This article is a great read., and links to the BBC news item this morning about a research project exploring if parents with children with autism are experiencing stress.

Some children on the spectrum may exhibit problematic behaviors when asked to change their routine or to transition from one task, activity, or setting to another. Why is this?
— Read on www.findatopdoc.com/Parenting/Why-Do-Kids-on-the-Spectrum-Have-Trouble-with-Transitions