There are a large number of theoretical explanations of the development of behaviour disorders, which come under the broad headings of biophysical, psychodynamic, behavioural, cognitive-behavioural, sociological, and ecological. Each of these points of view covers a variety of theories that are different in a number of ways. They range from the disability perspective (examining causes within the individual), to the deviance perspective (examining external conditions which cause children to deviate from "normal" behaviour), to the alienation perspective (examining external social forces that distort the emotional development of otherwise healthy people) (Newcomer, 1993, p.27-28). Each of the theoretical standpoints will be discussed in order, with emphasis on its educational implications, and evaluation of its usefulness to special education.
             The biophysical point of view asserts that behavioural disorders are the result of an underlying physical disturbance or disorder (Rosenberg et al, 2004, p.8), and ignores external forces. Biological theories maintain that a pathological condition exists because of deficiencies of the individual (Newcomer, 1993, p.27). Genetic transmission is one major biophysical theory. Genetic transmission theories have been put forward to explain the cause of autism, schizophrenia, hyperactivity, aggression and rule breaking (Rosenberg et al, 2004, p.10).
             Brain injury and neurological dysfunction, another facet of the biophysical model, explains stronger cases of severe behaviour problems (autism, early onset schizophrenia) more than common learning problems such as hyperactivity and impulsivity.
             Biochemical abnormalities also are widely believed to cause disordered behaviour, however there is little agreement as to which processes, when disrupted, actually cause the behaviour problem (Rosenberg et al, 2004, p.11). For example, pervasive developmental disorders (PDD) may be related to the ov...