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Co-Occurring Conditions

Also known as: Co-Occurring Disorders, Comorbidity

Revised October 2019

What is a co-occurring condition?

Comorbidity Learn more basic facts and stats about co-morbidity (also called co-occurring conditions).

Co-occurring conditions is the term used to describe two or more disorders or illnesses that occur in the same person. They can exist at the same time, or one after the other. It is sometimes referred to as comorbidity. Below are some common mental health conditions that can be experienced in the same person in different combinations. It is important to know that having one of these conditions does not mean you will have another one.

  • anxiety
  • attention deficit hyperactivity disorder (ADHD)
  • autism spectrum disorders
  • depression
  • eating disorders
  • obsessive compulsive disorder (OCD)
  • post-traumatic stress disorder (PTSD)
  • substance use disorders (smoking, vaping, using drugs or alcohol)
  • thoughts of suicide

How can teens get help for co-occurring conditions without getting in trouble?

Photo of teen and father discussing co-occurring conditions.Photo by NIDA

Co-occurring conditions are very common in both teens and adults, and there is nothing to be ashamed of in asking for help. These mental health issues can improve when teens are willing to share their concerns with a trusted adult. For example, if you tell your pediatrician about your depression, and how drugs make you temporarily feel better, your doctor can then recommend a healthier approach to managing both problems or refer you to a counselor or other expert for help. To start the conversation with parents, guardians, or counselors, teens can show them this fact sheet to help explain how they are feeling.

Is addiction a mental illness?

Conceptual image of a man from side profile showing brain and brain activity©Shutterstock/Triff

Yes. Substance use disorders can change the brain, taking a person’s normal needs and desires and replacing them with the urge to seek and use drugs. These changes in the brain weaken the ability to control impulses that can lead to addiction, where a teen cannot stop using a drug despite negative consequences.

How common are co-occurring substance use disorders and other mental illnesses?

Many people who have a substance use disorder also develop another mental illness, just as many people who are diagnosed with mental illness are often diagnosed with a substance use disorder. Studies show that about half of people who experience a mental illness will also experience a substance use disorder at some point in their lives and vice versa.1, 2  

1 Ross S, Peselow E. Co-occurring psychotic and addictive disorders: neurobiology and diagnosis. Clin Neuropharmacol. 2012;35(5):235-243. doi:10.1097/WNF.0b013e318261e193.

2 Kelly TM, Daley DC. Integrated Treatment of Substance Use and Psychiatric Disorders. Soc Work Public Health. 2013;28(0):388-406. doi:10.1080/19371918.2013.774673.

Why do substance use disorders and other mental illnesses often co-occur?

It can be difficult to determine which condition started first. Scientists do know that if you have a mental illness like anxiety or PTSD, you are at higher risk for developing a substance use disorder. And if you have a substance use disorder, you are more at risk for developing mental health conditions. Research show that regular drug use can negatively affect areas of the brain involved in stress. In addition, drug use, like smoking marijuana regularly or drinking too much, can also make you worried that your parents or teachers will find out, and you could have some anxiety that you cannot stop using these substances.  

Scientists also know that some of these conditions run in families, so genetics might play a role in both substance use and other mental illnesses. Genes (inherited traits) also play a role in how you respond to a drug. For example, some teens try marijuana and have a psychotic reaction---feeling and seeing things that aren’t really there. This could be related to certain genes.

Secondly, environmental influences can lead to co-occurring conditions. Children who are bullied, abused, or who have experienced trauma are more at risk for substance use disorders and other mental illnesses.

Does self-medication for mental illness work?

Only trained medical professionals have the expertise to determine the safest and most effective ways to manage the discomfort you feel. Although some drugs may briefly help with mental illness symptoms, sometimes they can also make the symptoms worse and even lead to addiction. Additionally, when a person develops a mental illness, brain changes may enhance the rewarding effects of substances, making it harder to stop using the drugs.3

3 Santucci K. Psychiatric disease and drug abuse. Curr Opin Pediatr 2012;24(2):233-237. doi:10.1097/MOP.0b013e3283504fbf.

How do I know if I have a co-occurring condition?

If you drink or use drugs and/or have other mental health issues like anxiety or depression, it is critical that you be evaluated by a health professional. There are effective behavioral treatments and medications for mental illnesses and addiction. For a young person with symptoms of a mental disorder, the earlier treatment is started, the more effective it can be. Early treatment can help prevent more severe, lasting problems as you grow up, and can give you the skills to cope and manage these conditions throughout your life.

How do you know if you might have a mental health condition? Here is a list of signs to watch:

  • Do you smoke, drink alcohol, or use drugs?
  • Have you lost interest in things you used to enjoy?
  • Do you have low energy?
  • Do you sleep too much or too little, or are too sleepy throughout the day?
  • Are you spending more and more time alone, and avoid social activities with friends or family?
  •  Do you fear gaining weight, or diet or exercise too much?
  •  Do you hurt yourself (e.g., cutting or burning your skin)?
  • Do you engage in risky or destructive behavior, such as fighting, skipping classes, or illegal activities like trespassing or vandalism, alone or with friends?
  • Are you still feeling unable to cope with grief a long time after a loss or death of a loved one?
  • Do you have thoughts of suicide?
  • Do you have periods of unusual energy and activity, and need much less sleep than usual?
  • Do you sometimes think someone is trying to control your mind or do you hear things that other people cannot hear? 

If you use drugs or drink to overcome these feelings, it is important to seek help immediately. If you have developed some of these problems because of your use of drugs or alcohol, be sure to tell your health professional the whole truth about your behaviors, so he or she can best help you. Science tells us that the earlier you seek help, the better chance you have of leading a healthier life.

What should I do if someone I know needs help?

If you, or a friend, are in crisis and need to speak with someone now: 

  • Call the National Suicide Prevention Lifeline at 1-800-273-TALK (they don't just talk about suicide—they cover a lot of issues and will help put you in touch with someone close by)

If you want to help a friend, you can:

If a friend is using drugs, you might have to step away from the friendship for a while. It is important to protect your own mental health and not put yourself in situations where drugs are being used.

For more information on how to help a friend or loved one, visit our Have a Drug Problem, Need Help? page.

Where can I get more information?

NIDA Resources:

Other Government Resources:

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