General Information About Mental Illness

What is Mental Illness?

A mental illness is a disorder that causes mild to severe disturbances in thinking, perception, mood, or behavior.  If these disturbances significantly affect a person's ability to cope with life's ordinary demands and routines, then he or she should immediately seek proper treatment with a mental health professional. With the proper care and treatment, a person can recover and resume normal activities.

What Are Some Misconceptions About Mental Illness?

Common misconceptions about mental illness are that it is the result of moral failing, personal weakness, or a lack of willpower. Another is that individuals with mental illness are dangerous or violent. Such beliefs may explain why only one-third of individuals with diagnosable mental disorders seek professional help. Actually, mental disorders are real illnesses that respond to mental health treatment. Individuals with mental illnesses can effectively return to normal, productive lives if they receive appropriate treatment.

Who Develops a Mental Illness?

Mental illnesses afflict both men and women. Any person—no matter their age, economic status or race can develop a mental illness. However, individuals living in poverty are at higher risk. During any one-year period, about 20 percent of the U.S. population suffers from a diagnosable mental disorder that interferes with employment, attendance at school or other activities of daily life.

What Causes Mental Illness?

The precise cause of most mental disorders is not fully understood. In general, mental disorders result from a combination of genetic factors, other biological factors, and environmental factors. The influence between biology and environment is complicated. The brain influences behavior, and experience effects the development of the brain.

What Are Common Types of Mental Illness?

Below are brief descriptions of the three most prevalent adult mental disorders. For more detailed descriptions of these disorders, please refer to our brochures that address these disorders individually.

Mood Disorders

Depression is the most commonly diagnosed emotional problem. It is a prolonged or deep emotional feeling of sadness, being "blue," or "down." Depressive feelings such as discouragement or sadness are perfectly normal if they do not become too severe or last too long. However, if persistent or continues for long periods of time a person should seek help.

Bipolar Disorder, also known as manic-depressive illness, is a disorder that causes unusual shifts in a person's mood, energy, and ability to function. Persons with bipolar disorder have mood cycles with depression alternating with mania, and express many of the following manic symptoms:

  • Abnormal or excessive elation
  • Unusual irritability
  • Decreased need for sleep
  • Grandiose notions
  • Racing thoughts and Increased talking
  • Increased sexual desire
  • Markedly increased energy

With treatment, most people with depression and bipolar disorder can recover and return to their previous productive lives. Almost all people who experience mood disorders respond to medication, therapy or a combination of these treatments.

Anxiety Disorders

Anxiety is a feeling of tension associated with a sense of threat, danger, or severe fear. It is typical for us to have some mild tension present in our daily lives; however, heightened and prolonged anxiety is emotionally painful. It disrupts a person's daily functioning. Examples of anxiety disorders include panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder.

Therapy and/or medication are recommended for people with moderate to severe anxiety


Schizophrenia is a mental disorder that is characterized by a profound disruption in thinking, perception and emotion, and which affects about 1 percent of the U.S. population. This mental disorder can manifest itself in a variety of ways. The predominant difficulties associated with schizophrenia are related to a person's unusual or Illogical thinking (e.g. , strongly held false beliefs) or perceptions (e.g. , hearing voices or seeing things that do not actually exist). Because the person's thinking is sometimes distorted, a person with schizophrenia may have a variety of behaviors that appear odd or strange to others. In addition, the person's speech may be irrational or disjointed.

Schizophrenia can be treated through the use of medication, therapy and psychosocial rehabilitation. Thanks to new treatment options, many individuals with schizophrenia are able to work, live with their families, and enjoy friends.

What Treatments Are Available?

Effective treatment will start with a thorough evaluation. The family doctor or a mental health specialist will assess any medical and psychological condition then make an appropriate referral.

Mental illnesses are treatable through medication, therapy, and rehabilitative services. In fact, there is a range of treatments that can meet any individual's mental health needs. To understand more about mental health services in your county, please read our brochure,  "Adult Mental Health Services."

How Can I Get Help?

If you or your family member needs mental health services, consult your family doctor and ask for a mental health evaluation and treatment for yourself or your family member.

You and your family member may be eligible to receive mental health services from the County Mental Health Plan. The County has a toll free number available 24 hours a day, which is staffed with mental health specialists who can assess your needs and make appropriate referrals. They will be able to talk with you in your preferred language. Their services and phone numbers are listed in the county government pages of your local phone book.

Where Can I Get More Information?

National Institute of Mental Health
(888) 826-9438

National Mental Health Association
(800) 969-6642

National Alliance for the Mentally Ill