What Is Dual Diagnosis?
Dual diagnosis—also referred to as co-occurring disorders or comorbid conditions—describes individuals who experience both a substance use disorder and a mental health condition simultaneously. In some cases, both conditions develop at the same time, while in others, one may trigger or worsen the other. Accurately diagnosing dual diagnosis can be challenging, especially in traditional healthcare settings where symptoms of substance abuse and withdrawal can closely mimic those of psychiatric disorders. Identifying and addressing both conditions is essential for long-term recovery and success in addiction treatment.
Who Is Affected by Dual Diagnosis?
According to a 2014 National Survey on Drug Use and Health, approximately 7.9 million U.S. adults live with both a mental illness and a substance use disorder. Among adolescents ages 12–17, drug use is significantly higher among those diagnosed with depression. Teens with depression are more likely to use marijuana, inhalants, hallucinogens, prescription medications, and to engage in heavy alcohol consumption. Research shows that 50–90% of teens seeking treatment for substance use also have an underlying psychiatric disorder.
Common Mental Health Symptoms in Dual Diagnosis Include:
- Mood instability or extreme emotional swings
- Persistent anxiety or nervousness
- Difficulty focusing or making decisions
- Feelings of hopelessness or disconnection
- Confusion or memory lapses
- Suicidal thoughts or ideation
What Are the Symptoms of Dual Diagnosis?
Because dual diagnosis can involve many combinations of disorders, the symptoms can vary widely. Below are some signs associated with substance use disorders:
- Neglecting responsibilities
- Stealing to support substance use
- Withdrawing from friends and family
- Using more of a substance over time
- Persistent cravings and inability to stop
- Impulsivity, nervousness, or emotional numbness
- Experiencing withdrawal symptoms when trying to quit
- Feeling guilty or ashamed about substance use
- Feeling dependent on the substance to function
- Defensiveness when questioned about habits
What Causes Dual Diagnosis?
Multiple factors contribute to the development of co-occurring substance use and mental health disorders:
Brain abnormalities: Brain imaging research (over 200,000 scans) has confirmed that both addiction and psychiatric conditions are rooted in brain function.
Genetics: Certain genetic traits may predispose individuals to mental health and substance use challenges.
Trauma or chronic stress: Experiencing trauma significantly increases the risk of both addiction and psychiatric illness.
Head injuries: Even mild brain trauma has been linked to increased risk of addiction, depression, anxiety, and other disorders.
Environmental toxins: Exposure to chemicals like mold, insecticides, tobacco smoke, or plastic additives can negatively affect brain health and increase the likelihood of behavioral and emotional issues.
Dementia: In older adults, sudden substance abuse or behavioral changes may point to cognitive decline or the onset of dementia.
Common Co-Occurring Mental Health Conditions
Substance abuse can accompany virtually any mental illness. However, some mental health conditions are more frequently seen in dual diagnosis cases:
ADD/ADHD: Individuals with untreated ADD/ADHD have a significantly higher risk of substance abuse. Studies show that half of those with ADHD will develop an addiction if the condition goes untreated. Early-onset ADHD can also lead to more severe and earlier drug abuse.
Anxiety Disorders: Research from the National Institute on Drug Abuse shows that people with anxiety are twice as likely to misuse drugs or alcohol.
Depression: Individuals with depression are nearly twice as likely to struggle with substance use. Many use alcohol to self-medicate, but alcohol can worsen depressive symptoms.
Post-Traumatic Stress Disorder (PTSD): Over 50% of people with PTSD also meet criteria for substance use disorder.
Bipolar Disorder: Substance use is often a coping mechanism for mood instability. Additionally, drug abuse may alter brain chemistry in ways that contribute to the onset of bipolar disorder.
Schizophrenia: Around half of all people diagnosed with schizophrenia have reported substance abuse. Drugs like marijuana may worsen schizophrenia symptoms.
Psychosis: Use of substances, especially marijuana, has been associated with an increased risk of psychotic symptoms and episodes.