Intensive Behavioural Intervention has been in use since the mid-1980s. Applied behaviour analysis, from which it is derived, has its roots in behaviour therapy developed in 20th century.
Dr. O. Ivar Lovaas worked with non-verbal, institutionalised children with autism in the late 1960s and early 1970s in the USA. He concentrated on improving verbal skills using applied behaviour analysis.
Unfortunately most of the children lost their verbal skills when the programme ceased and they returned to institutional life. However those who moved back with their parents did much better.
Lovaas went on to work with younger children, aged 2 to 4, in their home setting to see if the skills learned by the children were maintained. He developed Early Intensive Behavioural Intervention (The Lovaas Method) from this work.