Attention Deficit Hyperactivity Disorder has recently found a place in two current diagnostic manuals: the American DSM IV and the European ICD 10. These manuals seem to be moving towards 'greater harmony' in their definition of 'the bahaviours that are considered to be the basis for the diagnosis' (Taylor, 1994 : 228).

In 1991 Eric Taylor, a leading authority in the study and research of ADHD in this Country, was already advocating the need for a clinical distinction of the froup of children characterised by the presence of activity and attention deficit from the group with anti-social conduct and hyperactivity. He also distinguished between the children with Hrperkenisis caused by structural damage of the brain or by psycho-social problems.

Co-Morbidity is common: many symptoms found in ADHD are also present in other conditions and this may explain why ADHD is over-diagnosed. 'The nature of the supposed in hyperactivity is unknown' wrote Taylor and. 'Cooespndingly, the definition of hyperactivity and the frequency with which it is applied vary between clinicains' (1991 : 8).

In 1994, despite the rapid growth of investigation, research and more explicit diagnostic criteria, 'cultural differences remain.........and the history of thinking about these behaviours still shackles the range of therapeutic efforts in the present' (Taylor, 1994 : 285). In 1996 Steifel wrote that ADHD 'is still a controversial disorder in regard to prevalence, aetiology, conceptualisation, diagnosis and treatment' (Stiefel, 1996 : 3). I n 1999 considerable diversity betweenn parctioners still exist even in the USA, as the National Institute of Health Consensus Development Statement (1998) portrays.

Taylor (1994) and Rutter (1982) diferentiated 'situational' ADHD which can occur at home but not at school and vice versa, from the 'pervasive' ADHD which requires the behaviour to be observable in at least three major situations in the child's life.