Over half of the individuals with mental health disorders also deal with substance related issues. In many cases, the combination of dug or alcohol use and mental health disorders is attributed to self-medicating behaviors. Specifically, drugs and alcohol can be in the form of self-medication, where individuals with an untreated mental illness like anxiety or depression have their symptoms temporarily relieved while using drugs or alcohol. Despite temporarily relieving symptoms of mental illness, substance abuse typically causes symptoms to increase in their severity over time (Duckworth & Freedman, 2013). Co-occurring mental illness and substance abuse are highly associated with negative treatment outcomes. Individuals with co-occurring disorders have been found to suffer from higher rates of relapse, hospitalizations, incarceration, homelessness, victimization, and poor health outcomes. Co-occurring disorders have proven to be a challenge to treat. This course will discuss co-occurring disorders, their diagnosis, and effective treatment options.