Table 2.

Inclusion and Exclusion Criteria

Inclusion Criteria	Exclusion Criteria
• Research and non-research studies	• Documents addressing adults only or children only
• Documents relevant to any mental health and substance use service setting (i.e., community centers, hospitals, primary care)	• Documents not discussing services for mental or behavioral health or substance use (e.g., focus on physical health services)
• Documents focusing on adolescents, youth, young adults, or emerging adults	• Documents mentioning youth friendliness only in passing/not explaining youth friendliness in ways that answer the research question
• Documents irrespective of gender/sex, and ethnicity	• Documents specific to a particular treatment modality rather than the service setting as a whole (e.g., youth adaptations of cognitive-behavioral therapy)
• Only documents addressing mental/ behavioral health or addiction service settings
• Only documents specifically discussing the definition, characteristics, or expected impact of youth friendliness in these settings	• Conference presentation more than 3 years ago
	• Documents originating from developing countries, where youth culture may not be generalizable to that in developed countries