Symptoms:

Depression can change the way teenagers see themselves, their lives, and the people around them. Teenagers who are depressed usually see everything more negatively. They can't imagine that any problem or situation can be solved in a positive way.

Some or all of these symptoms of depression may be present:

• Appetite changes (usually a loss of appetite but sometimes an increase)
• Difficulty concentrating
• Difficulty making decisions
• Episodes of memory loss
• Fatigue
• Feeling upset, restless, and irritable
• Feeling worthless, hopeless, sad, or self-hatred
• Loss of interest or pleasure in activities that were once fun
• Thinking or talking about suicide or death
• Trouble sleeping, too much sleeping, or daytime sleepiness

Sometimes a person's behavior may change, or there may be problems at home or school without any symptoms of depression:

• Acting-out behaviors (missing curfews, unusual defiance)
• Criminal behavior (such as shoplifting)
• Irresponsible behavior
• Poor school performance, grades dropping
• Pulling away from family and friends, spending more time alone
• Use of alcohol or other illegal substances

If these symptoms last for at least 2 weeks and affect your mood or ability to function, get treatment.

Suicide is a risk for all teenagers with depression. See: Suicide and suicidal behavior for more information on how to recognize and treat suicidal feelings.

Signs and tests:

True depression in teens is often difficult to diagnose, because normal teenagers have up and down moods. These moods may go back and forth over a period of hours or days.

Sometimes when children or adolescents are asked, they will say that they aren't happy or sad. Health care providers should always ask children or adolescents about symptoms of depression.

The health care provider will perform a physical examination and order blood tests to rule out medical causes for the symptoms. The doctor will also check for signs of substance abuse. The following can cause, or occur because of depression:

• Heavy drinking
• Regular marijuana (pot) smoking
• Other drug use

The health care provider will also check:

• The patient's history of sadness, irritability, and loss of interest and pleasure in normal activities
• Signs of other mental health problems, such as anxiety, mania, or schizophrenia
• Risks of suicide or homicide -- whether the teen is a danger to him or herself or others

Information from family members or teachers can often help identify depression in teenagers.