link between mental illness and substance use disorder

The Link Between Mental Illness and Substance Use Disorders

The challenges of mental health and addiction can be connected for some people. For example, someone with a mental illness may turn to drugs or alcohol to alleviate their symptoms. Likewise, someone who is struggling with an addiction might develop symptoms of a mental illness because of the overuse of certain substances. The link between mental illness and substance use disorders should be recognized and addressed, especially during Mental Health Month.

Addiction as a Mental Illness

The National Institute of Mental Health (NIMH) says that addiction to drugs or alcohol is, in itself, a mental illness. The experts within the organization, a division of the National Institutes of Health, explain that substance use disorder changes normal desires and priorities. It changes normal behaviors and interferes with the ability to work, go to school, and to have good relationships with friends and family.

Dual Diagnosis

Research has found that about half of those people who experience a mental illness during their lives will also experience a substance use disorder and vice versa. When someone experiences a mental illness and a substance use disorder simultaneously, it is referred to as a dual diagnosis or a co-occurring disorder. Over 9 million adults in the US experienced both mental illness and a substance use disorder in 2018.

According to the National Alliance on Mental Illness (NAMI), either disorder—substance use or mental illness—can develop first. People experiencing a mental health condition may turn to alcohol or other drugs as a form of self-medication to improve the mental health symptoms they experience. However, research shows that alcohol and other drugs worsen the symptoms of mental illnesses.


According to the US Department of Health and Human Services (HHS), the link between mental illness and substance use disorder sometimes occurs because:

  • Certain illegal drugs can cause people with an addiction to experience one or more symptoms of a mental health problem
  • Mental health problems can sometimes lead to alcohol or drug use, as some people with a mental health problem may misuse these substances as a form of self-medication
  • Mental and substance use disorders share some underlying causes, including changes in brain composition, genetic vulnerabilities, and early exposure to stress or trauma.

Substance use problems occur more frequently with certain mental health problems, including:

  • Depression
  • Anxiety disorders
  • Schizophrenia
  • Personality disorders.


As with every disease, the symptoms of mental illness and substance use disorder are different for each person. There are many combinations of dual diagnosis, which can affect the specific symptoms. To determine whether there is a link between mental illness and substance use disorder within an individual, mental health clinics are starting to use alcohol and drug screening tools to help identify people at risk for drug and alcohol abuse.

Symptoms of substance use disorder can include:

  • Withdrawal from friends and family
  • Sudden changes in behavior
  • Using substances under dangerous conditions
  • Engaging in risky behaviors
  • Loss of control over use of substances
  • Developing a high tolerance and withdrawal symptoms
  • Feeling like you need a drug to be able to function.

Symptoms of a mental health condition can also vary greatly. Warnings signs, such as extreme mood changes, confused thinking or problems concentrating, avoiding friends and social activities, and thoughts of suicide, may be reason to seek help.


Professional treatment for a person with a mental illness and a substance use disorder must include a focus on both issues. Treatment for both mental health problems and substance use disorders may include rehabilitation, medications, support groups, and talk therapy.

Detox may be the first step toward treating the substance use disorder, followed by integrative healing methods to address mental health issues such as anxiety, phobias, depression, and self-destructive patterns. Certain medications may also be used for treating mental illnesses as well as for helping people who are experiencing substance use disorders manage their withdrawal symptoms, promoting their successful recovery.

Connect with Recovery Without Walls for Help During COVID-19

Recovery Without Walls provides treatment of dual diagnoses, chemical dependency, mental health issues, and problems with alcohol. During Mental Health Month, and especially during the COVID-19 pandemic, we encourage you to email or call us for care and answers to your questions. Our providers continue to work to help you through treatment and recovery. We focus on evidence-informed research, exceptional psychotherapy, and integrative healing methods. Contact us today to learn more about the link between mental illness and substance use disorder and to get help.