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    Mental Illness Basics

    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.

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    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.


    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)

    • Keeping to themselves
    • Mood swings
    • Relationship problems
    • Hallucinations (seeing or hearing things that aren’t there)
    • Abusing alcohol or drugs
    • Feeling low on hope and not enjoying things that they used to like
    • Thoughts of suicide or harming themselves or others
    • Sleep problems (too much or too little)

    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.

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