According to the National Survey on Drug Use and Health (2018), 9.2 million adults in the U.S. experienced both mental illness and a substance use disorder.

Addiction & Mental Health

Co-occurring is also called comorbidity or dual diagnosis—when two disorders or illnesses occur in the same person, simultaneously or one after another. Comorbidity also implies that the illnesses interact, affecting the course and prognosis of both. 1

Co-occurring conditions that involve addiction and mental health are common because similar areas of the brain are involved with both. About 50% of people with a mental health issue will also experience a substance use disorder and vice versa. 2

What causes co-occuring disorders?

Research has shown that mental illness and drug use involve similar areas of the brain. The areas of the brain that process “reward” feelings and that respond to stress are both affected by mental health disorders and by using drugs.

Drug use affects the brain and can aggravate the symptoms of existing mental health conditions. Often, someone with a mental health condition may try to self-medicate by treating symptoms of anxiety or depression by using alcohol or drugs. While the substances may give temporary relief, when they wear off, their symptoms are often much worse.

What do addiction and mental health disorders have in common?

Genetics

Addiction and mental health disorders are both brain diseases. Genetics can predispose a person to addiction and can also put a person at higher risk for developing a co-occurring mental health issue.

Development

A young person’s brain is still developing until they reach age 25 and an adolescent brain that is still developing is at an increased risk for both addiction and mental health disorders. If a young person begins using drugs or alcohol during this time, that drug use can potentially affect the brain and make it more likely to develop a mental illness. The opposite is also true: A person who develops a mental illness at a young age may also be more susceptible to developing a substance use disorder. Learn more about our prevention programs.

Exposure

Exposure to high levels of stress can trigger mental health disorders or substance abuse disorders. This might include living in an unsafe environment, neglect, poverty, trauma, physical or sexual abuse, excessive stress, or other negative experiences the brain has difficulty processing. And, adolescent stress can cause significant changes in adult brains.

People who struggle with PTSD are up to four times as likely to battle addiction.

Emotional signs of stress can include:

  • Depression
  • Anxiety
  • Irritability
  • Mood Swings
  • Compulsive behavior
  • Memory & concentration problems

How are co-occuring disorders treated?

The best treatment for co-occurring disorders is to take an integrated approach that addresses both the person’s diagnosed mental health condition and addiction. Successful treatments include behavioral therapies and medications, used together as part of a personalized plan.

1 NIDA https://www.drugabuse.gov/publications/research-reports/common-comorbidities-substance-use-disorders/introduction
2 SAMHSA https://www.samhsa.gov/medication-assisted-treatment/treatment/common-comorbidities
3 NIDA https://www.drugabuse.gov/publications/drugfacts/comorbidity-addiction-other-mental-disorders