[Current status of autism studies].

The current status of autism studies was reviewed based on English articles published during the 1990s. Although the concepts of autism and pervasive developmental disorders (PDD) are established, diagnostic criteria of PDDNOS or atypical autism, which is frequently difficult to differentiate from autism, need to be established. The prevalence of autism has been estimated as about 0.05% in the U.S and many European countries, while it was reported to be 0.1% or higher in Japan and some European countries, though the reasons for this difference are unclear. High-functioning (IQ > or = 70) autism may not be as rare a condition as previously thought and both its difference from and similarity to Asperger's syndrome, the highest functioning PDD subtype, need clarification. About 20 to 40% of children with autism lose meaningful words by the age of 2 years and display autistic symptoms thereafter. Such autism, called the setback type in Japan, has been demonstrated to have a poorer adolescent/adult outcome compared to autism without setback and its relationship with childhood disintegrative disorder, which displays a clearer regression after normal development for at least the first 2 years of life, needs to be addressed. The etiology of autism is now considered mostly genetic for reasons, such as the significantly higher concordance rate of autism in identical twin pairs (60-80%) than in fraternal twin pairs (0-10%) and an 3-5% incidence of autism among sibs of an autism proband, 30 to 100 times higher than that in the general population. The involvement of several genes is implicated to create susceptibility for autism, yet the responsible genes have not been identified. Although there is no medication to cure autism, some psychotropic drugs, such as antipsychotics and SSRIs, seem effective for behavior problems in autism patients. Psychosocial treatments are the main therapeutic approach to autism, though they are yet to be well systematized. It is important to evaluate various autism treatments now practiced and to integrate effective ones into an efficient therapeutic system. Early diagnosis of PDD, support for the mother to develop a better relationship with her autistic infant, enrollment of an autistic infant in a day care for handicapped or non-handicapped infants, education in a relevant school, vocational training, treatment of behavior problems, and establishing social welfare services are a framework of the therapeutic system of autism. Much should be done to improve the long-term outcome of autism patients, including high-functioning autism.