Co-Occurring Disorders

Formerly known as dual diagnosis or dual disorder, co-occurring disorders describe the presence of two or more disorders at the same time. For example, a person may suffer substance abuse as well as bipolar disorder.


Just as the field of treatment for substance use and mental disorders has evolved to become more precise, so too has the terminology used to describe people with both substance use and mental disorders. The term co-occurring disorders replaces the terms dual disorder or dual diagnosis. These latter terms, though used commonly to refer to the combination of substance use and mental disorders, are confusing in that they also refer to other combinations of disorders (such as mental disorders and mental retardation).

Furthermore, the terms suggest that there are only two disorders occurring at the same time, when in fact there may be more. Clients with co-occurring disorders (COD) 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 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.

Although co-occurring disorder is the most current term used professionally, for the purposes of this article, dual disorders will be used interchangeably.

The acronym MICA, which represents the phrase Mentally Ill Chemical Abusers, is occasionally used to designate people who have a COD and a markedly severe and persistent mental disorder such as schizophrenia or bipolar disorder. A preferred definition is mentally ill chemically affected people, since the word affected better describes their condition and is not pejorative. Other acronyms include: MISA (mentally ill substance abusers), CAMI (chemical abuse and mental illness), SAMI (substance abuse and mental illness), MISU (mentally ill substance using), MICD (mentally ill chemically dependent) and ICOPSD (individuals with co-occurring psychiatric and substance disorders).

Common examples of co-occurring disorders include the combinations of major depression with cocaine addiction, alcohol addiction with panic disorder, alcoholism and polydrug addiction with schizophrenia, and borderline personality disorder with episodic polydrug abuse. Although the focus of this is on dual disorders, some patients have more than two disorders. The principles that apply to dual disorders generally apply also to multiple disorders.

The combinations of COD problems and psychiatric disorders vary along important dimensions, such as severity, chronicity, disability, and degree of impairment in functioning. For example, the two disorders may each be severe or mild, or one may be more severe than the other. Indeed, the severity of both disorders may change over time. Levels of disability and impairment in functioning may also vary.

Thus, there is no single combination of dual disorders; in fact, there is great variability among them. However, patients with similar combinations of dual disorders are often encountered in certain treatment settings.

More than half of all adults with severe mental illness are further impaired by substance use disorders (abuse or dependence related to alcohol or other drugs).

Compared to patients who have a mental health disorder or a COD use problem alone, patients with dual disorders often experience more severe and chronic medical, social, and emotional problems. Because they have two disorders, they are vulnerable to both COD relapse and a worsening of the psychiatric disorder. Further, addiction relapse often leads to psychiatric decompensation, and worsening of psychiatric problems often leads to addiction relapse. Thus, relapse prevention must be specially designed for patients with dual disorders. Compared with patients who have a single disorder, patients with dual disorders often require longer treatment, have more crises, and progress more gradually in treatment.

Psychiatric disorders most prevalent among dually diagnosed patients include mood disorders, anxiety disorders, personality disorders, and psychotic disorders.


The symptoms of co-occurring disorder include those associated with substance abuse along with those of psychiatric disorders mentioned previously.

Substance abuse is a maladaptive pattern of substance use manifested by recurrent and significant adverse consequences related to the repeated use of substances. 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.

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.

People with dual disorders are at high risk for many additional problems such as symptomatic relapses, hospitalizations, financial problems, social isolation, family problems, homelessness, suicide, violence, sexual and physical victimization, incarceration, serious medical illnesses, such as HIV and hepatitis B and C, and early death. Any one of these problems complicates the treatment of co-occurring disorder.


The common wisdom among mental health and medical professionals is that both disorders are biologically based and related to the brain. Sometimes the mental problem occurs first. This can lead people to use alcohol or drugs that make them feel better temporarily. Sometimes the substance abuse occurs first. Over time, that can lead to emotional and mental problems.

Mental disorders and addiction are each a dynamic process, with fluctuations in severity, rate of progression, and symptom manifestation and with differences in the speed of onset. Both disorders are greatly influenced by several factors, including genetic susceptibility, environment, and pharmacologic influences. Certain people have a high risk for these disorders (genetic risk); some situations can evoke or help to sustain these disorders (environmental risk); and some drugs are more likely than others to cause psychiatric or substance use disorder problems (pharmacologic risk).


To provide appropriate treatment for this complex diagnosis, the Substance Abuse and Mental Health Services Administration (SAMHSA) of the US Department of Health and Human Services recommends integrated treatment of people with COD based on current research that supports the efficacy of this treatment. Integrated treatment is a means of coordinating substance abuse and mental health interventions to treat the whole person more effectively in the context of a primary treatment relationship or service setting.

Integrated Dual Disorders Treatment occurs when a person receives combined treatment for mental illness and substance use from the same clinician or treatment team. It helps people develop hope, knowledge, skills, and the support they need to manage their problems and to pursue meaningful life goals. A person is receiving integrated treatment because their clinician or treatment team will do several things at the same time, including:

  • Help the person think about the role that alcohol and other drugs play in their life. This should be done confidentially, without any negative consequences. People feel free to discuss these issues when the discussion is confidential, nonjudgmental, and not tied to legal consequences.
  • Offer the person a chance to learn more about alcohol and drugs, to learn about how they interact with mental illnesses and with medications, and to discuss their own use of alcohol and drugs.
  • Help the person become involved with supported employment and other services that may help the process of recovery.
  • Help the person identify and develop recovery goals. If the person decides that the use of alcohol or drugs may be a problem, a counselor trained in integrated dual disorders treatment can help the person identify and develop personalized recovery goals. This process includes learning about steps toward recovery from both illnesses.
  • Provide special counseling specifically designed for people with dual disorders. If the person decides that the use of alcohol or drugs may be a problem, a trained counselor can provide special counseling specifically designed for people with dual disorders. This can be done individually, with a group of peers, with family members, or with a combination of these.

Successful strategies with important implications for clients with COD include interventions based on addiction work in contingency management, cognitive-behavioral therapy (CBT), relapse prevention, and motivational interviewing.

The Mental Health System

Most states have an assortment of public mental health centers that have a wide range of services. Mental health services are provided by a variety of mental health professionals including psychiatrists; psychologists; clinical social workers; clinical nurse specialists; certified substance abuse counselors (CSACs); other therapists and counselors including marriage, family, and child counselors; and paraprofessionals.

These mental health personnel work in a variety of settings, using a variety of theories about the treatment of specific psychiatric disorders. Different types of mental health professionals (for example, social workers and MFCCs) have differing perspectives; moreover, practitioners within a given group often use different approaches.

A major strength of the mental health system is the comprehensive array of services offered, including counseling, case management, partial hospitalization, inpatient treatment, vocational rehabilitation, and a variety of residential programs. The mental health system has a relatively large variety of treatment settings. These settings are designed to provide treatment services for patients with acute, subacute, and long-term symptoms. Acute services are provided by personnel in emergency rooms and hospital units of several types and by crisis—line personnel, outreach teams, and mental health law commitment specialists. Hospitals, day treatment programs, mental health center programs, and several types of individual practitioners provide sub-acute. Long-term settings include mental health centers, residential units, and practitioners' offices. Clinicians vary with regard to academic degrees, styles, expertise, and training.

The Addiction Treatment System

Individuals with COD are found in all addiction treatment settings, at every level of care. Although some of these individuals have serious mental illness and/or are unstable or disabled, many of them have relatively stable disorders of mild to moderate severity. As substance abuse treatment programs serve the increasing number of clients with COD, the essential program elements required to meet their needs must be defined clearly and set in place.

Essential components of treatment for substance abuse agencies with COD clients:

  1. Screening, assessment, and referral
  2. Mental and physical health consultation
  3. The use of a prescribing onsite psychiatrist
  4. Medication and medication monitoring
  5. Psychoeducational classes
  6. Onsite double trouble groups
  7. Offsite dual recovery mutual self-help groups. These elements are applicable in both residential and outpatient programs.

Screening, Assessment, and Referral

All substance abuse treatment programs should have in place appropriate procedures for screening, assessing, and referring clients with COD. It is the responsibility of each provider to identify clients with both mental—and substance—use disorders, and assure that they have access to the care needed for each disorder.

Screening is a formal process of testing to determine whether a client does or does not warrant further attention at the current time in regard to a particular disorder and, in this context, the possibility of a co-occurring substance use or mental disorder. The screening process for COD seeks to answer a "yes" or "no" question: Does the substance abuse (or mental health) client being screened show signs of a possible mental health (or substance abuse) problem?

Assessment is a process for defining the nature of that problem and developing specific treatment recommendations for addressing the problem. A basic assessment consists of gathering key information and engaging in a process with the client that enables the counselor to understand the client's readiness for change, problem areas, COD diagnoses, disabilities, and strengths. This typically involves a clinical examination of the functioning and well-being of the client and includes a number of tests and written and oral exercises. The COD diagnosis is established by referral to a psychiatrist, clinical psychologist, or other qualified healthcare professional. Assessment of the client with COD is an ongoing process that should be repeated over time to capture the changing nature of the client's status.

Some intake information includes:

  • Background: family, trauma history, history of domestic violence (either as a batterer or as a battered person), marital status, legal involvement and financial situation, health, education, housing status, strengths and resources, and employment.
  • Substance use: age of first use, primary drugs used (including alcohol, patterns of drug use, and treatment episodes), and family history of substance use problems.
  • Mental health problems: family history of mental health problems, client history of mental health problems including diagnosis, hospitalization and other treatment, current symptoms and mental status, medications, and medication adherence.

A comprehensive assessment serves as the basis for an individualized treatment plan. Appropriate treatment plans and treatment interventions can be quite complex, depending on what might be discovered in each domain. This leads to another fundamental principle: There is no single, correct intervention or program for individuals with COD. Rather, the appropriate treatment plan must be matched to individual needs according to these multiple considerations.

Mental and Physical Health Consultation

A physical and mental health consultation serves individuals with COD by determining the physical and mental health challenges and incorporates the necessary treatment(s) into patient services.

Prescribing an Onsite Psychiatrist

An onsite addiction treatment psychiatrist can improve treatment retention and decrease substance use among patients. The onsite psychiatrist brings diagnostic, medication, and psychiatric counseling services directly to the location clients are based at for the major part of their treatment. This approach often is the most effective way to overcome barriers presented by offsite referral, including distance and travel limitations, the inconvenience of enrolling in another agency and of the separation of clinical services (more "red tape"), fears of being seen as "mentally ill" (if referred to a mental health agency), cost, and the difficulty of becoming comfortable with different staff.

Medication and Medication Monitoring

Many clients with COD require medication to control their psychiatric symptoms and to stabilize their psychiatric status.

Pharmacological advances over the past decade have produced antipsychotic, antidepressant, anticonvulsant, and other medications with greater effectiveness and fewer side effects. With the support available from better medication regimens, many people who once would have been too unstable for substance abuse treatment, or institutionalized with a poor prognosis, have been able to lead more functional lives.

Psychoeducational Classes

Psychoeducational classes on mental and substance use disorders are important elements in basic COD programs. These classes typically focus on the signs and symptoms of mental disorders, medication, and the effects of mental disorders on substance abuse problems. Psychoeducational classes of this kind increase client awareness of their specific problems and do so in a safe and positive context.

Relapse prevention education presents strategies designed to help clients become aware of cues or "triggers" that make them more likely to abuse substances and help them develop alternative coping responses to those cues. Some providers suggest the use of "mood logs" that clients can use to increase their consciousness of the situational factors that underlie the urge to use or drink.

Onsite Double Trouble Groups

Onsite groups such as "Double Trouble" provide a forum for discussion of the interrelated problems of mental disorders and substance abuse, helping participants to identify triggers for relapse. Clients describe their psychiatric symptoms (such as hearing voices) and their urges to use drugs. They are encouraged to discuss, rather than to act on, these impulses. Double Trouble groups also can be used to monitor medication adherence, psychiatric symptoms, substance use, and adherence to scheduled activities. Double Trouble provides a constant framework for assessment, analysis, and planning. Through participation, the individual with COD develops perspective on the interrelated nature of mental disorders and substance abuse and becomes better able to view his or her behavior within this framework.

Dual Recovery Mutual Self-Help Groups (Offsite)

These offsite self-help groups exist in many communities. Substance abuse treatment programs can refer clients to dual recovery mutual self-help groups, which are tailored to the special needs of a variety of people with COD. These groups provide a safe forum for discussion about medication, mental health, and substance abuse issues in an understanding, supportive environment wherein coping skills can be shared.

The dual recovery mutual self-help movement is emerging from two cultures: the 12-Step fellowship recovery movement and, more recently, the culture of the mental health consumer movement. In keeping with traditional 12-Step principles and traditions, dual recovery 12-Step fellowships do not provide specific clinical or counseling interventions, classes on psychiatric symptoms, or any services similar to case management. Dual recovery fellowships maintain a primary purpose of members helping one another achieve and maintain dual recovery, prevent relapse, and carry the message of recovery to others who experience dual disorders. Dual recovery 12-Step members who take turns chairing their meetings are members of their fellowship as a whole.

Substance abuse groups include the 12-step program of Alcoholics Anonymous (AA); Narcotics Anonymous (NA), Cocaine Anonymous (CA), and so on, can provide needed support and encouragement for patients in treatment. More importantly, these services are widespread nationally and internationally. While self-help programs are not considered treatment per se, they are integral adjuncts to professional treatment services.

Outpatient Substance Abuse Treatment Programs for Clients with COD

Treatment for substance abuse occurs most frequently in outpatient settings—a term that includes a wide variety of disparate programs. Some offer several hours of treatment each week, which can include mental health and other support services as well as individual and group counseling for substance abuse; others provide minimal services, such as only one or two brief sessions to give clients information and refer them elsewhere. Some agencies offer intensive outpatient programs that provide services several hours per day and several days per week. Typically, treatment includes individual and group counseling, with referrals to appropriate community services.

Screening and assessment are used to make two essential decisions—about the stability of the individual with COD to remain in an inpatient, outpatient or appropriate alternative treatment setting and the needed mental health services. A centralized intake team is a useful approach to screening and assessment, providing a common point of entry for many clients entering treatment.

Once admitted to treatment, clients need regular reassessment as reductions in acute symptoms of mental distress and substance abuse may precipitate other changes. Periodic assessment will provide measures of client change and enable the provider to adjust service plans as the client progresses through treatment. Then careful assessment will help to identify those clients who require more secure inpatient treatment settings (such as clients who are actively suicidal or homicidal), as well as those who require 24-hour medical monitoring, those who need detoxification, and those with serious substance use disorders who may require a period of abstinence or reduced use before they can engage actively in all treatment components.

Discharge planning is important to maintain gains achieved through outpatient care. Clients with COD leaving an outpatient substance abuse treatment program have a number of continuing care options. These options include mutual self-help groups, relapse prevention groups, continued individual counseling, mental health services (especially important for people who will continue to require medication), as well as intensive case management monitoring and supports. A carefully developed discharge plan, produced in collaboration with the person with COD, will identify and match their needs with community resources, providing the supports needed to sustain the progress achieved in outpatient treatment.

Individuals with COD often need a range of services besides substance abuse treatment and mental health services. Generally, prominent needs include housing and case management services to establish access to community health and social services. These can be essential to the successful recovery of the person with COD.

It is imperative that discharge planning for the client with COD ensures continuity of psychiatric assessment and medication management, without which client stability and recovery will be severely compromised. Relapse prevention interventions after outpatient treatment need to be modified so that the client can recognize symptoms of psychiatric or substance abuse relapse on her own and can call on a learned repertoire of symptom management techniques (such as self-monitoring, reporting to a "buddy," and group monitoring). This also includes the ability to access assessment services rapidly, since the return of psychiatric symptoms can often trigger substance abuse relapse.

The Medical System

Although not substance abuse treatment settings per se, acute care and other medical settings are included here because important substance abuse and mental health treatment do occur in medical units. Acute care refers to short-term care provided in intensive care units, brief hospital stays, and emergency rooms (ERs). Providers in acute care settings usually are not concerned with treating substance use disorders beyond detoxification, stabilization, and/or referral.

In other medical settings, such as primary care offices, providers generally lack the resources to provide any kind of extensive substance abuse treatment, but may be able to provide brief interventions and treatment referrals.

Primary health-care providers (physicians and nurses) have historically been the largest single point of contact for patients seeking help with psychiatric and COD use disorders. Physicians and nurses are uniquely qualified to manage life-threatening crises and to treat medical problems related and unrelated to psychiatric and substance use disorders. And because they are in contact with such large numbers of patients, they have an exceptional opportunity to screen and identify patients with psychiatric and COD disorders. At that point, the person with COD can be referred for appropriate services in the proper setting.

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Last reviewed 12/27/2015