Mental health and substance abuse disorders affect people from all walks of life and all age groups. These illnesses are common, recurrent, and often serious, but they are treatable and many people do recover. Mental disorders involve changes in thinking, mood, and/or behavior. These disorders can affect how we relate to others and make choices. Reaching a level that can be formally diagnosed often depends on a reduction in a person’s ability to function as a result of the disorder. For example:

• Serious mental illness is defined by someone over 18 having (within the past year) a diagnosable mental, behavior, or emotional disorder that causes serious functional impairment that substantially interferes with or limits one or more major life activities.
• For people under the age of 18, the term “Serious Emotional Disturbance” refers to a diagnosable mental, behavioral, or emotional disorder in the past year, which resulted in functional impairment that substantially interferes with or limits the child’s role or functioning in family, school, or community activities.
• Substance use disorders occur when the recurrent use of alcohol and/or drugs causes clinically significant impairment, including health problems, disability, and failure to meet major responsibilities at work, school, or home.