Mood disorders, including major depression and bipolar disorder, are conditions that involve a person's body, mood, and thoughts. Depression can affect and disrupt eating, sleeping, or thinking patterns, and is not the same as being unhappy or in a "blue" mood, nor is it a sign of personal weakness or a condition that can be willed or wished away. Bipolar disorder, or manic-depressive illness, also includes periods of elevated mood, agitation, and increased energy. Mood disorders can be effectively treated with medication, psychotherapy, and other treatments including light treatment and brain stimulation.