- Depression is more than just the "blues"; it is more severe and persistent. People who are depressed can't think clearly, concentrate, or enjoy life. They may think about death. They feel worthless. Decreased or increased appetite and sleeping too little or too much are also symptoms.
- Mania is the opposite of depression. People with mania are excited, elated, hyperactive, irritable, easily distracted, and extremely talkative. They have an inflated self-esteem, a decreased need for sleep, and may go on spending sprees. As a manic episode worsens, a person can experience delusions and hallucinations, which makes such an episode similar to schizophrenia.
- Bipolar disorder is when people alternate between episodes of mania and depression.