Dual Diagnosis Explained: When Two Conditions Overlap

When someone is dealing with both a mental health condition and a substance use problem, one can make the other harder to manage. Treating only one often isn’t enough.  Federal guidance recommends treating both conditions together with a coordinated care team.

Treatment can also begin before withdrawal management is complete. In this guide, you’ll learn how dual diagnosis is identified, how the three treatment options differ and what to ask before enrolling in a program.

What Is Dual Diagnosis?

Dual diagnosis describes two conditions at once: at least one mental health disorder alongside at least one substance use disorder. It names a pairing, not a condition with criteria of its own. Furthermore, no single diagnosis sits behind the label.

You may hear clinicians call dual diagnosis a co-occurring disorder or CODs. Both conditions must be present on their own rather than one being caused by the other. This can take time to figure out. Some symptoms improve after a person stops using substances, while others stick around. That’s why treatment teams keep checking in and reassessing as recovery progresses. 

Substance use disorders and mental health disorders go hand in hand and affect more people than you might think. In 2025, 18.5 million adults in the United States had a mental illness alongside a substance use disorder, and 7.8 million of them had a serious mental illness, according to SAMHSA’s National Survey on Drug Use and Health (NSDUH). Among adults with a dual diagnosis, 42.6% received no treatment for either.

Common Co-Occurring Conditions

Some mental health conditions commonly occur alongside substance use disorders, so clinicians often expect to see them together. Anxiety, depression and psychosis related disorders are among them, along with two personality disorders (borderline and antisocial), post traumatic stress disorder (PTSD), attention deficit hyperactivity disorder (ADHD) and bipolar disorder. 

The connection goes both ways. According to the 2023 National Survey on Drug Use and Health, about 35% of U.S. adults with a mental health condition (other than a substance use disorder) also have a substance use disorder.

Why Mental Health and Substance Use Disorders Occur Together

There are three routes that connect mental health conditions and substance use disorders. These include: the risk factors they share, symptoms that lead a person to use and substance use that brings about or worsens a condition.

Genetics, stress and trauma are some of the factors that can increase a person’s risk of developing both conditions.

Another route is self medication, when someone uses substances to cope with symptoms they’re already experiencing. Substance use can also bring on mental health symptoms or make an existing condition worse.

There isn’t one set pattern for how these conditions develop. A mental health condition or substance use disorder can come first, and each person’s experience is going to be different.

Signs and Diagnosis

Many symptoms of substance use and withdrawal can imitate or mask other mental health symptoms. So, it can be difficult to separate the two. For instance, a mood that sinks in the first week off alcohol may be withdrawal rather than depression or the dread that lifts after a drink can look like an improvement in an anxiety disorder.

A thorough assessment can help a clinician understand what’s going on, and they might even repeat it after someone has spent some time without substance use. This helps them to see which symptoms improve and which ones stick around. 

Signs a clinician looks for include:

You also don’t have to finish withdrawal management before seeking help. There is no ‘wrong door’ by which people with co-occurring disorders arrive at treatment. 

Some people may still need medical support to withdraw safely, but that doesn’t mean they have to put off an assessment. If you’re already taking medication for opioid use disorder, you don’t need to stop taking it to be assessed.

Suicide Risk and Getting Help in a Crisis

People living with both a mental health condition and substance use disorder also face a higher risk of suicide. Suicide risk increases with nearly all combinations of these conditions. A history of trauma can raise the risk of self harm even further. 

If you or someone you know is thinking about suicide, help is one call, text or chat away. The 988 Suicide & Crisis Lifeline answers at 988 around the clock, and veterans can dial 988 and press 1. When someone is in immediate danger, call 911.

Dual Diagnosis Treatment: Integrated, Parallel and Sequential Care

Integrated care for dual diagnosis, where one team treats the mental health conditions at the same time as the substance use disorder, is the approach favored most often by federal agencies. However, some programs treat one condition before the other or in parallel, with separate clinicians handling each at the same time.

SAMHSA and NIDA are two of the federal agencies that call integrated care a best practice that leads to better health outcomes. However, this stance is not unanimous. In 2019, a Cochrane review by Hunt and colleagues found no high-quality evidence that any single psychosocial treatment outperformed standard care for people with serious mental illness and substance use disorder. 

Treatment may include behavioral therapies such as cognitive behavioral therapy (CBT), contingency management and motivational interviewing. Peer support runs alongside clinical work through addiction support groups and recovery group activities.  The right approach depends on the person’s needs and what the assessment shows. 

Some people do well with outpatient appointments, while others need the added support of residential treatment. The goal is to find a program that addresses both conditions and provides the level of care that makes sense for the person. 

Learn more about how co-occurring disorders treatment works and what to expect from different treatment options.

Medications When You Have a Dual Diagnosis

Medications for mental health conditions and for opioid or alcohol use disorders can often be used together. However, some combinations can increase the risk of overdose, so make sure your prescribers know about every medication you take. 

Pharmacotherapy often forms a core piece of treatment for co-occurring disorders, and effective medications are available for opioid, alcohol and nicotine use disorders. Keep in mind, though, most have not been well researched in people who have both.

The Food and Drug Administration (FDA) advises against withholding buprenorphine or methadone from people who take benzodiazepines. The combination does carry risks, though, so careful monitoring is important. It is also a good idea to keep naloxone on hand. You can get it without a prescription, and it can reverse an opioid overdose. 

ADHD is another mental health condition that can occur alongside a substance use disorder. Stimulants prescribed for it carry an FDA-required boxed warning about misuse, abuse and addiction, a risk that prescribers weigh.

How to Find Integrated Dual Diagnosis Care

When you contact a program, ask if they treat both mental health conditions and substance use. Ideally, you want a team that can address both as part of one treatment plan. Community behavioral health clinics, programs with mental health staff and FindTreatment.gov are good places to start.

The American Society of Addiction Medicine includes care for people with co-occurring disorders in its standards for every level of treatment. Certified community behavioral health clinics (CCBHCs) offer nine required services, including mental health and substance use care. As of July 2025, SAMHSA counted more than 500 of those clinics. They serve people regardless of age, ability to pay or where they live.

If you’re not sure where to turn, SAMHSA’s National Helpline can help you explore treatment options. You can also call or text 988 any time to reach the Suicide and Crisis Lifeline.

Insurance coverage is another piece to consider. Plans aren’t all required to cover mental health and substance use treatment, but when they do, federal parity laws generally require that coverage be comparable to medical and surgical benefits.

Frequently Asked Questions About Dual Diagnosis