Effects of Low-Intensity Behavioral Treatment for Children with Autism and Mental Retardation Sigmund Eldevik, 1,4 Svein Eikeseth, 2 Erik Jahr, 1 and Tristram Smith 3 We retrospectively compared 2 groups of children receiving either behavioral treatment (n=13) or eclectic treatment (n=15) for an average of 12 hours per week. Children were assessed on intelligence, language, adaptive functioning and maladaptive behavior at pretreatment and 2 years into treatment. The groups did not differ significantly at pretreatment. After 2 years of treatment, the behavioral group made larger gains than the eclectic group in most areas. However, gains were more modest than those reported in previous studies with children receiving more intensive behavioral treatment, and it is questionable whether they were clinically significant. KEY WORDS: Behavioral intervention; eclectic treatment; autism; intensity. A number of recent studies have shown that behavioral treatment may enhance the intellectual, language and adaptive functioning of children with autism (Anderson et al., 1987; Eikeseth, Smith, Jahr, & Eldevik, 2002; Harris & Handleman, 2000; Harris et al., 1991; Lovaas, 1987; McEachin, Smith, & Lovaas, 1993; Sheinkopf & Siegel, 1998; Smith, Eikeseth, Klevstrand, & Lovaas, 1997; Weiss, 1999). Reviewers of the literature conclude that, to achieve best possible outcome, behavioral treatment needs to be intensive (Green, 1996; Smith & Lovaas, 1998). Indeed, as much as 40 hours per week of one-to-one behavioral treatment for a minimum of two years may be required to produce optimal results. Lovaas (1987) provided 40 hours per week of one-to-one behavioral treatment for 2–3 years to a group of 19 children with autism who were less than 3 years and 10 months at intake. By the age of seven years 47% (9 children) achieved normal intellectual functioning and successful performance in school. These gains were maintained for eight of the nine children at follow-up when the children averaged 13 years of age and had been out of treatment for three to nine years (McEachin et al., 1993). Another 42% (8 children) made clinically meaningful gains, and only 11% were classified as severely or profoundly mentally retarded and placed in classes for children with autism and mental retardation. The average IQ gain for the intensively treated group was 20 points. A control group of 19 children that received 10 hours or less per week of the same treatment lost an average of five IQ points, suggesting that treatment intensity was related to outcome. In other studies where children have received somewhere between 20 and 30 hours per week of one- to-one behavioral treatment gains have been more modest showing average IQ gains between 4 and 17 points (Anderson et al., 1987; Birnbrauer & Leach, 1 Akershus University Hospital, Nordbyhagen, Norway. 2 Akershus University College and Glenne Center, Sandvika, Norway. 3 University of Rochester Medical Center, Rochester, NY, USA. 4 Correspondence should be addressed to: Sigmund Eldevik, Department for Early Intervention (STI), Nordvoll School and Autism Center, Dr. Dedichensvei 18, 0675 Oslo, Norway; e-mail: sigmund.eldevik@nordvoll.gs.oslo.no 211 0162-3257/06/0200-0211/0 Ó 2006 Springer ScienceþBusiness Media, Inc. Journal of Autism and Developmental Disorders, Vol. 36, No. 2, February 2006 (Ó 2006) DOI 10.1007/s10803-005-0058-x Published Online: February 14, 2006