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Medicine LibreTexts

2.15: Mental Illness

  • Page ID
    11657
  • We have all had some exposure to mental illness, but do we really understand it or know what it is? Many of our preconceptions are incorrect. A mental illness can be defined as a health condition that changes a person’s thinking, feelings, or behavior (or all three) and that causes the person distress and difficulty in functioning. As with many diseases, mental illness is severe in some cases and mild in others. Individuals who have a mental illness don’t necessarily look like they are sick, especially if their illness is mild. Other individuals may show more explicit symptoms such as confusion, agitation, or withdrawal.

    Even if you or a family member has not experienced mental illness directly, it is very likely that you have known someone who has. Estimates are that at least one in four people is affected by mental illness either directly or indirectly.

    Consider the following statistics to get an idea of just how widespread the effects of mental illness are in society:

    • According to recent estimates, approximately 20 percent of Americans, or about one in five people over the age of 18, suffer from a diagnosable mental disorder in a given year.
    • Four of the 10 leading causes of disability—major depression, bipolar disorder, schizophrenia, and obsessive-compulsive disorder—are mental illnesses.
    • About 3 percent of the population have more than one mental illness at a time.
    • About 5 percent of adults are affected so seriously by mental illness that it interferes with their ability to function in society. These severe and persistent mental illnesses include schizophrenia, bipolar disorder, other severe forms of depression, panic disorder, and obsessive-compulsive disorder.
    • Approximately 20 percent of doctors’ appointments are related to anxiety disorders such as panic attacks. Eight million people have depression each year.
    • Two million Americans have schizophrenia disorders, and 300,000 new cases are diagnosed each year.