It has done studies that show that certain diseases, like attention deficit disorder in children, are treated very differently depending on where the patient lives.

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The advice also stresses the need to make sure that children take medicine for conditions such as attention deficit hyperactivity disorder or for behavioural problems on the trip.

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Work by other researchers, however, has suggested such supplements do improve the performance and behaviour of school-age children with specific diagnoses such as dyslexia, attention-deficit disorder and developmental co-ordination disorder.

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One of the children they placed was a ten-year-old boy with attention deficit disorder and hyperactivity.

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Many are concerned that Ritalin and similar drugs, which aid concentration in those with Attention Deficit Hyperactivity Disorder, are chemical straightjackets that prevent children from taking full responsibility for themselves.

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