Lessons learned from housing first, rapid rehousing trials with youth experiencing homelessness.

Background: Youth, 18 to 24 years, experiencing homelessness (YEH) are recognized as having developmental challenges dissimilar to older adults. Yet, research on efforts to end homelessness and prevent or intervene in drug use and mental health problems among youth have lagged behind that of adults. The Housing First (HF) Model which underlies Permanent Supportive Housing (PSH) and Rapid Re-Housing (RRH) has become preferred over treatment-first models.