The Link Between Mental Health and Substance Use Disorders

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Many people who are living with mental health disorders also are living with substance use disorders. Each condition increases the risk for the other, and the combination can be difficult to overcome. By understanding how these disorders overlap, the risks for each disorder, and how people can seek help, you can make a difference in the life of a friend or loved one.

What Is Substance Use Disorder?

According to the National Institute of Mental Health (NIMH), “A substance use disorder (SUD) is a mental disorder that affects a person's brain and behavior, leading to a person's inability to control their use of substances, such as legal or illegal drugs, alcohol, or medications. Symptoms can range from moderate to severe, with addiction being the most severe form of SUD."

Many people can drink socially or take pain medications without losing control or becoming addicted — but many cannot. Even when people are aware that they have an SUD or problem with substances, they may not be ready to change or know where to get help to stop using substances. Stigma also prevents people from seeking help.

What are Mental Health Disorders?

Mental health disorders, or mental illnesses, are common in the United States. NIMH estimates that nearly one in five U.S. adults is living with a mental illness. Mental illnesses include many different conditions that can be mild, moderate, or severe. Disorders can include any of the following (or combination of the following), along with others not listed:

  • Anxiety.
  • Attention-deficit/hyperactivity disorder (ADHD).
  • Bipolar disorder.
  • Borderline personality disorder.
  • Depression.
  • Eating disorders.
  • Obsessive-compulsive disorder (OCD).
  • Post-traumatic stress disorder (PTSD).
  • Schizophrenia.
  • Substance use and co-occurring mental disorders.

Mental Health and SUDs

Although mental illnesses and SUDs can occur together, one does not necessarily cause the other – but they can mutually increase risks.

Risk factors like stress or trauma, or a family history of mental illness or SUDs, can contribute to the development of SUDs or other mental disorders. Generational stress — such as from growing up in poverty or having a family member with addiction — also can contribute.

Because mental illness and SUDs can be so closely intertwined, it is usually best to treat them at the same time. People with mental illnesses may turn to drugs or alcohol in an effort to “self-medicate," increasing the risk of addiction.

Or, a person with an ongoing SUD may experience changes in the brain. Sometimes substance use results in psychiatric symptoms from intoxication or withdrawal syndromes (e.g., depressed mood, anxiety, trouble sleeping, low appetite, hallucinations) that often resolve once people stop using substances. Treatment can be a challenge, because symptoms can overlap. Multiple health care providers may need to be involved.

Risk Factors and Signs: SUDs

Anyone can develop a substance use disorder — it is a disease, not a personal failing. Some people may be more likely to develop an SUD depending upon their individual circumstances.

Some risk factors include:

  • Drug prescription for potentially addictive substances like opioids or benzodiazepines.
  • Exposure to illicit drugs.
  • Family history of SUD.
  • Family, social, or work problems.
  • Isolation or loneliness.
  • Mental health disorders.
  • Stress or trauma.

Signs of an SUD may include:

  • Behavioral changes (diminished work or school performance, inappropriate behavior, unexplained changes in habits, sudden mood swings).
  • Physical changes (bloodshot eyes, weight changes, tremors, and slurred speech).
  • Social changes (legal or financial problems, relationship changes).

If you think a friend or loved one may have an SUD, approach them and talk to them with empathy and respect. You may want to ask the person how their day is going, or you may want to involve others who know the person in order to determine how to proceed. It's important to do something.

If you are not sure where to begin, visit a trusted online source like or The Substance Abuse and Mental Health Services Administration (SAMHSA) is an agency within the U.S. Department of Health and Human Services; it also offers excellent resources.

Risk Factors and Signs: Mental Health Disorders

Just like diabetes or heart disease, mental health disorders can affect both the body and mind and, in many cases, can be successfully managed. There are many types of mental illness, but, like many other conditions, there are common risk factors.

A person may be at increased risk for mental health disorders due to:

  • Chronic medical conditions.
  • Family, social, spiritual, or work problems.
  • Family history (genetic predisposition).
  • History of abuse or neglect.
  • History of traumatic brain injury.
  • Isolation or loneliness.
  • Loss of a loved one.
  • Poverty or environmental stressors.
  • Stress or trauma.
  • Substance use disorders.

Signs of mental illness vary because there are so many different types of disorders. Some common signs often occur in a variety of disorders and may indicate a need for help:

  • Diminished work or school performance.
  • Erratic or inappropriate behavior or speech.
  • Expressed feelings of sadness (or looking/acting sad) or hopelessness.
  • Irritability or restlessness.
  • Loss of interest in hobbies or activities.
  • Poor hygiene.
  • Self-isolation.
  • Sleep changes.
  • Sudden mood swings.
  • Unexplained changes in habits.
  • Weight changes.

How Can You Help?

If you think someone is living with an undiagnosed mental health disorder, reach out by asking an open-ended question, like “How are you feeling today?" Listen, consider their response, and offer to connect them with resources. Be sure to speak respectfully and let the person know you genuinely care about their well-being.

If you are worried about the person's present actions – if they are behaving in a way that could endanger anyone – call 911. First responders can help to deescalate a situation and begin the process of finding help.

Often, the best place to start is a primary care provider's office. Ask if you can help schedule an appointment. You also may want to learn more about mental wellness. The American Mental Wellness Association provides screening tools and other resources: Or you could call the SAMHSA Treatment Referral Helpline at 877‑SAMHSA7 (1‑877‑726‑4727).

Treatment is tailored to the individual's needs and may include behavioral therapies and medications. A health care provider can help to determine what treatment may be best.

Behavioral therapies in particular can be effective for people with co-occurring substance use and mental disorders. Medications for alcohol, opioid, or nicotine use disorders may suppress withdrawal symptoms, decrease cravings, and enable people to focus better on behavioral therapies.

Whatever you do, be sure let the person know you are there to help. People with mental illness and/or SUDs may not be aware there's a problem and may need someone to begin the process of seeking help. By reaching out and checking in, you may help to save a life.