Addiction Disorders: The relationship between addiction and homelessness is complex and controversial. While rates of alcohol and drug abuse are disproportionately high among the homeless population, the increase in homelessness over the past two decades cannot be explained by addiction alone. Many people who are addicted to alcohol and drugs never become homeless, but people who are poor and addicted are clearly at increased risk of homelessness. Addiction does increase the risk of displacement for the precariously housed; in the absence of appropriate treatment, it may doom one's chances of getting housing once on the streets. Homeless people often face insurmountable barriers to obtaining health care, including addictive disorder treatment services and recovery supports. Source

It is believed that only about 20 to 40 percent of homeless have a substance abuse issue. In fact, abuse is rarely the sole cause of homelessness and more often is a response to it because living on the street puts the person in frequent contact with users and dealers.

The prevalence of mental illness and substance use among those experiencing homelessness is clear, but Kushel cautions that the vast majority of mental illness among the study participants is anxiety and depression. It’s likely the lack of resources exacerbates those conditions, rather than the illness causing the homelessness, she says.

“I think that the driving issue is clearly the deep poverty, that the median [monthly] household income for everyone in the household in the six months before homelessness was $960, in a state with the highest housing costs in the country,” she says. Other studies have noted that the end of pandemic stimulus payments and rising inflation has led to rents outpacing wages. The study notes that in 2023, California had only 24 units of affordable housing available for every 100 extremely low-income households.Source

Just because you know one or two people that were homeless and also had problems with addiction, doesn't mean the addiction caused their homelessness.