Mental health issues are a predictor of homelessness, and homelessness exacerbates and increases risk of mental health issues. Impairments in functioning often associated with mental health issues can lead to loss of employment and housing, and homelessness poses risks of increased stress, which is then associated with increased anxiety, depression, trauma, and traumatic brain injuries. Given all of the factors, it is not surprising that that two-thirds of surveyed homeless adults in the U.S. have a mental health and/or substance use disorder. One in nine Americans has an alcohol or drug problem (other than nicotine) compared to approximately one in three homeless persons. An estimated 20–25% of the homeless population in the United States suffers from serious mental health issues, compared to only 4–6% of the general population. An equally important statistic is that 24% of Americans age 12 or older smoke cigarettes, compared to approximately 70% of surveyed homeless people. In addition, as many as 80% of homeless persons tested have marked deficits in cognitive functioning, which would only serve to make mental health issues more severe or impairing. For more information on this topic see Adapting Your Practice: General Recommendations for the Care of Homeless Patients (National Health Care for the Homeless Council (NHCHC), 2010).