Toward an adequate understanding of attention deficit disorders

Abstract

Toward an adequate understanding of attention deficit disorders Rumo à compreensão adequada das doenças do déficit de atenção Throughout the world, the syndrome identified in DSM-IV as Attention Deficit/Hyperactivity Disorder (ADD) is being increasingly diagnosed in children, adolescents and adults, most of whom find treatment quite helpful. Yet many clinicians and others remain skeptical about the validity of this diagnosis, particularly in adults. For some, this skepticism rests upon an overly simplistic understanding of the ADD syndrome; they assume that this is simply a childhood behavior disorder that persists in some adults who remain hyperactive. Barkley & Murphy recently published data showing that adults with ADD are distinguished from community or clinical controls not by hyperactivity, but by a variety of impairments in executive functions. 1 Although there are conflicting views of how best to describe the relationship of executive functions to ADD, data from multiple sources indicate that ADD is essentially a complex syndrome of impairments in development of the brain's selfmanagement systems. 2 Key elements of this emerging model include: 1) ADD is essentially a complex disorder in the unfolding development of the brain's executive functions, its management systems. Although early decades of research on ADD were concerned with disruptive behavior, recent years have brought increasing emphasis upon cognitive impairments involved in this disorder. These include chronic problems with focusing attention on tasks, utilizing working memory, organizing work, getting started on tasks, and sustaining effort to complete them in a timely way, etc. These cognitive functions might be compared to the work of the conductor of a symphony orchestra who selects what is to be played, directs each musician to play his or her specific part in the same piece at the same, signals the moment to bring in one section and fade out another, and generally oversees and manages the overall performance. Persons with ADD tend to have chronic impairments in their ability to perform a wide range of complex self-management functions that are essential to age-appropriate performance in school, family life, employment and social relationships. 3 2) ADD symptoms may be noticeable during early childhood, but often are not apparent until the individual encounters challenges of adolescence or adulthood. Networks that support the brain's executive functions develop slowly, from early childhood until well into the early twenties. Many are localized in the prefrontal cortex, but they operate in conjunction with neural circuits in the limbic region and cerebellum. These complex circuits do not reach full maturity until late adolescence or early adulthood. Some cases of ADD impairment are apparent in preschool years, for example, the child who is kicked out of daycare because of inability to meet minimal demands for self-regulation: keeping hands to self, complying with instructions, listening to the adults.