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What Are Co-occurring Disorders?

Substance dependence

Co-occurring disorders (COD), also known as dual diagnosis, is a condition in which people develop both substance dependence and psychological disorders at the same time, and vice versa. However, it's not that a patient with COD only have two disorders at the same time. They may have one or more disorders associated with the substance use and one or more conditions related to the mental health.

Some Quick Facts

  • Co-occurring disorders affect approximately 8.9 million Americans annually; however, only 7.4% of them receive proper treatment.
  • Almost 75% of substance abusers have at least one serious psychological disorder.
  • About 29% of mental health patients have a current or previous substance use problem.

How Co-occurring Disorders Occur?

Addictive substances affect the brain in many different ways. Often, they cause chemical imbalances in the brain by stimulating its reward system, increasing the level of dopamine. Dopamine is a neurotransmitter (chemical messenger that is naturally produced by the brain) located in the regions of brain that are responsible for emotion, motivation, movement, and feelings of joy.

Moreover, many drugs have similarities in chemical structures with neurotransmitters. These drugs send abnormal messages to the nervous system by fooling the brain's receptors and activating unwanted nerve cells. This abnormal activation of nerve cells eventually prevents the brain's normal recycling process by releasing the neurotransmitters abnormally.

Overall, substance abuse has a profound impact on an addict, as it alters the person's brain in fundamental ways, disrupting the normal hierarchy of desires and needs and substituting them with new priorities associated with buying and using abusive substances. As a result, the addict develops mental and emotional problems. However, substance dependence isn't always the culprit behind COD; in many cases, the opposite may happen. That means a mental health condition can also lead to COD.


Co-occurring disorders are usually diagnosed when an individual is confirmed with at least one disorder of each type (substance abuse and mental health disorders), independent of the other. That means that COD are not merely a bunch of symptoms arising as a result of one disorder. The symptoms of both the type must be detected in the suspected individual. However, it is often hard to say that which type the patient may experience first. Sometimes the mental disorder can play a significant role to lead a person in abusing alcohol or drugs, and sometimes the substance abuse problem can lead to mental disorders.

Signs and Symptoms

There are no specific signs and symptoms to diagnose COD. The signs and symptoms include those relating to both substance abuse and psychological disorders.

Common mental health disorders observed in people with COD include:

  • Schizoaffective disorder
  • Obsessive-compulsive disorder
  • Compulsive gambling
  • Attention deficit hyperactivity disorder (ADHD)
  • Manic depressive disorder
  • Anxiety
  • Depression
  • Mood disorders
  • Post-traumatic stress disorder (PTSD)
  • Emotional intensity disorder
  • Sexual and eating disorders
  • Dissocial personality disorder

In addition to the symptoms of mental health disorder and substance dependence, individuals with COD are reported to involve in a variety of associated problems, including family problems, financial crisis, social disintegration, incarceration, homelessness, sexual and physical harassment, violence, suicide, serious medical illnesses and hospitalizations.

Image source: Kaushik Narasimhan, CC-BY-2.0, via Flickr

⚠️ Disclaimer: The information provided in this article is for educational purposes only and should not be considered as medical advice. Please consult a healthcare professional for personalized advice.