Every day, as many as 2.8 million runaway and homeless youth live on the streets of America. Of the many significant problems they face, perhaps the most detrimental to their long-term health and survival is substance abuse. Drug and alcohol prevalence among homeless youth and young adults is astounding; 83 percent have used alcohol, 75 percent have used marijuana and approximately 30 percent have used illicit drugs. 

Substance use among homeless youth and young adults has been linked to child abuse, parental substance abuse, psychological distress and deviant peers. However, little is known about the role of protective mechanisms to offset or change risk for substance use and abuse for this vulnerable population. 

This research is designed to help improve the lives of homeless youth and young adults by preventing substance abuse and guarding against future health risks. To support this goal this goal, this study aims to: 

1. Empirically identify protective factors, including psychological and social resources, and their association with substance use among a sample of homeless youth and young adults. Empirically identify primary and secondary stressors to determine their association with substance use. 
2. Determine whether protective factors mediate the relations between childhood disadvantage and substance use.
3. Determine the utility of an innovative data collection method, short message service (SMS), to gather multiple daily data on substance use. 

Data collection methods will include a face-to-face structured interview with 120 homeless youth and young adults, through two service agencies. This will be followed up with multiple daily text questions sent to respondents over a 30-day period. The assessment technology, SMS surveying, has the potential to significantly improve the reliability and validity with which substance-use data on homeless youth and young adults are gathered. The ability to study changing patterns of substance use and uncover successful protective factors will inform intervention strategies to improve health outcomes for homeless youth and young adults — and ultimately prevent life on the streets from becoming permanent.