**Appendix: Search Strategy**

To identify relevant studies, the authors used the same search terms as two previously published systematic reviews of psychotherapy for T2DM [4, 5]. The search was conducted by pairing relevant search terms, including "psychotherapy", "cognitive-behavioral therapy", "motivational interviewing", "counseling", "supportive therapy", and "mindfulness-based therapy", with "type 2 diabetes" and "randomized controlled trial" on PsycINFO, PubMed, and Medline using a Boolean "AND". The search was limited to articles published after December 2012 since this was the end of the period reviewed since the last review paper [5]. The original search was conducted on January 24th, 2019, then repeated at each revision, on March 24th, 2019, October 28th, 2019, and November 12th, 2020, to be thorough. The initial search identified 268 articles. After duplicates across search engines were removed, articles were screened by the primary author based on titles and abstracts. For the screening process, full articles were retrieved and reviewed to confirm relevance and eligibility. The primary author extracted data on intervention type, methods, and outcomes. To be included in this review, the article must have been an RCT that examined a psychotherapeutic intervention for participants who met criteria for T2DM at the time of recruitment and must have changes in HbA1c levels as a health outcome. Only RCT's were reviewed so as to include only the most scientifically rigorous research on this topic. Studies that used only pharmacological interventions were not included. In addition, interventions that specifically targeted comorbid disorders (e.g., depression in individuals with T2DM) and studies that were not reported in English were also excluded from this review. In the end, 16 articles remained and were reviewed.
