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Journal Article 2005; 26(4): 423-430 PubMed PMID: 16135997 Citation  Keywords:  Attention Deficit Disorder with Hyperactivity:genetics, Biomarkers, Brain Chemistry:genetics, Genetic Markers, Humans,.   

: ADHD (attention hyperactivity disorder) is a polygenetic disorder with various candidate genes. At this time, more than thirty dopaminergic, noradrenergic, serotonergic and GABA-ergic genes are known. The research of only some candidate genes (DRD4, DAT, DRD5, DBH, 5HTT, HTR1B and SNAP25) brought relatively consistent results confirming the heredity of ADHD syndromes. The results of research of other genes (DRD2, DRD3, MAO, ADR2A, GABA A3, GABA B3) are not clear yet. This paper summarizes the most important genetic data in correlations with biochemical periphery parameters (especially for DBH, HVA, MHPG, serotonin). Hypothetically, certain subgroups of ADHD may be identified by correlation of biochemical characteristics and some candidate genes. The paper discusses some implications for future research. Review....

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Journal Article 2003; 24(3-4): 151-160 PubMed PMID: 14523349 Citation  Keywords:  Aging:physiology, Attention:physiology, Brain:growth & development, Consciousness Disorders:psychology, Electroencephalography, Electrophysiology, Eye Movements:physiology, Female, Gravitation, Humans, Learning:physiology, Male, Sleep:physiology,.   

: The interest in studying the brain electrical activity as a function of the development of intelligence has been spurred by the need to understand how the brain responds to environmental information. The description of sleep in mentally retarded children reveals deviant patterns of the EEG-spindles and of the eye movement activity (REM sleep) when compared to normal children. The patterns may be considered as a valuable index of mental function. According to experimental evidence, the distribution of the eye movements of sleep appears either as random or ordered. The latter are altered in the mentally handicapped in whom the appearance out of chaos, of the order which is needed for intelligence and memory to function, is altered. The sleep signs are redundant as from birth. Their pattern is also related to the psychomotor development of the infant. If their distribution remains random, or appears in long uninterrupted sequences of waves as in epilepsy, intelligence does not develop. A similar strategy appears to function in the foetus when nature organizes the structures that will lead to the development of intelligence. The eye movement patterns of sleep change in the pregnant women as a function of term and resemble those of premature babies of a similar gestational age. They also change as a function of the menstrual cycle and more generally as a function of age. The hypothesis that attention is the diurnal equivalent of REM sleep is discussed. Attempts at modelling the eye movement patterns of REM sleep as a function of near zero gravity environments have been made. 1) By means of a Montecarlo simulation using the semi Markov model during the Spacelab 1 flight. 2) With the method of the single and multiple g-phase transition analysis of the strange attractor dimension (d) during parabolic flights. The implication of the latter for the neural processes involved in learning is that the central nervous system can preserve intact, from input to output, over a period of several days, all the information it receives 3) The relation between spindles and eye movements has also been viewed by a quantum approach which is another medium between the information and the way of describing it....

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Comment 2003; 24(3-4): 148-150 PubMed PMID: 14523348 Citation  Keywords:  Adaptation, Psychological:physiology, Attention Deficit Disorder with Hyperactivity:diagnosis, Biological Evolution, Child, Child Behavior:physiology, Humans,.   

: The evolutionary approach to the issue of ADHD derives from the assumption that what is regarded as a pathological phenomenon today was once an adaptive response to the conditions of life in the ancestral stages of human development. The paper argues against this conception on the basis of the clinical picture of ADHD. The author believes that in the previous "natural" conditions the ADHD syndrome was even more of a maladaptation than in the "protective" conditions of present-day life....

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Journal Article 2002; 23(1): 45-48 PubMed PMID: 11880861 Citation  Keywords:  Attention Deficit Disorder with Hyperactivity:drug therapy, Attention Deficit and Disruptive Behavior Disorders:metabolism, Central Nervous System Stimulants:therapeutic use, Child, Dextroamphetamine:therapeutic use, Female, Humans, Hydrocortisone:metabol.   

OBJECTIVES: There is growing interest in the role of the hypothalamic-pituitary-adrenal (HPA) axis in neuropsychiatric disorders and there is some evidence that the HPA axis may be underfunctional in behaviorally disturbed children. However, co-morbidity is common in childhood neuropsychiatric disorders. Stimulant medication is widely used in the treatment of Attention-deficit hyperactivity disorder (ADHD) and can increase cortisol secretion when given acutely. We therefore set out to determine the whether salivary cortisol would be reduced in a group of children with ADHD/ODD (Oppositional-defiant disorder) and to examine the effect of stimulant medication on any such relationship.

DESIGN: Salivary cortisol was determined in thirty-two children with co-morbid ADHD and Oppositional-defiant disorder (ODD) according to DSM-IV criteria, compared to twenty-five healthy controls of similar age and ethnic background. Data were analysed according to prescription of stimulant medication in the patient group.

RESULTS: Salivary cortisol was significantly lower in the ADHD/ODD group than in the controls. Further analysis revealed that this reduction was restricted to the subgroup of patients not prescribed stimulant medication.

CONCLUSIONS: The results support the possibility of a dysfunction of control of the HPA axis in these behaviorally disturbed children. A reduction in salivary cortisol could reflect underarousal, an elevated threshold for detection of stressors or a subsensitivity of the HPA axis itself. It remains to be determined whether the ability of stimulant medications to negate the apparent deficit in cortisol secretion in these ADHD/ODD patients is an unrelated consequence of increased dopamine release or a reflection of their therapeutic benefit. The use of stimulant medication for co-existing ADHD should be taken into account in future studies of cortisol in behaviorally disturbed children....

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