Co-Occurring Disorders: What They Are and Why They Require Specialized Treatment

Mental health conditions and addictions are each complex in their own right, but when the two occur together, understanding what is happening can feel even more difficult. That said, complexity does not mean confusion has to last, and it certainly does not mean effective treatment is out of reach.

If you, or someone close to you, is living with a co-occurring condition, the first step is gaining a clearer understanding of what this actually means. From there, it becomes much easier to identify the kind of support and treatment needed to work toward lasting recovery.

This article explains what co-occurring disorders are, the most common forms they take, and why co-occurring disorders need integrated treatment to support lasting recovery.

What Are Co-Occurring Disorders?

When someone has both a mental illness and a substance use disorder at the same time, clinicians refer to this as a co-occurring disorder or a dual diagnosis. In the U.S., this overlap is very common, with national surveys finding that around half of people who have had a serious mental illness have also experienced a substance use disorder, and vice versa.¹

Co-occurring disorders can significantly complicate the treatment process, as care must address two already complex conditions at the same time. For example, untreated depression can become a major driver of relapse, while ongoing substance use can worsen psychiatric symptoms and make mental health treatment less effective.

Understanding the Relationship Between Mental Health and Addiction

If you are learning about a dual diagnosis for the first time, a common question many people ask is, “Which comes first?” It is a completely valid question, but the answer is not always straightforward. Research emphasizes that there is a two-way connection, known as a bidirectional relationship, where each condition can worsen the other.² Understanding this relationship and how mental health and addiction interact is essential for effective treatment.

Mental Health Issues Fueling Addiction

Many mental health conditions involve emotional dysregulation ³, and when emotions feel overwhelming, healthy coping strategies can become more difficult to maintain. Alcohol or drugs can then feel like a quick way to calm those intense feelings.

Mental health conditions can also cause ongoing stress that disrupts the body’s stress response system. When substances are used to manage this stress, the risk of developing an addiction increases.⁴

These actions relate heavily to what researchers call the ‘self-medication hypothesis’, which states that those with mental health conditions are more likely to soothe their symptoms with drugs or alcohol.⁵

The problem is that while substances may offer temporary relief, they come at a cost. When the effects wear off, the original distress remains the same, if not worse than before. When this cycle repeats, the likelihood of developing dependence continues to grow.

Studies have shown that mental illness frequently precedes substance misuse, which supports the self-medication hypothesis.⁵

Addiction Creating New Mental Health Issues

On the other side of the coin, chronic addiction can also trigger psychiatric disorders. 

For example, heavy alcohol use disrupts mood-regulating circuits and can lead to mood disorders. One review found that 40–60% of people with alcohol use disorder experienced depressive episodes linked to their drinking.⁶

There is also evidence that early substance use increases the risk of later mental health conditions, with cannabis use during adolescence consistently linked to higher rates of psychosis in adulthood.⁷

Understanding the Reality of These Changes

Policy changes and public initiatives help open the door to mental health support, but awareness alone rarely leads to recovery. Knowing that stigma exists, or even understanding why it exists, doesn’t automatically make it easier to ask for help. What these reforms do is remove some of the pressure that has historically sat on people to justify their own suffering before reaching out.

One law change isn’t going to dramatically improve the mental health landscape overnight, but every time a new law gets passed or a new proposal is discussed, it brings the topic to the public. It shows everyone that mental health is serious—serious enough to change laws and consider ways to improve it.

As these barriers are lowered, the internal hesitation that some people have to seek help begins to soften. When this starts to happen, stigma loses some of its power, and along with it, the doors to mental health treatment start to seem a little more open than they once did.

Common Types of Dual Diagnosis

In theory, any addiction could co-occur with any psychiatric condition, meaning there are many possible combinations of dual diagnosis. That said, there are some pairings that appear more frequently than others. 

Depression and Addiction

One large review found that around 16.5% of people with major depression also have an alcohol use disorder.⁶ This is far higher than the rate in the general population, raising the question of why this link is so strong. The answer often comes back to the self-medication hypothesis, where some of those living with depression may resort to drinking to numb the sadness they feel. 

Unfortunately, this pattern can backfire, as while a substance initially raises mood, long-term use can affect serotonin levels and worsen the depression.⁸ The result is a vicious cycle of drinking to feel better while falling deeper into depression.

PTSD and Addiction

PTSD and addiction are also very tightly linked. Surveys have shown that nearly half of people with PTSD also met the criteria for a substance use disorder.⁹

One common reason, again, is the self-medication of trauma symptoms, like hypervigilance, panic, nightmares, or flashbacks. Studies confirm this, finding that when PTSD symptoms spike, cravings for drugs or alcohol rise in parallel.⁹ Research has found that people with PTSD often use depressants, like alcohol, expressly to blunt flashbacks.⁹

Schizophrenia and Addiction

Schizophrenia has one of the highest rates of dual diagnosis, with research showing that up to 47% of people with the disorder have an SUD.¹⁰

Specifically, nicotine has been found to be one of the most common substances used by people with schizophrenia, with up to 70-80% smoking cigarettes to help with what they describe as improved concentration.¹ 

However, it is important to understand the difficulty that researchers face, specifically in the schizophrenia and addiction discussion. Drug use can create symptoms that closely resemble schizophrenia, so it can be difficult to clearly identify which symptom patterns belong to schizophrenia and which stem from substance use.¹¹

Neurodivergent Conditions and Addiction

Among all neurodivergent conditions, ADHD’s link to addiction is the strongest. Studies estimate that about 1 in 4 young adults with an SUD also meet the criteria for ADHD.¹²

It is thought that those with ADHD have impaired impulse control and signaling, meaning that drugs or alcohol can temporarily “fix” symptoms of ADHD.¹²

This could make those with ADHD especially vulnerable to early substance use and potentially addiction.

Why Is Specialized Care Needed for Co-occurring Disorders?

There are many treatment challenges for dual diagnosis patients, and research shows that if one or both conditions go untreated, it can leave the door open for more serious outcomes. 

This could include:¹³

• Experiencing stronger, negative mental health symptoms
• Difficulty coping with everyday life
• Relapse risks
• Increased hospital visits
• Suicidal ideation

This is exactly why specialized, integrated care is needed, so both aspects of the dual diagnosis are treated together.

What Does Specialized Treatment for Co-Occurring Disorders Involve?

Mental health conditions and addictions are very complex, so it’s no surprise that when it comes to treatment, a multidisciplinary team is formed. This may include therapists and medical professionals who provide support within their respective areas of expertise. This integrated behavioral health treatment has been shown to lead to much more effective outcomes.¹³

If necessary, treatment may begin with detoxification, which allows the body to rid itself of any substances. Then, once the substance is cleared, therapists can offer a range of evidence-based approaches for co-occurring disorders. These are designed to address both conditions simultaneously. 

Cognitive Behavioral Therapy (CBT)

CBT teaches patients to recognize and actively change unhelpful thoughts that impact mental health and addiction challenges. This might mean that therapists may combine standard addiction relapse prevention skills with strategies to address depressive thoughts.

Dialectical Behavior Therapy (DBT)

DBT focuses on emotional regulation, distress tolerance, interpersonal skills, and mindfulness, which are particularly important for people living with a dual diagnosis. For example, a person might learn coping or mindfulness skills to handle negative emotions and urges to use.

Clinical trials have found that DBT decreased substance abuse in patients, specifically those with borderline personality disorder, and shows promise for other co-occurring cases as well.¹⁴

Acceptance and Commitment Therapy (ACT)

ACT helps people change how they relate to difficult thoughts and feelings, rather than trying to battle against them. 

For example, instead of trying to overcome cravings or low mood, ACT teaches people to notice these experiences as they arise and allow them to exist without automatically reacting.

How AMFM Can Help

If you, or someone you love, is currently dealing with a dual diagnosis, now is the right time to reach out for support. 

With the right integrated behavioral health treatment options in place, you put yourself in the best possible position of recovery. 

AMFM provides expert treatment options for adult dual diagnosis care. Many of the therapies that we use with our clients, like CBT and DBT, can be adapted for co-occurring disorders. 

If you need more information on specialized treatment for co-occurring conditions or if you’d just like to learn more about dual diagnosis and mental health, contact us today. A member of our team would be more than happy to assist you.

References

1. National Institute on Drug Abuse. (2020). Common comorbidities with substance use disorders: Research report. National Institutes of Health. https://www.ncbi.nlm.nih.gov/books/NBK571451/
2. Logge, W. B., Lee, K., & Yen, C.-F. (2024). Editorial: Dual disorders in addiction and mood disorders: Comorbidity or specific diagnosis? Frontiers in Psychiatry, 15, Article 1490922. https://doi.org/10.3389/fpsyt.2024.1490922
3. González-Roz, A., Castaño, Y., Krotter, A., Salazar-Cedillo, A., & Gervilla, E. (2024). Emotional dysregulation in relation to substance use and behavioral addictions: Findings from five separate meta-analyses. International Journal of Clinical and Health Psychology, 24(3), 100502. https://doi.org/10.1016/j.ijchp.2024.100502
4. Sinha, R. (2008). Chronic stress, drug use, and vulnerability to addiction. Annals of the New York Academy of Sciences, 1141(1), 105–130. https://doi.org/10.1196/annals.1441.030
5. Harris, K. M., & Edlund, M. J. (2005). Self-medication of mental health problems: New evidence from a national survey. Health Services Research, 40(1), 117–134. https://doi.org/10.1111/j.1475-6773.2005.00345.x
6. Revadigar, N., & Gupta, V. (2022). Substance-induced mood disorders. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK555887/
7. West, M. L., & Sharif, S. (2023). Cannabis and psychosis. Child and Adolescent Psychiatric Clinics of North America, 32(1), 1–14. https://doi.org/10.1016/j.chc.2022.07.004
8. Castle, M. E., & Flanigan, M. E. (2024). The role of brain serotonin signaling in excessive alcohol consumption and withdrawal: A call for more research in females. Neurobiology of Stress, 30, 100618.https://doi.org/10.1016/j.ynstr.2024.100618
9. McCauley, J. L., Killeen, T., Gros, D. F., Brady, K. T., & Back, S. E. (2012). Posttraumatic stress disorder and co-occurring substance use disorders: Advances in assessment and treatment. Clinical Psychology: Science and Practice, 19(3), 283–304. https://doi.org/10.1111/cpsp.12006
10. Masroor, A., Khorochkov, A., Prieto, J., Singh, K. B., Nnadozie, M. C., Abdal, M., Shrestha, N., Abe, R. A. M., & Mohammed, L. (2021). Unraveling the association between schizophrenia and substance use disorder: Predictors, mechanisms, and treatment modifications. Cureus, 13(7), Article e16722. https://doi.org/10.7759/cureus.16722
11. Blum, K., Oscar-Berman, M., Badgaiyan, R. D., Palomo, T., & Gold, M. S. (2014). Hypothesizing dopaminergic genetic antecedents in schizophrenia and substance-seeking behavior. Medical Hypotheses, 82(5), 606–614. https://doi.org/10.1016/j.mehy.2014.02.019
12. Barbuti, M., Maiello, M., Spera, V., Pallucchini, A., Brancati, G. E., Maremmani, A. G. I., Perugi, G., & Maremmani, I. (2023). Challenges of treating ADHD with comorbid substance use disorder: Considerations for the clinician. Journal of Clinical Medicine, 12(9), 3096. https://doi.org/10.3390/jcm12093096
13. Vekaria, V., Bose, B., Murphy, S. M., Avery, J., Alexopoulos, G., & Pathak, J. (2021). Association of co-occurring opioid or other substance use disorders with increased healthcare utilization in patients with depression. Translational Psychiatry, 11(1), Article 202. https://doi.org/10.1038/s41398-021-01372-0
14. Dimeff, L., & Linehan, M. (2008). Dialectical behavior therapy for substance abusers. Addiction Science & Clinical Practice, 4(2), 39–47.https://doi.org/10.1151/ascp084239