APPENDIX A. Barriers to Change Within the Treatment System and Strategies to Address Them.

Evidence Illustrating Barriers	Evidence for Proposed Strategy
Provider Barriers
1. Many clinicians, pharmacists, and support staff have stigmatizing attitudes toward patients with opioid use disorder and toward medications for opioid use disorder. Stigma is associated with greater support for punitive policies, denial of services, and reluctance to engage in treatment [12,13,14]. Clinicians display stigma against patients with SUD [15,16,17,18,19,21,53,99,125,126,127,128,129,130,131,132,133,134]. Clinicians have a lack of knowledge about MOUD efficacy and fear that prescribing MOUD will result in diversion [21,22,23,24,25,125,130,135,136,137]. Negative attitudes among clinicians can limit their willingness to treat those with SUD [26,27].	1. The Centers for Disease Control and Prevention should partner with professional associations and others to develop and implement an evidence-based stigma reduction campaign targeting clinicians, pharmacists, and support staff. Targeted education early in clinical training decreases stigma and discrimination [31]. Highlighting the efficacy of MOUD and relaying personal stories of people who use drugs decreases stigma in the general population [31,32]. Using nonstigmatizing language can improve outcomes for people with SUD [133]. Academic detailing has been used effectively to train clinicians in evidence-based opioid prescribing and naloxone distribution [1].
2. Many clinicians have insufficient training to provide evidence-based care for patients with opioid use disorder. Clinicians report being unprepared to screen, diagnose, refer, manage, or treat patients with SUD [16,20]. Training standards and practices in SUD are inadequate for clinicians—including psychiatrists [33,34,40]—and allied team members [5]. Clinicians receive inadequate training in SUD detection and the frequent co-occurrence of SUD with mental health disorders [15,17,99,128,136]. Clinicians are insufficiently trained on diagnosis and office-based treatment of OUD [66,99,128,130,138]. Clinicians are insufficiently trained in pain management [139,140].	2. Accreditation agencies should require that clinicians receive training in screening, diagnosis, and treatment of opioid addiction. These requirements should cover medical students, residents, physicians, and advanced practice clinicians (e.g., nurse practitioners and physician assistants). Recommended credentialing agencies include the Liaison Committee on Medical Education, Accreditation Council for Graduate Medical Education, Commission on Collegiate Nursing Education, Accreditation Commission for Education in Nursing, and Accreditation Review Commission on Education for the Physician Assistant. Early training in treating those with OUD is associated with greater willingness and confidence to provide OUD treatment in later practice [35,36]. Requiring training in SUD screening is a key component of a recent 2019 USPSTF recommendation [37]. It is important to provide free, easy-to-access OUD treatment and MOUD management education for trainees and clinicians [16,17,99].
3. There were insufficient numbers of addiction treatment specialists at the time of this manuscript’s publication in 2020. At the time of this paper’s publication, there were inadequate numbers of Mental health and addiction medicine professionals [20,41], Psychiatrists with specialized training in addiction [44,45,46,67,141,142], Behavioral health counselors [17,66,67,143], and Advanced practice clinicians certified to provide MOUD [47].	3A. Congress should increase opportunities to train addiction psychiatrists and addiction medicine specialists by appropriating funding for the Mental and Substance Use Disorders Workforce Training Demonstration Program, which was authorized under the 21st Century Cures Act.
	3B. Congress should increase funding for loan repayment programs for addiction specialists who treat substance use disorders in underserved areas. Loan repayment programs have long been used as strategies to recruit health professionals to rural and medically underserved areas [48].
Institutional Barriers
4. The provision of medications for opioid use disorder is often not standardized within medical and psychiatric care. A minority of patients receiving treatment for OUD receive MOUD [49,50,51]. SUD treatment facilities do not provide adequate access to MOUD [9]. Many clinical settings are inadequately prepared to prescribe MOUD to patients, despite evidence showing success in delivering this treatment in primary care practices [16,52], emergency departments [24,57], and detention centers [58,59,60,61]. There many gaps in the continuum of care, including inadequate transitions from rescue to treatment [62,63], arbitrarily short periods of medication utilization [64,65,], and poor care coordination [17,125].	4A. The National Institutes of Health and the Agency for Healthcare Research and Quality should support standards and metrics for primary care, community health centers, certified community behavioral health clinics, emergency departments, detention facilities, and mental health programs to screen for and treat opioid use disorder. Standards and metrics can be derived from primary care MOUD integration models such as the Massachusetts Collaborative Care Model [72,144]. It has been shown that emergency department initiation of treatment increases treatment engagement and decreases mortality; this should be adopted as standard practice [56]. Both government and private sector resources should be increased to expand access to treatment [141].
	4B. Agencies or organizations responsible for the accreditation and licensing of substance use treatment facilities, including the Joint Commission and the Commission on Accreditation of Rehabilitation Facilities, should ensure that providing access to effective medications is a condition of accreditation and licensure for treatment of opioid use disorder.
	4C. The Substance Abuse and Mental Health Services Administration, National Institute on Drug Abuse, and the Centers for Medicare & Medicaid Services should evaluate programs receiving federal funding to support service provision. These agencies should phase out funding for addiction treatment programs that do not offer evidence-based care, including medications to treat opioid use disorder. Reducing low-value or no-value care preserves resources that will be more effective at saving lives and promoting recovery [68].
	4D. States should organize and fund evidence-based technical assistance for clinicians prescribing buprenorphine and naltrexone, linking them to specialists and other resources. Technical assistance can increase the confidence of nonspecialist clinicians to offer addiction care [67]. State-specific guidance exists on the provision of office-based MOUD and should be shared broadly to allow for greater adoption [145].
5. There is inadequate attention to developing systems of care that are centered around patient needs. There is inadequate institutional, clinical, and peer support for people with OUD [15,17,67,70,126] including allied health professionals who can help patients manage aspects of their health care needs [71,72] and peer recovery specialists that increase patient retention in ongoing treatment [73,74]. Comprehensive care services should be implemented more broadly, as they are shown to support patients and increase clinician willingness to provide treatment [66,67,75]. Patients report many challenges when seeking care, such as not knowing where to seek care [2], long travel distances to treatment facilities, and difficulty finding child care and transportation [76]. There are significant racial disparities in ability to access MOUD [78,79] and overdose mortality [80]. There are significant geographic disparities in access to MOUD [52,53,54,55,99,135,142,147,148,149].	5A. States should implement and fund models that address patient needs at varying levels of complexity. After ensuring that these initiatives address the needs of local communities, expand models such as hub-and-spoke and telemedicine that meet the needs of diverse patient populations at varying levels of complexity [72,84,146].
	5B. The Substance Abuse and Mental Health Services Administration, National Institute on Drug Abuse, and the Centers for Medicare & Medicaid Services should implement and evaluate programs that expedite access to medications for opioid use disorder. Explore and pilot other methods to lower the threshold to accessing treatment, including providing treatment in more convenient locations (e.g., mobile clinics and shelters) or eliminating requirements such as attending group therapy or observed initiation, because removing these barriers has demonstrated greater patient engagement [76,89,90,91].
	5C. The Substance Abuse and Mental Health Services Administration, National Institute on Drug Abuse, and the Centers for Medicare & Medicaid Services should fund and evaluate innovative models of treatment delivery that address social determinants of health and racial and geographic disparities in access to care.
Regulatory Barriers
6. Laws and regulations currently limit access to treatment for addiction. Federal law requires prescribers to obtain additional training and a waiver to prescribe buprenorphine, which reduces an individual provider’s ability to prescribe buprenorphine, an FDA-approved MOUD. Federal law prevents physicians outside of opioid treatment programs to prescribe methadone, limiting an individual provider’s ability to prescribe methadone, an FDA-approved MOUD. Some state laws limit access to MOUD by imposing additional restrictions not rooted in evidence (e.g., required counseling and mental health services) [10,98]. State restrictions limit the numbers of nurse practitioners and physician assistants who can seek and use the buprenorphine waiver, further reducing those in a community who can prescribe buprenorphine, an FDA-approved MOUD [94]. Payer policies limit access to MOUD through insurance prior authorization regulations [23,66,99,100], nonevidence-based limitations on medication duration and dosages, or the required failure of other modalities before MOUD prescribing can begin [101]. DEA surveillance serves as a significant deterrent to many prescribers pursuing a buprenorphine prescribing waiver, and MOUD prescribing more generally [16,17,21,130,141,150].	6A. Once there is an assurance of appropriate training for all prescribing clinicians, Congress should repeal the requirement to obtain a waiver to prescribe buprenorphine. Eliminate buprenorphine waiver requirements for those licensed to prescribe controlled substances [17].
	6B. States should consider expanding the training and scope of practice for nurse practitioners in order to facilitate greater access to medications for opioid use disorder. Greater state practice restrictions for nurse practitioners (e.g., requiring physician oversight) were associated with a lower percentage of nurse practitioners obtaining buprenorphine prescribing waivers [94].
	6C. The Drug Enforcement Administration and Substance Abuse and Mental Health Services Administration should encourage innovation on methadone delivery. In other countries, such as Australia, Great Britain, and Canada, methadone is routinely prescribed in office-based settings and can be filled in community pharmacies [96]. Pilot studies in the United States demonstrated that delivering methadone in a primary care setting is feasible and effective [97].
	6D. Congress should preempt state laws that add unnecessary additional barriers to the provision of medications for opioid use disorder. Remove counseling requirements for access to MOUD and increase access to counseling through increased funding and reimbursement for counselors [5].
	6E. Public and private payers should eliminate utilization policies that limit access to quality treatment.
7. Restrictions on data sharing currently impede quality care. The 45 CFR part 2 privacy provision prohibits federally funded programs from sharing information around SUD without patient consent, which increases barriers to care coordination among clinicians [2]. PDMPs are a commonly used state strategy to combat excessive opioid prescribing through data sharing. However, it is unclear that they have a beneficial impact on opioid prescribing, opioid misuse and diversion, and opioid-related mortality [102,103,104]. This may in part be a result of varying utilization and usability of PDMPs in different states [106,151,152,153,154].	7A. To improve care coordination among clinicians, the Substance Abuse and Mental Health Services Administration should revise restrictions on data sharing specific to substance use treatment programs.
	7B. The National Institute on Drug Abuse should fund research exploring the impact of prescription drug monitoring programs and other data sharing tools on overdose mortality and other opioid-related health outcomes.
Financial Barriers
8. Financial barriers still prohibit access to care for many patients. Inability to afford care is often cited as a reason to not seek treatment that otherwise would be sought [2]. A particularly underinsured and undertreated population are those in jails and prisons [5,131] due to federal laws that prohibit use of Medicaid funds during incarceration [112]. Public and private payers do not currently cover MOUD prescriptions adequately [113,114,115]. There is generally inadequate reimbursement for prescribing MOUD and for clinicians treating OUD and SUD [17,23,66,99,114].	8A. All states should expand Medicaid to childless adults to gain the benefits of health coverage. State Medicaid expansions under ACA resulted in significant increases in SUD treatment utilization [109,116,117,118,119] and lower rate of opioid overdose deaths [120].
	8B. Congress should permit Medicaid funds to be used for medications for opioid use disorder for incarcerated individuals. Use of MOUD significantly reduces the risk of mortality both during and after incarceration [110,111].
	8C. States should ensure that incarcerated individuals have active health coverage immediately upon release. The vast majority of people released from prison are uninsured, and nearly all of them are eligible for Medicaid in expansion states [121].
	8D. Public and private payers should provide coverage that facilitates access to all three FDA-approved medications for opioid use disorder. Require coverage of evidence-based MOUD as an essential health benefit [17]. Increase the insurance reimbursement for providing behavioral health care [99]. Provide insurance coverage incentives for providing mental and behavioral health services [99].
	8E: States should enforce mental health parity laws [17,114].
Other Barriers
9. There is inadequate attention to the reasons why many people who use drugs are not engaged in treatment. Barriers to seeking treatment include not perceiving the need to seek treatment [2,122], not knowing where to go for treatment, and not finding a program that matches patient needs [123]. A recent survey of opioid treatment programs also cited the lack of patient demand as a common barrier [10].	9A. Treatment systems should consult with people who use drugs to improve services targeted at them.
	9B. The National Institute on Drug Abuse should fund research on strategies to increase patient engagement and motivation to receive treatment. SAMHSA’s online tool educates patients on MOUD and directs individuals to tools to locate providers [124].