Title: Attention‐deficit hyperactivity disorder in a life perspective
Abstract: There is no doubt that attention-deficit hyperactivity disorder (ADHD) is a very common mental disorder that originates in childhood and continues into adulthood with a debilitating course in many afflicted individuals. The term ADHD is a precise description of the cardinal features of impaired attention and overactivity, with disinhibition and impulsivity being important underlying or associated characteristics. While ADHD is based on Diagnostic Statistical Manual (DSM) criteria and according to various international surveys and our own study (1) amounts to 2–5% of the child population, the term hyperkinetic disorder (HD) reflects the ICD-nomenclature and implies a more restricted core group of more severely afflicted subjects leading to lower prevalence rates. In particular, the differentiation between an inattentive type or attention-deficit disorder without hyperactivity (ADD) and a combined type (ADHD) that was first introduced in DSM-III, then skipped in DSM-III-R, and reintroduced in DSM-IV, but not represented in ICD-10, may have led to a large and unreliable increase in diagnoses of ADHD and ADD in clinical practice. Given the wide popularization of the ADD concept, both in the professional and lay public, there is sufficient concern that the still limited validation of the ADD concept and a lack of recognition of the many issues of differential diagnoses, with attention-deficit being a core symptom in many mental disorders, may have led to an increase in false-positive cases in clinical practice. On the other hand, long-term outcome observations of ADHD children have clearly shown that besides a high rate of antisocial personality and substance abuse disorders, there is also a considerable proportion of persisting ADHD with hyperactivity remitting more frequently than attention-deficit, so that a residual type of ADD may result. Originating from child outcome studies, the interest in adult manifestations of ADHD has emerged only in the recent past whereas children with ADHD or HD have been identified for many decades. With a lack of precise epidemiological data, the prevalence of adult ADHD has been estimated to amount to 2–3%. Differential diagnoses in adult ADHD subjects include depression, bipolar disorder, anxiety disorder, substance abuse disorder, schizophrenia, and various personality disorders, including most notably antisocial and borderline personality disorder. Thus, a thorough assessment considering these co-morbid conditions by a skilled expert is essential in order to identify true ADHD patients and implement adequate treatment. The present issue of this journal contains a study by Hesslinger et al. (2) dealing with these important issues of differential diagnosis and co-morbidity in adult ADHD. The study expands our knowledge by focussing on the link between ADHD and recurrent brief depression (RBD) and showing that RBD is a very common co-morbid lifetime condition, whereas the reverse association is less common. As the authors state, this association of adult ADHD with RBD may have important implications for medical treatment. Pharmacotherapy has been the major avenue of treatment of ADHD children for decades and the central role of stimulants has been convincingly documented again in one of the most extended and thorough studies on treatment outcome that, so far, has been performed with children. Including 579 ADHD children the Multimodal Treatment of ADHD study has clearly shown that stimulant treatment is of utmost importance for the management of ADHD (3). Thus, the MTA study added further evidence to the efficacy of stimulants that has been proven in large numbers of well-controlled studies. However, there is some concern that stimulants may be overprescribed in the community for children who do not meet full criteria for ADHD or even received false-positive diagnoses leading to overtreatment (4). Overprescription may represent a new major problem in addition to those insufficiently identified true ADHD cases representing the problem of undertreatment. The latter problem may be even more representative for adult ADHD patients who, because of the frequent lack of identification by knowledgeable professionals, rarely or rather only lately receive adequate treatment. Interventions with adult ADHD patients should be tailored according to the concept of multimodal treatment that is successfully dominating child and adolescent psychiatry for quite some time. Thus, in addition to stimulant treatment individual and/or group counseling, teaching of adaptive coping skills for a disorder interfering with everyday life's activities, cognitive-behavioural treatment, the inclusion of partners and families, and the support from self-help groups are the essential components of a successful intervention program with adult ADHD patients. Stimulant treatment in child and adult ADHD subjects is surprisingly similar both in terms of doses and effects. The use of the most widely administered compounds methylphenidate (MPH) and amphetamine leads to a marked improvement of attention-deficits, reduction of hyperactivity and as a secondary phenomena to a less impulsively driven psychosocial functioning in everyday life's activities. Both animal and human research supports the view that MPH acts both on the noradrenergic and the dopaminergic systems by increasing the levels of the respective neurotransmitters in the extracellular space (5). However, our understanding of the therapeutic actions of MPH is still incomplete. The recent ADHD article published in the January issue of this journal by Moll et al. (6) provides an interesting new aspect of MPH related therapeutic actions. The authors performed some sophisticated and non-invasive experiments in order to test intracortical inhibition and facilitation by using transcranial magnetic stimulation. Their findings based on healthy adult volunteers showed a significant enhancement in intracortical facilitation but no effects on intracortical inhibition under MPH administration. These effects, in contrast to some recent findings by the authors, showed enhanced intracortical inhibition in ADHD children under MPH administration. Thus, the latter mechanism may be specific to the therapeutic action of MPH in ADHD. In child and adolescent psychiatry, ADHD over decades clearly has been and remains the most intensively researched topic. The slowly increasing number of studies dealing with basic, clinical, and therapeutic aspects of adult ADHD is a promising sign indicating a greater awareness of the needs of this older clientele in order to achieve adequate assessment and intervention.