Dual Diagnosis: Mental Health and Substance Abuse Disorders

Naomi Carr
Dr. David Miles
Written by Naomi Carr on 29 October 2024
Medically reviewed by Dr. David Miles on 25 November 2024

A person who experiences substance use issues and mental health issues concurrently may receive a dual diagnosis. Co-occurring mental health and substance use issues are common and can lead to more challenging and complex treatment needs, often requiring specialist intervention and long-term care.

Key takeaways:
  • Dual diagnosis, or co-occurring disorders, is used to identify a mental health condition and substance use disorder occurring simultaneously.
  • Dual diagnosis can occur due to various risk factors and causes, including genetics, environment, or traumatic experiences. Also, mental illness and substance abuse are likely to exacerbate one another.
  • The most common mental health conditions to occur alongside substance use disorders include depression, anxiety disorders, PTSD, and bipolar disorder.
a photo of a person with two mirror images to show an experience of both substance use and mental health issues

What is dual diagnosis?

Dual diagnosis is the term used when an individual concurrently experiences a substance use disorder, involving dependence or addiction to alcohol or drugs, and a mental health disorder, such as depression, anxiety, or post-traumatic stress disorder (PTSD).

Dual diagnosis, also referred to as co-occurring disorders, is very common. Reportedly around half of all people with a severe mental health disorder, such as bipolar disorder and schizophrenia, have substance abuse issues.

Often, symptoms associated with substance abuse or mental health issues can overlap and impact the other. This can mean that these disorders are often worsened by one another, affecting many areas of a person’s life, and resulting in challenging and complex treatment needs.

The relationship between mental health and substance abuse

Some people may be more likely to experience dual diagnosis than others, as the risk factors for the development of mental health issues and substance use disorders often overlap. For example, people with severe mental health and trauma-related conditions are more likely to experience dual diagnosis. Genetics and environmental factors can also impact this risk.

People who experience trauma or mental illness from a young age are found to be more likely to misuse substances later in life. This suggests that mental illness in youth can increase the risk of substance use disorders. Reasons for this may include shared risk factors, along with the use of substances as a coping strategy to escape from difficult experiences or as self-medication.

Also, studies suggest that those with substance use disorders are more likely to experience mental health symptoms than those who do not. This indicates that substance use can increase the risk of poor mental health. This risk might be increased by the impact of substances on social, professional, and personal functioning, brain chemistry, and lifestyle.

As such, there is clear evidence to suggest that mental illness and substance abuse are closely linked, with symptoms and risk factors typically overlapping. Dual-diagnosis conditions often impact and worsen one another, despite not necessarily being a direct cause of one another.

How does addiction affect mental health?

People experiencing a mental health condition are likely to find that substance abuse significantly worsens their symptoms and can make treatment more challenging. For example, addiction and associated behaviors can exacerbate mental health issues by:

  • Contributing to issues within social relationships, such as distrust from loved ones, isolation from others, or aggression or violence toward others
  • Impairing the ability to seek professional help due to fear of stigma associated with substance use or unwillingness to reduce or stop using substances to engage in treatment
  • Increased stress
  • Impacted dopamine due to substance use, causing increased feelings of anhedonia (inability to feel joy or pleasure) and dysphoria
  • Issues with finances, careers, housing, or law enforcement
  • Increased risks of physical illness

These issues can contribute to worsening mental health symptoms, which may in turn lead to an increased desire to use substances to cope with difficulties.

Recognizing co-occurring disorders: Signs and symptoms

Identifying a dual diagnosis can be challenging due to the overlapping signs and symptoms. This can make it challenging to recognize whether symptoms are caused by substance use, mental health conditions, or both. Additionally, symptoms can vary depending on the individual, the specific types of mental health issues experienced, and the type of substance being used.

For example, someone with schizophrenia and alcohol use disorder will present very differently from someone with depression and stimulant use disorder. As such, diagnosing these conditions often requires a specialized and extensive assessment of the individual.

During the assessment process, professionals may attempt to ascertain individual aspects such as:

  • History of substance use, including the amount and duration of substance use and the types of substances used
  • Family history of mental health
  • Personal mental health history
  • Current symptoms, mental state, and lifestyle

This information might guide the diagnostic process, helping to understand if mental health symptoms are caused solely by substance use or if they also occur when the individual is sober, and how symptoms are impacted by intoxication.

Additionally, understanding the individual’s substance use behaviors can help determine the presence of mental health issues. For example, whether they use substances to change, control, or mask their emotions and thoughts.

Mental health conditions that often co-occur with substance use

The most common mental health conditions that are present within a dual diagnosis include:

  • Depression: Symptoms such as low mood, loss of interest in hobbies, severe fatigue, changes in sleep and appetite, hopelessness, and thoughts of self-harm.
  • Anxiety disorders: Symptoms such as feelings of fear or dread, restlessness, agitation, persistent worrying, racing heart, sweating, shaking, stomach issues, and sleeping difficulties.
  • PTSD: Can include symptoms such as flashbacks or reliving of traumatic events, nightmares, intrusive thoughts, mood changes, severe anxiety and fear, and sleep disturbances.
  • Bipolar disorder: Periods of extreme highs or elation, known as mania, which often involve impulsive, reckless, or unpredictable behaviors, followed by periods of extreme lows or depression.
  • Borderline personality disorder: Symptoms include emotional dysregulation, extreme mood changes, poor self-image, impulsive or dangerous behaviors, abandonment fears, and relationship difficulties.
  • Dissociative disorders: Can include memory loss, personality changes, low mood, and feelings of being detached from the self, environment, or reality.
  • Schizophrenia: Can include symptoms such as hallucinations, delusions, disordered thinking, severe low mood, and cognitive issues.

Signs of substance abuse

Signs of substance abuse can vary from person to person and can also be indicators of other issues. Some of the most common signs that someone is misusing substances can include:

  • Sudden and extreme changes in behavior and mood
  • Aggression
  • Persistent fatigue
  • Changes in hobbies and social circles
  • Low mood
  • Paranoia
  • Anxiety
  • Engaging in unlawful behaviors
  • Changes in appearance, such as significant weight changes or looking unkempt
  • Very large or very small pupils
  • Poor physical hygiene
  • Increasing difficulties with academic or professional responsibilities
  • Financial issues

These signs can be linked to mental health issues or other personal difficulties and may not always be a clear indicator of substance abuse. However, recognizing these signs in a loved one can help to identify substance use issues.

Dual diagnosis treatment: Addressing both mental health and addiction

Treating dual diagnosis can be complex and will vary significantly depending on the individual, the mental health condition, and the type of substance used. A range of treatment approaches can be used to meet the individual’s needs. This will typically require specialist involvement to treat both mental health and addiction simultaneously, known as integrated treatment.

This might include:

  • Medications: Medications can be used to treat mental health conditions, withdrawal symptoms, detoxification, and physical health issues contributing to mental health and substance use issues.
  • Group therapies: Support groups and group therapies can be a beneficial treatment for people with dual diagnosis, to help understand and discuss challenges, improve community and social involvement, and receive peer support.
  • Lifestyle changes: Lifestyle changes, such as changes to diet, exercise, social circles, environment, and hobbies, can help make significant improvements to those with dual diagnosis.

Recovery and long-term care for dual diagnosis

Treatment for mental health issues and substance use disorders is often ongoing and extensive, as this can help with continuing to make improvements and changes to physical and mental well-being, helping to prevent relapse.

Long-term integrated care for dual diagnosis can be crucial to recovery, particularly the involvement of support systems, such as groups, family, and friends. This can help the individual feel accountable to others for their continued recovery, feel supported by others, and continue to create and work toward personal goals.

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Resources:

  1. National Library of Medicine. (Updated 2023). Dual Diagnosis. Medline Plus. Retrieved from
  2. Drake, R.E. (2007). Dual Diagnosis. Psychiatry, 6(9), 381-384.Retrieved from
  3. Greenstein, L. (2017). Understanding Dual Diagnosis. National Alliance on Mental Illness. Retrieved from
  4. National Institute on Drug Abuse. (2020). Common Comorbidities with Substance Use Disorders Research Report. Bethesda, MD: National Institutes on Drug Abuse. Retrieved from
  5. O'Neil, K.A., Conner, B.T., & Kendall, P.C. (2011). Internalizing Disorders and Substance Use Disorders in Youth: Comorbidity, Risk, Temporal Order, and Implications for Intervention. Clinical Psychology Review, 31(1), 104–112. Retrieved from
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  8. American Addiction Centers. (2024). Signs of Drug Use & Addiction: How To Tell if Someone is on Drugs. Retrieved from

Activity History - Last updated: 25 November 2024, Published date:


Reviewer

David is a seasoned Pharmacist, natural medicines expert, medical reviewer, and pastor. Earning his Doctorate from the Medical University of South Carolina, David received clinical training at several major hospital systems and has worked for various pharmacy chains over the years. His focus and passion has always been taking care of his patients by getting accurate information and thorough education to those who need it most. His motto: "Good Information = Good Outcomes".

Activity History - Medically Reviewed on 28 September 2024 and last checked on 25 November 2024

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