Reese, Thomas J and Tindle, Hilary A and Bachmann, Justin and Wright, Adam and Ancker, Jessica S and Audet, Carolyn M and Shah, Mauli V and Steitz, Bryan D and Levin, Michael H and Kast, Kristopher A and Marcovitz, David and von Horn, Amanda and Kelley, A Taylor and Bridges, John F P (2026) Patient-reported outcomes for monitoring substance use treatment: a systematic review of single-item measures. Addiction , Early online .