Adult Co-Occurring Disorders

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Co-Occurring disorders refers to co-occurring substance use (abuse or dependence) and mental disorders. Clients said to have co-occurring disorders have one or more disorders relating to the use of alcohol and/or other drugs of abuse as well as one or more mental disorders.

A diagnosis of co-occurring disorders (COD) occurs when at least one disorder of each type can be established independent of the other and is not simply a cluster of symptoms resulting from the one disorder. Many may think of the typical person with COD as having a severe mental disorder combined with a severe substance use disorder, such as schizophrenia combined with alcohol dependence. However, counselors working in addiction agencies are more likely to see persons with severe addiction combined with mild to moderate severity mental disorders; an example would be a person with alcohol dependence combined with a depressive disorder or an anxiety disorder. Efforts to provide treatment that will meet the unique needs of people with COD have gained momentum over the past 2 decades in both substance abuse treatment and mental health services settings.

Substance abuse and substance dependence are two types of substance use disorders and have distinct meanings. The standard use of these terms derives from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) (American Psychiatric Association [APA] 1994). Produced by the APA and updated periodically, DSM-IV is used by the medical and mental health fields for diagnosing mental and substance use disorders. This reference provides clinicians with a common language for communicating about these disorders. The reference also establishes criteria for diagnosing specific disorders.

Substance abuse, as defined in DSM-IV-TR (4th edition, Text Revision; APA 2000), is a “maladaptive pattern of substance use manifested by recurrent and significant adverse consequences related to the repeated use of substances” (APA 2000, p. 198). Individuals who abuse substances may experience such harmful consequences of substance use as repeated failure to fulfill roles for which they are responsible, legal difficulties, or social and interpersonal problems. It is important to note that the chronic use of an illicit drug still constitutes a significant issue for treatment even when it does not meet the criteria for substance abuse.

Adapted from Substance Abuse Mental Health Services Administration, TIP 42

For individuals with more severe or disabling mental disorders, as well as for those with developmental disabilities and traumatic brain injuries, even the threshold of substance use that might be harmful (and therefore defined as abuse) may be significantly lower than for individuals without such disorders. Furthermore, the more severe the disability, the lower the amount of substance use that might be harmful.The standard use of terms for non-substance use mental disorders, like the terms for substance use disorders, derive from the DSM-IV-TR (APA 2000). These terms are used throughout the medical and mental health fields for diagnosing mental disorders. As with substance use disorders, this reference provides clinicians with a common language for communicating about these disorders. The reference also establishes criteria for diagnosing specific disorders. (See chapter 1, Figure 1-2 for an overview of the association between specific mental disorders and substance use disorders.)

Terms for Co-occurring Disorders

Many terms have been used in the field to describe the group of individuals who have COD (most of these terms do not reflect the “people-first” approach used in this TIP). Some of these terms represent an attempt to identify which problem or disorder is seen as primary or more severe. Others have developed in the literature in order to argue for setting aside funding for special services or to identify a group of clients who may benefit from certain interventions. These terms include:

  • MICA—mentally ill chemical abuser. This acronym is sometimes seen with two As (MICAA) to signify mentally ill chemically addicted or affected. There are regional differences in the meaning of this acronym. Many States use it to refer specifically to persons with serious mental disorders.
  • MISA—mentally ill substance abuser.
  • MISU—mentally ill substance using.
  • CAMI—chemically abusing mentally ill, or chemically addicted and mentally ill.
  • SAMI—substance abusing mentally ill.
  • MICD—mentally ill chemically dependent.
  • Dually diagnosed.
  • Dually disordered.
  • Comorbid disorders.
  • ICOPSD—individuals with co-occurring psychiatric and substance disorders.

While all of these terms have their uses, many have developed connotations that are not helpful or that have become too broad or varied in interpretation to be useful. For example, “dual diagnosis” also can mean having both mental and developmental disorders. Readers who hear these terms should not assume they all have the same meaning as COD and should seek to clarify the client characteristics associated with a particular term. Readers also should realize that the term “co-occurring disorder” is not inherently precise and distinctive; it also may become distorted by popular use, with other conditions becoming included within the term. The issue here is that clients/consumers may have a number of health conditions that “co-occur,” including physical health problems. Nevertheless, for the purpose of this TIP, co-occurring disorders refers to substance use disorders and mental disorders.

Some clients’ mental health problems may not fully meet the strict definition of co-occurring substance use and mental disorders criteria for diagnoses in DSM-IV categories. However, many of the relevant principles that apply to the treatment of COD also will apply to these individuals. Careful assessment and treatment planning to take each disorder into account will still be important. Suicidal ideation is an excellent example of a mental health symptom that creates a severity problem, but alone doesn’t necessarily meet criteria for a formal DSM-IV condition since suicidality is a symptom and not a diagnosis. Substance-induced suicidal ideation can produce catastrophic consequences. Some individuals may exhibit symptoms that could indicate the existence of COD but could also be transitory; for example, substance-induced mood swings, which can mimic bipolar disorder, or amphetamine-induced hallucinations or paranoia, which could mimic schizophrenia. Depending on the severity of their symptoms, these individuals also may require the full range of services needed by those who meet the strict criterion of having both conditions independently, but generally for acute periods until the substance-induced symptoms resolve.

Adapted from:
TIP 42 Substance Abuse Treatment for Persons With Co-Occurring Disorders
Substance Abuse Mental Health Services Administration (SAMHSA)

Person-Centered Terminology

In recent years, consumer advocacy groups have expressed concerns related to how clients are classified. Many take exception to terminology that seems to put them in a “box” with a label that follows them through life, that does not capture the fullness of their identities. A person with COD also may be a mother, a plumber, a pianist, a student, or a person with diabetes, to cite just a few examples. Referring to an individual as a person who has a specific disorder—a person with depression rather than “a depressive,” a person with schizophrenia rather than “a schizophrenic,” or a person who uses heroin rather than “an addict”—is more acceptable to many clients because it implies that they have many characteristics besides a stigmatized illness, and therefore that they are not defined by this illness.

More Terminology

Personality Disorders

These are the disorders most commonly seen by the addiction counselor and in quadrant III substance abuse treatment settings. Individuals with personality disorders have symptoms and personality traits that are enduring and play a major role in most, if not all, aspects of the person’s life. These individuals have personality traits that are persistent and cause impairment in social or occupational functioning or cause personal distress. Symptoms are evident in their thoughts (ways of looking at the world, thinking about self or others), emotions (appropriateness, intensity, and range), interpersonal functioning (relationships and interpersonal skills), and impulse control.
Personality disorders are listed in the DSM-IV under three distinct areas, referred to as “clusters.” The clusters are listed below with the types of symptoms or traits seen in that category. The specific personality disorders included in each cluster also are listed. For personality disorders that do not fit any of the specific disorders, the diagnosis of “personality disorder not otherwise specified” is used.

  • Cluster A: Hallmark traits of this cluster involve odd or eccentric behavior. It includes paranoid, schizoid, and schizotypal personality disorders.
  • Cluster B: Hallmark traits of this cluster involve dramatic, emotional, or erratic behavior. It includes antisocial, borderline, histrionic, and narcissistic personality disorders.
  • Cluster C: Hallmark traits of this cluster involve anxious, fearful behavior. It includes avoidant, dependent, and obsessive-compulsive personality disorders.

The prevalence of co-occurring substance abuse and antisocial personality disorder is high (Flynn et al. 1997). In fact, much of substance abuse treatment is targeted to those with antisocial personality disorders and substance abuse treatment alone has been especially effective for these disorders.

Psychotic Disorders

The common characteristics of these disorders are symptoms that center on problems of thinking. The most prominent (and problematic) symptoms are delusions or hallucinations. Delusions are false beliefs that significantly hinder a person’s ability to function. For example, a client may believe that people are trying to hurt him, or he may believe he is someone else (a CIA agent, God, etc.). Hallucinations are false perceptions in which a person sees, hears, feels, or smells things that aren’t real (i.e., visual, auditory, tactile, or olfactory).

Psychotic disorders are seen most frequently in mental health settings and, when combined with substance use disorders, the substance disorder tends to be severe. Clients with psychotic disorders constitute what commonly is referred to as the serious and persistent mentally ill population. Increasingly, individuals with serious mental illness are present in substance abuse treatment programs (Gustafson et al. 1999).

Drugs (e.g., cocaine, methamphetamine, or phencyclidine) can produce delusions and/or hallucinations secondary to drug intoxication. Furthermore, psychotic-like symptoms may persist beyond the acute intoxication period.


This is one of the most common of the psychotic disorders and one of the most destructive in terms of the effect it has on a person’s life. Symptoms may include the following: hallucinations, delusions, disorganized speech, grossly disorganized or catatonic behavior, social withdrawal, lack of interest, and poor hygiene. The disorder has several specific types depending on what other symptoms the person experiences. In the paranoid type there is a preoccupation with one or more delusions or frequent auditory hallucinations. These often are experienced as threatening to the person. In the disorganized type there is a prominence of all of the following: disorganized speech, disorganized behavior, and flat or inappropriate affect (i.e., emotional expression).

Mood Disorders

The disorders in this category include those where the primary symptom is a disturbance in mood, where there may be inappropriate, exaggerated, or a limited range of feelings or emotions. Everyone feels “down” sometimes, and everybody experiences feelings of excitement or emotional pleasure. However, when a client has a mood disorder, these feelings or emotions are experienced to the extreme. Many people with substance use disorders also have a co-occurring mood disorder and tend to use a variety of drugs in association with their mood disorder. There are several types of mood disorders, including depression, mania, and bipolar disorder.


Instead of just feeling “down,” the client might not be able to work or function at home, might feel suicidal, lose his or her appetite, and feel very tired or fatigued. Other symptoms can include loss of interest, weight changes, changes in sleep and appetite, feelings of worthlessness, loss of concentration, and recurrent thoughts of death.


This includes feelings that are more toward the opposite extreme of depression. There might be an excess of energy where sleep is not needed for days at a time. The client may be feeling “on top of the world,” and during this time, the client’s decisionmaking process might be significantly impaired and expansive and he may experience irritability and have aggressive outbursts, although he might think such outbursts are perfectly rational.
Bipolar. A person with bipolar disorder cycles between episodes of mania and depression. These episodes are characterized by a distinct period of abnormally elevated, expansive, or irritable mood. Symptoms may include inflated self-esteem or grandiosity, decreased need for sleep, being more talkative than usual, flight of ideas or a feeling that one’s thoughts are racing, distractibility, increase in goal-directed activity, excessive involvement in pleasurable activities that have a high potential for painful consequences (sexual indiscretions, buying sprees, etc.). Excessive use of alcohol is common during periods of mania.

Anxiety disorders

As with mood disorders, anxiety is something that everyone feels now and then, but anxiety disorders exist when anxiety symptoms reach the point of frequency and intensity that they cause significant impairment. In addiction treatment populations, the most common anxiety syndrome seen is that associated with early recovery, which can be a mix of substance withdrawal and learning to live without the use of drugs or alcohol. This improves with time and addiction treatment. However, other anxiety disorders that may occur, but need particular assessment and treatment, are social phobia (fear of appearing or speaking in front of groups), panic disorder (recurrent panic attacks that usually last a few hours, cause great fear, and make it hard to breathe), and posttraumatic stress disorders (which cause recurrent nightmares, anxiety, depression, and the experience of reliving the traumatic issues).