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About Co-Occurring Disorders

What are Co-Occurring Disorders (COD)?

COD refers to the simultaneous existence of substance use and mental disorders. Individuals with 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 COD occurs when an individual has both mental illness and a substance use disorder. From a treatment perspective, both disorders are primary. Although the disorders may impact each other, neither is merely a sympton of the other.

What does prevalence data tell us about COD?

Prevalence and other available data convey four key findings that are important in understanding the challenges of providing effective treatment to persons with COD.

(1) COD are common in the general adult population, though many individuals with COD go untreated. The National Survey on Drug Use and Health (NSDUH) reports that in 2002, four million adults met the criteria for COD.

(2) There is an increased prevalence of people with COD and programs for people with COD. Between the years of 1997 and 1999, a study conducted by Gustafson et al. found a ten percent increase in both the number of people with COD entering treatment and the number of programs in many states.

(3) Rates of mental disorders increase as the number of substance use disorders increase, further complicating treatment. In an analysis of data from a series of studies supported by the National Institute on Drug Abuse, The Drug Abuse Treatment Outcome Study (DATOS), Flynn et al. (1996) determined that the likelihood of mental disorders rises with the increasing number of substance dependencies.

(4) Compared to people with mental or substance use disorders alone, people with COD are more likely to be hospitalized. Coffey and colleagues (2001) found that the rate of hospitalization for clients with COD was more than twenty times the rate for substance abuse-only clients and five times the rate for mental disorders-only clients.

Please refer to the Substance Abuse Treatment For Persons with Co-Occurring Disorders Treatment Improvement Protocol #42 available through the California Department of Alcohol and Drug Programs Resource Center at 1-800-879-2772 for further information.

What are the State of California and counties doing about COD?

The Governor's Budget Act of 1995-96 mandated the Departments of Alcohol and Drug Programs (ADP) and Mental Health (DMH) actively seek methods to eliminate barriers between the substance abuse and mental health treatment systems at both the state and local levels on behalf of persons with dual diagnoses of serious mental illness and substance use disorders, now called COD. From that time, ADP and DMH staff partnered with county alcohol and drug program administrators, mental health directors, representatives from non-profit organizations, consumers, and other advocates to form the Dual Diagnosis Task Force and then the Co-Occurring Work Group and the Co-Occurring Joint Action Council (COJAC) to work on integrated strategies to eliminate barriers to the provision of services for persons with COD.

The passage of Proposition 63 (now known as the Mental Health Services Act or MHSA) in November 2004 provides the opportunity for DMH to make available increased funding, personnel and other resources to support county mental health programs, including COD services, and monitor progress toward statewide goals for children, transition age youth, adults, older adults and families. The MHSA addresses six components for creating a better program of mental health services and supports in California:

  • Community Planning
  • Services and Supports
  • Capital (buildings) and Information Technology (numbers and facts)
  • Education and Training (people resources)
  • Prevention and Early Intervention
  • Innovation

The first component of the MHSA, "Community Services and Supports (CSS)" is mental health services and supports for children, youth, adults and older adults with serious mental and emotional problems. The Prevention and Early Intervention (PEI) component of the MHSA offers a unique opportunity for AOD providers to obtain funding for COD-related services for individuals not defined as "Severely Mentally Ill". For further information see Funding Opportunities.


Persons with COD are treatable. Recovery, the ability to reclaim a prior condition of wellness, is possible to lead a happier, healthier, more productive life. Individuals with COD do recover.

Aids to recovery include:

  • Education;
  • Psychosocial therapeutic interventions;
  • Medications;
  • Individual and group/peer counseling;
  • Family and peer support; and
  • Socialization activities.

Self exploration of stress-causing factors and responses coupled with family and peer support assist to overcome relapse.