Understanding Co-Occurring Disorders: Why Integrated Treatment Is Essential for Recovery

July 22, 2025

Lauren Grawert, MD, Author & Addiction Psychiatrist, Chief Medical Officer, Aware Recovery Care

Tom O’Connor, Editor & Publisher

SAMHSA estimates that 45% of adults with a substance use disorder also have a co-occurring mental health condition.  The three most popular theories are the self-medication theory, the gene variants theory, and the kindling effect theory.  

• Self-Medication. Drinking to cope with the distress of an underlying mental health disorder is self-medication. Sometimes, people develop a substance use disorder because the effects of drugs and alcohol alleviate symptoms of PTSD, bipolar disorder, depression, and/or anxiety, to name a few. Part of recovery is learning how to cope with distress, and this can include symptoms of mental illness. 

• Gene Variants. Numerous studies have demonstrated that substance use disorders and mental health disorders run in biological families. The gene variants theory proposes that specific genes linked to substance use disorders are also linked to mental health disorders. For example, you may have heard that people with untreated ADHD are more likely to develop a substance use disorder. The gene variants theory hypothesizes that genetic mutations that result in more hyperactive, impulsive, and reward-driven brains (ADHD) are also mutations that make brains more vulnerable to substance use disorders. Currently, scientists are identifying these specific mutations to create a “genetic risk factor” score that may help predict who is more likely to develop co-occurring disorders based on their DNA sequence. 

  
  

• Kindling Effect. When trying to start a fire, having only one plank of wood goes only so far. But if you add lighter fluid and small sticks around the plank, the likelihood of a blazing flame skyrockets. That’s the basis of the kindling theory. Having an initial mental disorder, whether psychiatric 0or substance use, changes the neural pathways in the brain: strengthening some, lessening others, and making some more sensitive. These changes act as kindling, increasing the likelihood that a future stressor or behavior will result in a secondary disorder. Unlike the gene theory that locates risk within one’s DNA, the kindling effect states that the progression of one disease and its changes to the brain are what make it more vulnerable to a second disorder. The kindling effect highlights the importance of early intervention in preventing the development of secondary disorders.

  
  

Author Lauren Grawert is an Addiction Psychiatrist and Chief Medical Officer at Aware Recovery Care. She has authored numerous articles for the Vital Voyage Blog and serves as a member of its Editorial Advisory Board. Lauren takes us through Understanding Co-Occurring Disorders: Why Integrated Treatment Is Essential for Recovery.

What Are Co-Occurring Disorders?

Co-occurring disorders, also known as dual diagnoses, refer to the presence of both a substance use disorder (SUD) and a mental health condition in the same person. This combination is much more common than most people realize. More than half of those with a substance use disorder will also experience a mental illness at some point in their lives, and vice versa.

Common examples of co-occurring pairs include depression and alcohol use disorder, anxiety and stimulant misuse, and Post Traumatic Stress Disorder (PTSD) and opioid use disorder. Among individuals with a military or combat background, concurrent PTSD and alcohol use disorder are also frequently seen. These disorders can happen in any order or combination, but their interaction usually makes both conditions worse, creating additional challenges for recovery.

Why Do These Disorders Often Happen Together?

Managing Stress

The overlap between mental health and addiction isn’t accidental — it’s deeply rooted in how people experience and try to manage distress. Those dealing with emotional discomfort like anxiety, sadness, intrusive memories, or emotional numbness often turn to substances as a form of self-medication: a quick way to escape uncomfortable thoughts and feelings. The desire to escape suffering is a universal human experience.

Drugs like alcohol, cannabis, opioids, and others can provide temporary emotional relief — a shift in mood and perception. For someone with untreated depression or trauma, that change can feel like a lifeline. Unfortunately, this coping method is typically unsustainable. It often leads to dependency and worsening mental health symptoms over time. I call it the trampoline effect: emotional distress temporarily eases with substance intoxication. But as the neurological effects wear off, the mood symptoms bounce back even stronger. To reduce the more substantial distress and build tolerance, people often use even larger amounts of their drug of choice. It becomes a vicious cycle on the mood trampoline. 

From a neurobiological perspective, chronic stress and emotional dysregulation impact the same brain circuits involved in reward, impulse control, and mood regulation. When these systems are out of balance, individuals become more prone to psychiatric conditions and substance misuse. It’s not a sign of weakness; it’s simply human biology.

Why It’s Essential to Treat Both Disorders Simultaneously

Historically, mental health and addiction treatment systems have operated separately. Patients were often told they needed to achieve sobriety before receiving treatment for depression or anxiety. Conversely, those seeking help for mental illness might be turned away if they were actively using substances. When I worked for a large HMO just a few years ago, we had “chemical dependency therapists” and “mental health therapists,” but not therapists who addressed both conditions together. This fragmented approach is outdated and ineffective.

Extensive research and clinical experience demonstrate that treating only one disorder while neglecting the other results in poorer outcomes. For example, a patient with untreated bipolar disorder who stops using cocaine without receiving mood stabilization faces a very high risk of relapse. Their mood instability becomes more evident and severe. Similarly, addressing PTSD without tackling ongoing alcohol misuse can hinder meaningful therapeutic progress and reduce medication effectiveness.

Integrated treatment—where both mental health issues and substance use disorders are managed simultaneously by the same team—is the gold standard. This method improves outcomes by addressing the underlying causes of distress and the behaviors that sustain the cycle of addiction. It also creates a more compassionate, comprehensive, and stigma-free environment for recovery.

Modern Approaches to Integrated Care

For decades, treatment systems operated under the mistaken belief that mental illness and addiction should be treated separately. Today, we understand better. Co-occurring disorders are the norm, not the exception. They are a natural part of the human experience and stem from a universal desire to escape suffering. This is a feature of the system, not a flaw. They originate from interconnected biological and emotional vulnerabilities and must be addressed together. Integrated treatment isn’t just more effective—it’s vital. 

Recovery becomes achievable when we stop asking patients to choose between their diagnoses and instead provide compassionate care for the whole person. If you or someone you love is struggling with a co-occurring disorder, know that healing is possible, and you don’t have to select which part of yourself deserves care. You deserve support for everything. 

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Lauren Grawert is an Addiction Psychiatrist, Chief Medical Officer, Aware Recovery Care.

She is a double board-certified Addiction Psychiatrist who treats both adolescents and adults struggling with both mood and anxiety disorders and substance use disorders.

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