Table 4: References for the frequently cited facilitators and obstacles to HR adoption

Theme 1: stakeholders’ characteristics

Education

Training in SUD or HR

Lack of training in SUD or HR

[64,65,66, 70, 76]

[32, 64, 66, 70, 71, 75, 77,78,79,80]

High education level

Low education level

[64, 67, 73]

[67, 73]

Sociodemographic characteristics

Young stakeholder age

Older stakeholder age

[73, 74, 81]

Beliefs and perceptions

Considering that the zero-tolerance approach may have a reverse effect

Maintaining personal beliefs stigmatizing drug use

[63, 82]

[75, 81]

Theme 2: clients’ characteristics

Factors related to SUD

SUD severity: moderate

SUD severity: severe

[74, 76, 81, 83,84,85,86]

[74, 76, 81, 83,84,85,86,87]

Therapy considerations

HR used as intermediate treatment goal

HR used as final treatment goal

[74, 76, 81, 83,84,85,86]

[74, 76, 81, 83, 84, 86]

Medical and/or psychiatric status

Comorbidity with a psychiatric disorder

[32, 64]

[71, 74, 75, 84]

Theme 3: factors related to HR

HR principles

HR focuses on clients’ needs and objectives

[32, 66, 69, 76, 79, 83, 87, 89]

HR creates a nonjudgmental framework

[32, 77, 80, 89]

HR efficacy and/or misconceptions

HR efficacy

Misconceptions related to HR

Perceptions of HR benefits and efficacy

Uncertainties about HR efficacy and/or dangerousness

[32, 64, 72, 91]

[32, 64, 74, 76, 78, 80]

HR seen as fostering clients’ engagement

Misunderstanding HR practices (e.g., lack of knowledge about treatment application)

[32, 64, 66, 75, 79, 88, 90, 91]

[32, 64, 71, 78, 79, 89]

External and other factors

Laws that favor HR adoption

Illegality of cannabis among a specific clientele

[66, 69, 82]

[74, 79, 82]

Theme 4: factors related to the workplace

General factors

Management leadership and support

Workplace philosophies that run counter to HR

[66, 71, 85, 91]

[32, 71, 74, 88]