences have been the focus of numerous individual studies but comprehensive synthesis of the available data has yet to be conducted, thus the present systematic review was performed, focusing on comprehensive summary of long-term outcomes of ADHD. Short-term studies have demonstrated decreases in core symptoms with pharmacotherapy, but there is less evidence for longer-term benefits. Poor adherence and persistence on therapy, comorbidities, poor follow-up and difficulty in accessing consistent medication management from the healthcare system may contribute to difficulty in measuring longterm effects of medication [19,20]. Non-pharmacological interventions such as specialized training for parents of children with ADHD and cognitive behavioral therapy (CBT) for adults also reduce symptoms, and a multimodal approach may have greater effect [16,21]. Both non-pharmacological (that is, psychological, social, and educational) and pharmacological treatments for ADHD are recommended by the National Institute for Health and Clinical Excellence (NICE) guidelines [22] with treatment selection depending on the age of the individual and ADHD severity. Recently published European adult guidelines for the treatment of ADHD indicate that both medications and non-pharmacological interventions may be effective for adults with ADHD, although more research specifically in adults is needed [23]. The importance of long-term studies has been recognized for more than a decade [24]. ADHD treatment guidelines as well as conclusions drawn by health technology assessment agencies recognize that ADHD is potentially a lifelong condition with a profound effect on quality-of-life [22,25-32]. Several of these organizations recognize a need for further study of the long-term consequences of ADHD and of its treatment [22,29,30,32,33]. For example, the NICE guidelines state that ‘More research is needed on the influences on eventual outcome, and should include enquiry about the possible benefits (and risks) of early diagnosis and treatment’ [22]. Guidelines from the Oregon Health and Science University propose that ‘Good-quality evidence on the use of Page 2 of 15 drugs to affect outcomes relating to global academic performance, consequences of risky behaviors, social achievements, e (...truncated)