Dual Diagnosis Capability

There are two resources available to help service organizations assess their capability (or capacity) to provide treatment to people diagnosed with co-occurring substance use disorders and mental disorders and to develop and implement a plan to do so with increasing capacity over time. These tools are known as:

  • Dual Diagnosis Capability in Addiction Treatment (DDCAT) Index
  • Dual Diagnosis Capability in Mental Health Treatment (DDCMHT) Index


The DDCAT and DDCMHT indexes are comprised of 35 items that explore an organization's policies, clinical practices, and workforce capacities (e.g., staff education, training, licensure, experience, availability). These items are organized into seven domains that include:

  • Program structure
  • Program milieu
  • Clinical practice/assessment
  • Clinical practice/treatment
  • Continuity of care
  • Staffing
  • Training


Service organizations interested in an assessment of their dual-diagnosis capabilities collaborate with program consultants, evaluators, or other providers of technical assistance who are external to their organizations. The consultants use the DDCAT and DDCMHT indexes to gather data during site visits, using methods such as:

  • Observations of service-team meetings, administrative meetings, clinical interactions
  • Interviews with administrators, program managers, team leaders, direct-service providers, consumers
  • Reviews of materials, such as organization policy manuals, clinical charts, educational materials for consumers

A Continuum of Capability

Consultants review and score the data they have collected with the indexes and categorize the organization along a continuum of capability. The continuum for addiction-service organizations assessed with the DDCAT index includes:

  • Addiction-only services (AOS)
  • Dual-diagnosis capable (DDC)
  • Dual-diagnosis enhanced (DDE)

The continuum for mental health service organizations assessed with the DDCMHT index includes:

  • Mental health-only services (MHOS)
  • Dual-diagnosis capable (DDC)
  • Dual-diagnosis enhanced (DDE)

Resources and Tools

The Center for Evidence-Based Practices has developed a number of resources to help with the implementation of Dual Disorder Capability, including CEBP-produced materials like posters, indexes, and toolkits, as well as articles, websites, books and recommendations for further reading.

Explore all of our resources