Mental Illness and Substance Abuse

What Are Mental Health Disorders?

Mental health disorders are conditions that can profoundly affect thought, mood, and behavior.1,2 People with these disorders may experience severe distress and problems in their relationships, jobs, or other important areas of their lives.2

Mental health issues can range in severity.1 For example, the category of serious mental illness (SMI) includes conditions that are likely to result in significantly impaired functioning in most areas of a person’s life, while the category of any mental illness (AMI) may also include relatively more mild conditions.1,2

It’s common for people to experience an episode of mental illness at some point in their lifetimes. In fact, it is estimated that as many as 1 in 5 adults in the United States has struggled in the past year with some form of mental illness.1

What Is a Dual Diagnosis?

a person suffering from addiction and mental illness

A dual diagnosis refers to the clinical situation in which a person has both an addiction and a mental illness at the same time.3 The term ‘dual diagnosis’ is not as widely used as it once was, with the phrase ‘co-occurring disorders’ becoming increasingly common.

Comorbidity is another term used to talk about addiction and mental health disorders. Like co-occurring disorders, it means two conditions present at the same time in the same person.3 However, the concept of comorbidity emphasizes the potentially adverse interaction of the two conditions.3 For example, addiction to certain drugs can cause or worsen existing mental health issues and, conversely, a mental illness may worsen the course of an addiction.

Mental Disorders that Co-Occur with Substance Abuse

Any mental illness can co-occur with drug or alcohol abuse, but certain mental health disorders co-occur at higher rates.

Mood and anxiety disorders are especially common among people with addictions.4,5 People with mood and anxiety disorders are 2x as likely to have a substance use disorder compared to people without these disorders.5

Are Developmental Disorders Considered Mental Disorders?

Developmental disorders begin in early childhood.2 They can affect a child’s emotional state, physical growth, and intellectual abilities.2 Some developmental disorders, like autism spectrum disorder, are also diagnosed as a mental disorder.2 When we talk about co-occurring disorders, however, we are not generally talking about developmental disorders.

Why Substance Use and Other Mental Disorders Co-Occur

Substance use and mental health disorders may co-occur for several reasons. First, many of the same risk factors contribute to both conditions.3 People with these specific risk factors have higher chances of developing co-occurring disorders. For example, trauma is one experience that significantly increases the risk of developing mental health issues, such as post-traumatic stress disorder (PTSD) and addiction.3

Second, having a mental health disorder can lead people to self-medicate, which involves using drugs or alcohol to cope with their symptoms.3,4 Some people may also turn to substances to ease the side effects of their psychiatric medications.3

People with mental health disorders may also experience changes in brain activity that can enhance the rewarding effects of drugs and reduce the awareness of negative consequences, making eventual addiction development more likely.3

Lastly, in some cases, addiction can lead to the development of mental health issues. Substance use can bring on changes to brain structure and function that may be similarly involved in the development of certain mental health disorders, like anxiety, depression, bipolar disorder, and schizophrenia.3 When these changes arise, a person may be more at risk of developing a mental health disorder.

Symptoms of Co-Occurring Disorders

The clinical presentation of different co-occurring disorders will vary. The following is a short list of some of common mental illnesses (and their main symptoms) that may occur alongside addiction.


Major depressive disorder involves experiencing significantly depressed mood over the course of a 2 week timeframe, in addition to symptoms such as changes in weight, insomnia, poor concentration, low energy, loss of pleasure or interest in most activities, hopelessness, guilt, and in severe cases, suicidal thoughts.2

Generalized Anxiety Disorder (GAD)

GAD involves extreme worry for at least 6 months.2 People with GAD find that the worry is hard to control. They may also feel restless, tired, and irritable, and they may experience aches and pains, poor concentration, and sleeping problems.

Attention-Deficit/Hyperactivity Disorder (ADHD)

ADHD involves a persistent pattern of hyperactivity, impulsivity, and difficulty holding attention.2 People with this condition may find that their symptoms interfere in many areas of their lives, especially work and school.

Bipolar I Disorder

Bipolar I disorder is a mood disorder that includes severe highs and lows, known as manic and depressive episodes.2 During manic episodes, people may be irritable, easily distracted, impulsive, and unable to sleep. During depressive episodes, they may be sad, hopeless, or empty most of the day, nearly every day and may sleep too much or too little almost every day. They may also have recurrent thoughts of death or suicide.

Borderline Personality Disorder (BPD)

Personality disorders are long-standing patterns of thinking, feeling, and behaving that affect a person’s life and relationships.2 People with BPD may have very unstable self-images and may also alternate being idealizing and devaluing others, making it very difficult for them to sustain positive relationships. They may have severe mood swings, feel chronically empty, and have difficulty dealing with their anger. They may be impulsive, put themselves in dangerous situations, and self-harm to cope with their feelings.

Obsessive-Compulsive Disorder (OCD)

OCD is another type of anxiety disorder that involves obsessions and compulsions.2 Obsessions are persistent unwanted thoughts and images that a person may fixate on. Compulsions are repetitive behaviors driven by obsessions or by rigid rules the individual has defined for himself.

Post-traumatic Stress Disorder (PTSD)

PTSD can develop after a person goes through a traumatic event or sees another person experience a traumatic event.2 Symptoms of PTSD include re-experiencing the event in some form, trying to avoid reminders of the event, mood changes, and hypervigilance.


Schizophrenia is a serious mental illness that negatively affects people’s ability to care for themselves, keep up with their responsibilities, and have stable relationships.2 People with schizophrenia may experience hallucinations (hearing, seeing, or smelling things that are not really there), delusions (false beliefs that feel real), negative affect (appearing flat or emotionless), and disorganized or chaotic thoughts and behaviors.

Risks Factors for Addiction and Co-Occurring Disorders

several factors or experiences can increase the risk of co-occurring disorders

Certain factors or experiences can increase the risk of developing a substance use disorder and/or another mental health disorder:3

  • Genetics. Research suggests that somewhere around 40–60% percent of a person’s risk of developing addictions is attributable to genetic factors. Genetics can differentially affect how a person reacts to substances, how the body metabolizes certain drugs, and how an individual copes with stress.
  • Trauma. People who have had traumatic experiences may develop post-traumatic stress disorder and turn to drugs and alcohol to self-medicate certain symptoms such as anxiety.
  • Chronic stress. High levels of stress can affect activity in areas of the brain that are involved in controlling impulses and behavior. Stress may also disrupt normal dopamine signaling in the brain in a way that makes drugs feel more rewarding or pleasurable.
  • Certain drugs of abuse. People using or withdrawing from certain drugs, such as cocaine, methamphetamine, and marijuana, may experience side effects, like depression, anxiety, or psychosis.5 Using these drugs can also worsen an existing mental health condition.
  • Early drug use. Beginning to use drugs or alcohol as an adolescent increases the risk of developing both substance use disorders as well as mental illness.

Why Co-Occurring Disorders Require Specialized Treatment

People with co-occurring disorders can benefit from specialized treatment that addresses both issues at the same time. Integrative treatment is more effective than treating each condition alone.3 Studies have shown that treating only one condition can increase the risk of future relapses.4 Getting specialized treatment can ensure that you are getting the comprehensive help that you need to fully recover.

To find out whether a facility treats both conditions, ask their admissions team whether they provide treatment for co-occurring disorders. You can explain that you suffer from a mental illness and want to be sure that you receive treatment for both conditions.

The Dangers of Self-Medication

Self-medication is the act of using drugs or alcohol to cope with negative emotions or troubling symptoms.3,4 Drugs and alcohol can cause feelings of euphoria and relaxation, which people may seek out in an attempt to temporarily “numb” their emotions.

Even though self-medication can make a person feel better temporarily, it can cause more problems in the long run.4 People who self-medicate are more likely to develop a substance use disorder.3,4


Get Help for Mental Health and Drug Abuse Issues

Getting help for mental health and drug abuse issues at the same time can result in better treatment outcomes than treatment for only one condition.3 Laguna Treatment Hospital is one facility that provides comprehensive treatment for co-occurring disorders. They offer several different options to meet your needs:

  • Medical detoxification. Laguna Treatment Hospital is Orange County’s first chemical dependency recovery hospital. We offer medically supervised detoxification and utilize medications to manage withdrawal from opioids, alcohol, benzodiazepines, and other drugs of abuse. The medical detox program at Laguna also offers beds with EarlySense technology, which closely monitors your vital signs during withdrawal and alerts a member of the medical team if you show any signs of distress.
  • Residential treatment. Laguna provides a temporary live-in treatment option where people can focus on their recovery away from the demands of daily life. During a stay, residents can participate in group and individual therapy sessions, 12-step meetings, and other therapeutic activities, like yoga and meditation.
  • Partial Hospitalization Program (PHP). Once a person has completed residential treatment, there is the option to transition to PHP, which offers treatment for 5 hours a day, 6 days per week. This option allows you to continue working on your recovery in a structured environment with the opportunity to slowly integrate back into your daily life.

Laguna Treatment Hospital specializes in treating co-occurring disorders. Call now to learn more about how we can help.

Statistics on Co-Occurring Disorders

an info graphic showing co-occurring mental illness and substance use disorder

an info graphic showing percentage of past year drug users with a mental illness

an infographic showing perceived need for substance use treatment and reasons for not receiving it

an infographic showing perceived need for mental health treatment and reasons for not receiving it

an infographic showing prescription medication as a mental health treatment for co-occurring mental illness and substance use disorder


We used SAMHSA’s NSDUH data to explore the relationship between mental illness and substance use. All calculations in this analysis were done using the NSDUH 2016 public-use files. SAMHSA’s online detailed tables are based on their restricted-use files, so the estimates given here are slightly different.

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Regional Guides


  1. National Institute on Mental Health. (2019). Mental illness.
  2. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: Author.
  3. National Institute on Drug Abuse. (2018). Common comorbidities with substance use disorders.
  4. Turner, S., Mota, N., Bolton, J., & Sareen, J. (2018). Self-medication with alcohol or drugs for mood and anxiety disorders: A narrative review of the epidemiological literature. Depression and Anxiety, 35(9), 851-860.
  5. National Institute on Drug Abuse. (2017). Health consequences of drug misuse: Mental health effects.


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