Compiling statistical information about homeless people is very difficult, but it is estimated that a high percentage of people who are homeless suffer from substance abuse and mental illness.

Drug Abuse and Homelessness

It is often asked which came first: homelessness or drug abuse? The answer is often difficult to ascertain. Substance abuse usually results in negative effects for the individual and their families, such as financial difficulties, rifts in families, legal trouble, and loss of housing. It is also thought that homelessness can compel some people to use drugs or alcohol to cope with their situation.

Heroin abuse among the homeless is a significant community problem across the country. Homeless individuals struggling with opioid addiction often find that heroin is easier and cheaper to obtain than prescription opioids. The extreme increase in counterfeit opioids, like oxycodone and hydrocodone, and the likelihood of the fake pills containing a fatal amount of fentanyl, coupled with a price tag most homeless persons cannot afford, often leads to heroin use. Heroin is cheaper to buy on the street than pills.

Prevalence of Substance Use Disorders

Based on the information provided by the U.S. Census Bureau, it is estimated that in 2017, about 253 million Americans were over the age of 18. Based on the information provided by the Substance Abuse and Mental Health Services Administration(SAMHSA), about 18.7 million Americans over 18 admitted to struggling with some form of substance use disorder in 2017.

Based on these figures, we can estimate that about 7.4 percent of people over the age of 18 struggled with some form of substance use disorder (a diagnosable substance abuse problem or addiction) in 2017.

How Prevalent is Substance Abuse Among the Homeless?

There are major issues in attempting to gather demographic information about individuals who are homeless, basically because they are homeless.

The latest estimates from the National Alliance to End Homelessness and SAMHSA suggest that approximately 35 percent of individuals who are homeless struggle with some form of substance abuse.  Approximately 26 percent of all people who are homeless struggle with some form of mental illness.

The current estimate is that slightly over 552,000 people are homeless in the U.S.

The Department of Housing and Urban Development (HUD) has provided estimates that suggest over half of the people living in supportive housing programs have a diagnosable psychiatric disorder, a diagnosable substance use disorder, or both.

The figures suggest that a large proportion of homeless people who have a mental illness and substance use disorders. Certainly, the rate of mental illness and substance abuse among this segment of the population is significantly higher than it is in the general population.

Current Homeless Substance Abuse Statistics

How many homeless are drug users? It is challenging to report a concrete number of homeless individuals abusing substances, but there are estimates.

Data from 2020, the latest year information was reported, indicated that on a given night in January 2020:

  • 27,487 people were homeless in Florida (Page 22)
  • 580,466 people were homeless in the country

A 2014 survey by the U.S. Conference of Mayors queried 25 cities about the top three causes of homelessness. Substance abuse was cited by 43% of cities, which tied for the third leading cause of homelessness.

Youth Homelessness Substance Abuse

Young people are also dealing with homelessness and drug abuse. An article on the Substance Abuse and Mental Health Services Administration (SAMHSA) website under Homeless Programs and Resources and youth notes the comorbidity between homelessness, mental health, and substance abuse. Youth are often resistant to seeking help from authority figures as they may fear being placed in foster care. Also, the article says that youth homelessness, mental health, and drug use all need to be treated simultaneously as all three of these factors reinforce each other. If one aspect is treated without the others, it does not benefit the young person.

Veteran Homelessness and Substance Abuse

Veterans are also affected by homelessness and substance abuse. Research from the Journal of Opioid Management with the U.S. Department of Veterans Affairs found that veterans who sought treatment for opioid use disorder were 10 times more likely to have experienced homelessness versus the general veteran population.

Women Who are Mothers Homelessness and Substance Abuse

Women who are mothers are also experiencing homelessness and substance abuse. A 2010 SAMHSA report stated:

92% of homeless mothers have experienced physical and/or sexual abuse during their lifetime, which measures up to three times the rate of post-traumatic stress disorder (PTSD), and twice the rate of drug and alcohol dependence.

Reasons for Homelessness

The National Coalition for the Homeless (NCH) offers a list of the major contributions to becoming homeless.

  • Foreclosures on homes have increased significantly over the past 10 years (by nearly a third over the previous period), leading to loss of housing among renters and homeowners who are evicted.
  • Medical costs associated with accidents or health problems are some of the most common reasons for going bankrupt. Bankruptcy due to medical bills can be a significant contributor to homelessness.
  • Funding cuts for public assistance programs have increased the potential for low-income or disabled individuals to become homeless.
  • The federal government’s support for low-income housing has decreased, resulting in a lack of low-income housing for people who need it.
  • Economic factors, such as a proliferation of lower-income jobs that are not sufficient to pay for housing, may contribute to homelessness.

The Connection Between Homelessness and Substance Abuse

Although becoming homeless may be a risk factor that can contribute to the development of substance use, the research does not suggest that homelessness causes substance abuse in the majority of cases. Instead, there are other reasons that there is a higher proportion of mental illness and substance abuse issues among the entire group of individuals who are homeless.

Homelessness and Mental Illness

According to the American Psychiatric Association (APA), there is a strong relationship between being diagnosed with any psychiatric/psychological disorder and also having a co-occurring diagnosis of a substance use disorder.

The relationship is bidirectional, such that if someone is diagnosed with nearly any psychiatric disorder, they are at an increased risk to also be diagnosed with a substance use disorder. If they are diagnosed with any form of a substance use disorder, they are also at an increased risk to be diagnosed with some other form of mental illness.

Given the high rate of mental illness that occurs in homeless people, one would expect that there would also be a significantly increased rate of substance use disorders in this group.

Moreover, individuals with more serious forms of mental illness are even more likely to have a co-occurring substance use disorder. They would also be expected to have difficulty providing a home for themselves without significant assistance.

More serious forms of mental illness can lead to problems functioning within society, and this can contribute to homelessness, family conflicts, and social isolation among this group.

Thus, it is more likely that issues with mental illness and substance abuse result in someone becoming homeless than it is that being homeless leads to an increased risk for substance abuse or mental illness.

High Levels of Stress Among Homeless Individuals

The significant stress associated with unemployment, lack of social support, family disputes, and peer pressure contributes to substance use disorder in anyone. Homeless individuals are exposed to stressful conditions that can further increase the risk that they will turn to drugs or alcohol.

What Substances are Commonly Abused by the Homeless?

Alcohol is the most common substance of abuse used by individuals who are homeless. Alcohol is a top substance of abuse for the homeless population due to it being easily available and cheap to buy. Mini bottles of alcohol can be found in liquor stores and sometimes in convenience stores for as little as $1.50.
Other drugs that are commonly sold on the street, like heroin, cocaine, and methamphetamine, can also be significant drugs of abuse. Injection drug use, like that of heroin, cocaine, and meth, contributes significantly to homeless individuals with HIV and AIDS, and hepatitis. The use of shared needles, along with the high that these drugs give, usually results in unsafe sex and other risky behaviors. 

Other drugs abused by homeless people might also include synthetic cannabinoids, such as “spice.”  While it may be thought of as a legal alternative to marijuana and easily obtained in shady convenience stores, spice is highly addictive and can cause adverse side effects, like rapid heart rate, suicidal thoughts, and overdose. Death is a possibility also. Tobacco use disorders may be common among homeless individuals. 


The strategy to address the complications associated with the high rate of substance use disorders in homeless individuals is not an easy one.

Better access to quality mental health care treatment for this group and access to affordable housing could go a long way in addressing the situation.  Providing job skills training for these individuals has been proposed to decrease substance abuse.

Other proposals, such as community injection site programs, have been proposed to control the spread of disease related to needle sharing among this segment of the population.

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