Frequently, people will refer to this issue with the term “obsession”, but I don’t like to use obsession in this case. Technically, “obsession” as used in the mental health sense refers to stuck images, thoughts or ideas that are a part of Obsessive Compulsive Disorder. Although some individuals with ASDs also have OCD, that’s not always the case.The content of thoughts in OCD also tend to be different than those found with ASDs. (For an excellent article on this, see McDougle, C. J., Kresch, L. E., Goodman, W. K., et al (1995) A case-controlled study of repetitive thoughts and behaviour in adults with autistic disorder and obsessive-compulsive disorder. American Journal of Psychiatry, 152, 772 -777)
An excellent book for self treatment of OCD is Brain Lock: Free Yourself from Obsessive Compulsive Disorder, by Jeffrey M. Schwartz, M. D. Schwartz presents a four step program involving learning to recognize obsessive thoughts, labelling them as a part of OCD, focusing on something else for at least a brief while, and then finally “revaluing” these obsessive thoughts. You can find a clear explanation of these four steps on the website for the Westwood Institute for Anxiety Disorders, Inc.
Neither the book nor the website talk specifically about the autism spectrum and repetitive thoughts, but Brain Lock does have an interesting chapter on the Four Steps and Other Disorders, and states that they can be applied to “almost any behavior you genuinely want to change.” (p. 187) The ideas in this book are certainly worth considering for those on the autism spectrum dealing with this troublesome issue.