Unfortunately, I am unable to create an abstract for the article titled "No Added Benefit for Collaborative Care in Patients With OUD and Mental Illness" because this article is not included in the provided search results. The resources provided include information on "The Whole Health Study" which in turn tests collaborative care models for patients with opioid use disorder and mental illness, but the results of the article you requested to summarize are not included. In order for me to produce an accurate and factual summary per your request, I would need access to the full text of the specific MedPage Today article.