Table 4.

Taxonomy: model descriptions

Addiction consult models	Target patient population	Staffing	Core clinical activities	Systems change activities
Interprofessional addiction consult service (ACS): Provides comprehensive care for people SUD. Educates staff and trainees. Creates hospital and health system-level change.	Any substance, any readiness for change	Team-based care that, at minimum, includes (1) medical provider (addiction physician or advanced practice practitioner), (2) dedicated social worker or case manager with addictions expertise. Often includes others, including peers, navigators, nurses, pharmacists Care is typically delivered in-person, though some telehealth ACS exist. Staff may have longitudinal relationship with patients over multiple admissions and across varied stages of change. Staff have dedicated time and funding, which may include come from hospital, grants, and billing revenue.	Provide comprehensive SUD assessment and diagnosis (e.g., DSM-5, ASAM assessments) Identify and treat withdrawal (including polysubstance) Offer evidence-based treatment with medications (e.g., methadone, buprenorphine, acamprosate); provide buprenorphine at discharge Provide supported pathways to various community SUD services (e.g., opioid treatment programs, harm reduction services, residential programs). Explicit engagement efforts (e.g., peers) Emphasize trauma-informed care and harm reduction. Support complex acute medical needs (e.g., pain) Advocate for patients to receive needed care (e.g., valve replacement surgery, hepatitis treatment) Provide early comprehensive discharge planning that address social determinants of health.	Widespread hospital staff education (bedside and didactics), often addressing stigma Include trainees (e.g., fellow, resident, interdisciplinary students). Improve hospital practices (e.g., endocarditis care) and policies (e.g., active use) Lead large scale quality improvement efforts, including responding to emerging needs (e.g., COVID, changes in drug supply)
Psychiatry consult liaison service (PCL): Typically focuses on addressing SUD and co-occurring psychiatric needs. Not all offer MOUD or MAUD.	Patients with co-occurring SUD and other mental health condition.	Typically includes psychiatrist (general or addiction psychiatry) and a psychiatric social worker who is familiar with local mental health resources. Staff have dedicated time/funding; typically on site and in person. Staff typically funded by hospital and billing revenue.	Comprehensive psychiatric diagnosis (e.g., DSM-5) May offer motivational interviewing or behavioral therapies Psychiatric medication management; though some do not offer MOUD. Make recommendations for post-hospital treatment setting (e.g., detoxification, community dual diagnosis treatment); less likely than ACS to have established community partnerships and supported treatment pathways.	Rare; not explicit focus of model.
Individual consultant:	All patients, regardless of interest in changing use, substance type, or interest in a particular treatment	Addiction physician (backgrounds vary, include psychiatry, toxicology, internal medicine/family medicine) Typically funded through billing revenue, sometimes with additional grant or hospital funding. May partner with other disciplines (e.g., infectious disease consultants) to address specific disease conditions (e.g., endocarditis). Does not include a team member whose primary focus is engagement (such as peers or social workers).	Diagnose and treat SUD. Identify and treat withdrawal. Offer evidence-based medication for all SUD and provide bridge buprenorphine prescription at discharge. Sometimes partner with other disciplines to guide hospital care (e.g., multidisciplinary endocarditis management). Usually partner with general hospital staff (e.g., unit social worker) who may make treatment referrals.	May develop order sets, protocols, and general provider education materials.
Practice-based models	Target patient population	Staffing	Core clinical activities and notable features	Systems change activities
Hospital-based opioid treatment (HBOT): Primary team (e.g., hospitalist) or specialist consultant (e.g., infectious disease provider) offer medication for opioid use disorder as part of their standard practice.	Patients with OUD interested in medication treatment.	Requires general hospital providers (e.g., hospitalists, residents) or subspecialists with buprenorphine waiver. Some HBOT models have additional supports such as dedicated navigator. Staff often connected with formal and informal mentoring, warm lines, and other training/clinical supports. Typically no dedicated funding.	Offer MOUD (buprenorphine; may or may not also offer methadone, naltrexone intramuscular). Some offer naloxone kits and overdose education. Refer to post-hospital OUD treatment, including prescription for buprenorphine at discharge. Typically model does not address co-occurring pain, complex clinical decision-making (e.g. assessing appropriateness for surgery) or explicit efforts around motivational enhancement or patient engagement.	Prescribers commonly rely on buprenorphine and/or methadone protocols/order sets and policies.
Hospital-based alcohol treatment (HBAT): Primary team or specialist consultant (e.g., hepatology) offer medication for alcohol use disorder as part of standard practice.	Patients with AUD interested in medication treatment.	Care delivered by general hospital providers (e.g., hospitalists, residents) or subspecialists as part of their usual care. Example of RN-driven HBAT. Typically no dedicated funding.	Offer medication for alcohol use disorder (e.g., naltrexone, acamprosate) in hospital. Refer to post-hospital AUD treatment, typically through primary care medication based treatment and/or recommending fellowship resources (e.g., alcoholics anonymous).	May include order sets and protocols to guide care.
In-reach models	Target patient population	Staffing	Core clinical activities and notable features	Systems change activities
Community-based provider in-reach provides remote support to initiate or sustain MOUD during admission.	Patients interested in initiating MOUD or already on MOUD at time of admission	Typically, community medical providers with buprenorphine waiver (e.g., primary care or specialty addictions providers). Example of RN-based in-reach with community nurse who is connected to outpatient substance use treatment programs. Staff are not formal part of hospital care teams. Typically no dedicated funding and may be difficult for providers to bill encounters if not credentialed at hospital. Typically providers are local clinicians, though telehealth opportunity exists.	General hospital providers contact community providers who may provide brief assessment (typically by phone or video). Offer guidance to primary teams re initiation and provision of MOUD. For buprenorphine, typically offer bridge prescription and follow up appointment in their ambulatory practice at discharge. Staff typically do not document in the hospital record.	N/A; focus is direct patient contact with referral after discharge.

OUD opioid use disorder, AUD alcohol use disorder, SUD substance use disorder, MOUD medication for opioid use disorder, MAUD medication for alcohol use disorder, DSM-5 Diagnostic Specific Manual 5th edition, ASAM American Society of Addiction Medicine, RN registered nurse