Mental Illness Basics

Medically Reviewed on 3/21/2022

Mental illnesses are diseases or conditions that affect how you think, feel, act, or relate to other people or to your surroundings. They are very common. Many people have had one or know someone who has.

Symptoms can range from mild to severe. They can also vary from person to person. In many cases, it makes daily life hard to handle. But when an expert diagnoses you and helps you get treatment, you can often get your life back on track.

What Causes Mental Illness?

Doctors don’t know the exact cause of most mental illnesses. A combination of things, including your genes, biology, and your life experiences, seem to be involved.

Many mental illnesses run in families. But that doesn’t mean you will have one if your mother or father did.

Some conditions involve circuits in your brain that are used in thinking, mood, and behavior. For instance, you may have too much, or not enough, activity of certain brain chemicals called “neurotransmitters” within those circuits. Brain injuries are also linked to some mental conditions.

Some mental illnesses may be triggered or worsened by psychological trauma that happens when you’re a child or teenager, such as:

  • Severe emotional, physical, or sexual abuse
  • A major loss, such as the death of a parent, early in life
  • Neglect

Major sources of stress, such as a death or divorce, problems in family relationships, job loss, school, and substance abuse, can trigger or aggravate some mental disorders in some people. But not everyone who goes through those things develops a mental illness.

It’s normal to have some grief, anger, and other emotions when you have a major setback in life. A mental illness is different from that.

What Are the Symptoms of Mental Illness?

There are many different mental illnesses, and their symptoms vary. Some common symptoms include:

Problems with thinking (like being confused, suspicious, or unusually angry or sad)

If you’ve had symptoms like these, talk to your doctor or a counselor to find out what’s going on and what would help you.

How Common Is Mental Illness?

It's more common than cancerdiabetes, or heart disease. According to the National Institute of Mental Health, about 1 in 5 U.S. adults had a mental health issue in 2014, and 1 in 25 lived with someone who had a serious condition, such as schizophrenia, bipolar disorder, or major depression.

These conditions can affect people of any age, income, educational level, race, and cultural background.

What's the Treatment?

The treatment depends on the condition. In many cases, people get one or more of these treatments:

Medication. Prescription drugs help manage the symptoms, such as depression, anxiety, or psychosis.

Psychotherapy. This may be one-on-one with a counselor. Or it may happen with a group. It may include learning different ways to respond to challenging situations.

Lifestyle change. In some cases, changing your habits makes a difference. For instance, exercise is one of the treatments for mild depression.

In some cases, treatment may also include creative therapies (such as art therapy, music therapy, or play therapy), mindfulness and meditation, and brain stimulation therapies, such as:

Electroconvulsive therapy (ECT). You’re “asleep” under general anesthesia while doctors put electrodes on specific points on your head to stimulate your brain. It’s usually used for major depression, but doctors may consider it for other conditions, especially in severe cases. Most people get it several times a week for a few weeks, and usually only if other treatments haven’t worked.

Vagus nerve stimulation, in which doctors implant a device that stimulates the vagus nerve, which relays messages to areas in the brain that are thought to affect mood and thinking. It’s approved to treat severe cases of depression that don’t respond to two or more antidepressant treatments.

Transcranial magnetic stimulation, which uses magnets (outside the body) to stimulate the brain. It’s approved to treat major depression if other treatments haven’t worked. The research on how well it works is mixed.

Some people may need day treatment or hospitalization, at least for a time, for more severe conditions.


Panic attacks are repeated attacks of fear that can last for several minutes. See Answer

What Is the Outlook for People with Mental Illness?

With early diagnosis and treatment, many people fully recover from their mental illness or can manage their symptoms.

Although some people become disabled because of a chronic or severe mental illness, many others are able to live full and productive lives. The key is to get help as soon as the symptoms start and to keep up with treatment.

WebMD Medical Reference

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Medically Reviewed on 3/21/2022
SOURCE: Medically Reviewed by Brunilda Nazario, MD on March 21, 2022

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National Alliance on Mental Illness: "Mental Health Conditions."

National Institute on Mental Health: "What Is Mental Health?"

Blake, H. Frontiers in Psychiatry, Dec. 7, 2012.

National Institute of Mental Health: "Brain Stimulation Therapies."

U.S. Department of Health and Human Services: "What Is Mental Health?" "Mental Health Myths and Facts."