Providers Clinical Support System (PCSS) Providers Clinical Support System (PCSS) is a national training and clinical mentoring project developed in response to the prescription opioid misuse epidemic and the availability of pharmacotherapies to treat opioid use disorder. PCSS trains health professionals to provide effective, evidence-based, medication-assisted treatments to patients with opioid use disorder in primary care, psychiatric care, substance use disorder treatment, and pain management settings. Providers Clinical Support System website.