Etiologic classification of attention-deficit/hyperactivity disorder.
ABSTRACT Attention-deficit/hyperactivity disorder is a neurobiological syndrome with an estimated prevalence among children and adolescents of 5%. It is a highly heritable disorder, but acquired factors in etiology are sometimes uncovered that may be amenable to preventive measures or specific therapy. Early reports have described symptoms similar to attention-deficit/hyperactivity disorder that followed brain trauma or viral encephalitis, and recent MRI studies have demonstrated brain volumetric changes that may be involved in the pathophysiology of the syndrome. The American Psychiatric Association's Diagnostic Statistical Manual, introduced in 1968, emphasizes symptomatic criteria in diagnosis. Here, an overview of environmental factors in the etiology of attention-deficit/hyperactivity disorder is presented to encourage more emphasis and research on organic causal factors, preventive intervention, and specific therapies. An organic theory and the genetic and biochemical basis of attention-deficit/hyperactivity disorder are briefly reviewed, and an etiologic classification is suggested. Environmental factors are prenatal, perinatal, and postnatal in origin. Pregnancy- and birth-related risk factors include maternal smoking and alcohol ingestion, prematurity, hypoxic-ischemic encephalopathy, and thyroid deficiency. Childhood illnesses associated with attention-deficit/hyperactivity disorder include virus infections, meningitis, encephalitis, head injury, epilepsy, toxins, and drugs. More controversial factors discussed are diet-related sensitivities and iron deficiency. Early prenatal recognition, prevention, and treatment of environmental etiologies of attention-deficit/hyperactivity disorder may reduce physician reliance on symptomatic modification with medication, a frequent reason for parental concern.
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ABSTRACT: Executive functions (EFs) include a number of higher-level cognitive control abilities, such as cognitive flexibility, inhibition, and working memory, which are instrumental in supporting action control and the flexible adaptation changing environments. These control functions are supported by the prefrontal cortex and therefore develop rapidly across childhood and mature well into late adolescence. Given that executive control is a strong predictor for various life outcomes, such as academic achievement, socioeconomic status, and physical health, numerous training interventions have been designed to improve executive functioning across the lifespan, many of them targeting children and adolescents. Despite the increasing popularity of these trainings, their results are neither robust nor consistent, and the transferability of training-induced performance improvements to untrained tasks seems to be limited. In this review, we provide a selective overview of the developmental literature on process-based cognitive interventions by discussing (1) the concept and the development of EFs and their neural underpinnings, (2) the effects of different types of executive control training in normally developing children and adolescents, (3) individual differences in training-related performance gains as well as (4) the potential of cognitive training interventions for the application in clinical and educational contexts. Based on recent findings, we consider how transfer of process-based executive control trainings may be supported and how interventions may be tailored to the needs of specific age groups or populations.Frontiers in Psychology 05/2014; 5:390. · 2.80 Impact Factor
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ABSTRACT: In recent years, there is an increasing awareness that individuals may purposely feign or exaggerate symptoms of attention deficit hyperactivity disorder (ADHD) to gain external incentives, including access to stimulant drugs or special academic accommodations. There are vast consequences of undetected feigned ADHD such as substantial costs covered by society for unnecessary assessments and treatments, unjustified occupation of limited medical resources and undermining society's trust in the existence of the disorder or the effectiveness of treatment. In times of economic crisis and cost savings in the medical sector, the detection of feigned ADHD is of importance. This review briefly describes the research on this topic with an emphasis on the approaches available for detection of feigned ADHD (i.e., self-report questionnaires, personality inventories, cognitive tests used in routine neuropsychological assessment and tests specifically designed for detecting feigned cognitive dysfunction). Promising approaches and measures are available for identifying feigned ADHD but there is an immediate need for further research.Journal of Neural Transmission 08/2014; · 2.87 Impact Factor
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ABSTRACT: Examine the hospital admission risk in young children who are subsequently diagnosed with attention deficit hyperactivity disorder (ADHD). We conducted a population-based, record linkage study. Records of all non-Aboriginal children under 18 years who met the DSMIV/ICD10 criteria for ADHD and prescribed stimulant medication in Western Australia between 2003 and 2007 (n = 11,902) were linked to two other health data systems-the hospital morbidity data system and the midwives notification system (MNS). The non-ADHD reference population (n = 27,304) was randomly selected from the MNS. Compared with controls, children under 4 years who subsequently were diagnosed and treated for ADHD were 70 % [odds ratio (OR) 1.70; 95 % confidence intervals (CI) 1.62-1.77] more likely to be admitted to hospital under 4 years of age. There was an increased risk for injury or poison (OR 1.73; 95 % CI 1.59-1.88), respiratory disease (OR 1.49; 95 % CI 1.40-1.59), ear disease (OR 2.03; 95 % CI 1.86-2.21), infectious diseases (OR 1.68; 95 % CI 1.53-1.85) and neurological conditions (OR 2.03; 95 % CI 1.68-2.44). Admissions under 4 years of age for head injuries, burns, poisons, all other injuries, diseases of the tonsils and adenoids, asthma and early infections were all more common amongst children subsequently diagnosed with and treated for ADHD. There is significant early hospital morbidity for children subsequently diagnosed with ADHD. Multiple aetiologies and causal pathways need to be considered where some of these may include early infections, inflammatory conditions, epilepsy and injuries. Future studies should look at which of these conditions may be on the causal pathway or likely early markers for ADHD.European Child & Adolescent Psychiatry 04/2014; · 3.70 Impact Factor