Co-Occurring Disorders and Other Health Conditions

What are Co-Occurring Disorders?

People with substance use disorders (SUDs) are at particular risk for developing one or more primary conditions or chronic diseases. The coexistence of both a mental illness and SUD is known as a co-occurring disorder, and is common among people in treatment.

People with mental illness are more likely to experience an SUD than those not affected by a mental illness. According to SAMHSA’s 2022 National Survey on Drug Use and Health, approximately 21.5 million adults in the United States have a co-occurring disorder.

It is important to note that combining medications used for SUD with anxiety treatment medications can have serious adverse effects. Common benzodiazepines include Xanax, Valium, Klonopin among others.

Co-occurring disorders may include any combination of two or more SUDs and mental disorders identified in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5-TR). No specific combinations of mental and substance use disorders are defined uniquely as co-occurring disorders.

Learn more about mental health and substance use disorders.

The most common mental disorders:

• Anxiety and mood disorders
• Schizophrenia
• Bipolar disorder
• Major depressive disorder
• Conduct disorders
• Post-traumatic stress disorder
• Attention deficit hyperactivity disorder

Patients being treated for mental disorders often misuse the following types of substances:

• Alcohol
• Tobacco
• Opioids
• Stimulants
• Marijuana
• Hallucinogens
• Prescription drugs

HIV, AIDS, and Viral Hepatitis

HIV, AIDS, and viral hepatitis are important public health concerns for both patients and health professionals in substance use disorder treatment programs. Use of medications for SUD treatment typically involves HIV and hepatitis antibody testing at admission, or a referral for antibody testing.

HIV and hepatitis prevention and reduced transmission are key goals of OTPs and other programs designed to treat substance use disorders. In addition, HIV testing and risk-reduction counseling, have been shown to stop or decrease drug use and related risk behaviors, including risky injection practices and unsafe sex.

HIV and AIDS in Treatment

Drug use is an important driver of the HIV epidemic. According to the CDC’s HIV and Injection Drug Use, about 1 in 10 new HIV diagnoses in the United States are attributed to injection drug use (2,492 cases) and male-to-male sexual contact and injection drug use (1,372 cases). CDC reports that in 2018, adult and adolescent people who inject drugs in the US accounted for 10 percent of all new HIV diagnoses.

HIV is transmitted by contact with the blood or other body fluids of an infected person. This can occur during unprotected sex or through the sharing of needles. In addition, untreated infected women can pass HIV to their infants during pregnancy, delivery, and breastfeeding. Alcohol and drug misuse can also worsen the symptoms of HIV, causing greater neuronal injury and cognitive impairment.

Hepatitis in Treatment

There are three major strains of hepatitis virus infection: hepatitis A, hepatitis B, and hepatitis C. People at high risk for infection can be protected by vaccination against hepatitis A and hepatitis B. Currently, there is no vaccination against hepatitis C.

• Hepatitis A – A self-limiting foodborne pathogen, can induce severe liver disease in drug users already infected with another hepatitis virus.
• Hepatitis B – Can be spread through sexual contact, blood transfusions, or by the re-use of contaminated needles.
• Hepatitis C – Injection drug use is the major source of hepatitis C infection in the United States, and a risk factor for contracting and spreading hepatitis C.

Learn more about hepatitis.

Resources and Publications

The following publications and resources highlight the link between substance misuse and comorbid HIV and AIDS:

• Ending the HIV Epidemic
• HIV and Injecting Drugs 101 from CDC (PDF | 603 KB)
• HIV and People Who Inject Drugs from CDC
• HIV Prevention Among Injection Drug Users from CDC
• TIP 37: Substance Abuse Treatment for Persons with HIV/AIDS – 2012
• TIP 53: Addressing Viral Hepatitis in People With Substance Use Disorders – 2011
• Viral Hepatitis and Injection Drug Users at the CDC
• What is Viral Hepatitis