The severity level of autism determines the duration of ABA therapy. Generally, the treatment regimen lasts from one to three years, depending on the age and diagnosis of the child. For a child over three, 30 to 40 hours of intervention per week are recommended, while for a child under three, 26 to 30 hours per week are suggested. Comprehensive ABA treatment usually consists of 26 to 40 hours of individual direct therapy each week and is recommended when a child shows deficits in most developmental domains.
Early intervention for autism is the best and can begin as early as 18 months, with 25 to 40 hours per week on therapy sessions. After diagnosis, parents may be forced to wait considerable time to move forward in the process and receive evidence of their child's ability to learn. Treatment intensity and duration alone account for a large percentage of the variance found in the domain of learning objectives within each domain. Both treatment intensity and duration of treatment predict mastery of learning objectives, with the highest percentages of variance in response to treatment found in the motor and adaptive domains.
Increasing the intensity of treatment has significant positive effects on progress and improvement of skill, but the effect of the duration of treatment requires further study. Treatment-specific variables such as professional or teacher training, treatment location and clinical supervision have also been investigated.
