Advances in Understanding Causes of Autism and Effective Interventions

Understanding the aberrant biological mechanisms that underlie autism and its spectrum disorders is an exciting challenge for researchers and clinicians because breakthroughs in our understanding of the primary causes of autism are expected to lead to new approaches for intervention, prevention or even cures. This review will highlight some recent advances in our understanding of the causes of autism and of its treatment, including: · How some forms of autism can actually be prevented · The possibly changing prevalence of autism · Problems in diagnosing autism, particularly in very young children, and how such problems can complicate the interpretation of research results · The many different types of autistic disorders and "double syndromes" that are associated with autistic features · Different biological abnormalities in autism including abnormalities of neurotransmitters, metabolism, the immune system, and brain structure and function · Suspected environmental risk factors for autism · Genetic risk factors for autism · The importance of animal models for autism · Therapeutic approaches in autism including medical, intensive early behavioural, educational, and "alternative" interventions The need for multi-disciplinary teams for clinical assessment and intervention and the plights of individuals with severe autism, especially of older children, adolescents, and adults, are stressed. Autism was first described in detail in 1943 by Leo Kanner after observing similar behaviour patterns in 11 children. He further noticed a common "extreme aloneness from the beginning of life and an anxiously obsessive desire for the preservation of sameness" (Kanner, 1943, p. 217). He referred to his children as being autistic, a term coined in 1911 by Eugen Bleuler who used it to refer to a narrowing of relationships to people and to the outside world, a narrowing so extreme that it seemed to exclude everything except the person's own self. Hans Asperger made similar discoveries at about the same time, but the patients he identified all had speech (Fombonne & Tidmarsh, 2003). Thus, the term Asperger syndrome is often applied to higher functioning people with autism who have speech (see also Frith,1989). There have been several controversies regarding the cause of autism over the years. For example, the main cause was assumed by some to be bad parenting. Today, however, there is general agreement that the symptoms of autism, with the exception of those of abandoned children, are a behavioural response by young children to an organic disease affecting their brains. In fact, it is now generally understood that autism is a complex developmental syndrome representing a heterogeneous group of disorders with similar symptoms, but with different biological etiologies. Realizing that autism does not have a single cause has been important for enhancing the understanding of its etiologies, prevention and treatment. There have been many significant advances in scientific research with respect to understanding the multi-causal nature of autism. One of the most encouraging developments is that some forms of autism appear to have causes that can be prevented. There is evidence, for example, that autism is strongly associated with congenital rubella infection (Chess, 1977; Trottier, Srivastava & Walter, 1999). Since young women can now be immunized against rubella before they become pregnant, such immunization should prevent "rubella autism. " Another example of a preventable cause of autism is phenylketonuria (PKU), a disorder associated with features of autism in which the amino acid phenylalanine cannot be properly metabolized (Lowe, Tanaka, Seashore, Young & Cohen, 1980). Fortunately, PKU is now largely a disorder of the past, at least in developed countries. Infant screening programs can now detect PKU during the neonatal period and early childhood. With very early diagnosis, PKU can be controlled by therapeutic diet, which ensures a low intake of phenylalanine in order to prevent further development of the disorder. Thus, there now is growing evidence that many factors genetic, environmental, metabolic and immunological are involved in autism. Identifying the primary factors that result in autism is important because such knowledge will lead to better treatments, prevention, or even cures. In this paper, we review recent research advances in the field of autism, including searches for primary causes and for effective forms of intervention.