Even though depression is associated with physical changes in the brain, there is no physical test for depression or other mood disorders. Depression is diagnosed by assessing a person’s mood and behavior based on reports from the person and, in the case of children, their parents, teachers and/or caregivers.

Only a medical doctor or a mental health professional such as a clinical social worker, psychologist, licensed counselor or psychiatrist can diagnose depression.

The official criteria for a diagnosis of a major depressive episode are described in the Diagnostic and Statistical Manual, 4th edition, Text Revision (DSM-IV-TR). In laymen’s terms, in order to be diagnosed as having a major depressive episode, the person must:

• Have five or more of the following symptoms nearly every day, including either or both of #1 and #2, for two weeks:
1. Depressed mood nearly every day for most of the day. In children, this may be an irritable mood.
2. Less interest or loss of pleasure in all or almost all activities.
3. Weight change in either direction of 5% of bodyweight or more when not trying to gain or lose weight. In children, failure to make expected weight gains.
4. Difficulty sleeping or sleeping too much.
5. Restless motor activity (not just feeling restless) or slowed motor activity.
6. Fatigue or loss of energy.
7. Feeling worthless or excessively guilty.
8. Difficulty thinking, concentrating or making decisions.
9. Recurring thoughts of death, thoughts of suicide (with or without a specific plan) or a suicide attempt.
• The symptoms do not meet criteria for a Mixed Episode, which is an episode of mixed ups and downs seen in people with bipolar disorder.
• The symptoms cause the person to be significantly upset or get in the way of social interactions, work or school, or other important parts of their life.
• The symptoms are not caused by drugs, alcohol or a general medical condition.
• The symptoms are not better explained by the recent death of someone the person cared about.

(MDD) is diagnosed when the person has had one or more major depressive episodes, has not had a manic or hypomanic episode, and the symptoms do not appear to be associated with another mental illness such as schizophrenia.

Bipolar disorder is diagnosed when MDD occurs in someone who also has had symptoms of mania or hypomania (e.g. excessive energy, feelings of elation, compulsive spending or sexual behavior).

Dysthymia is a lower level depression which exists chronically. The criteria in DSM-IV for dysthymia are:

A. During most days for two years or more (one year in children), the person reports depressed mood or appears depressed to others for most of the day (in children, the mood may be irritable).
B. When depressed, the patient has two or more of:
a. decreased or increased appetite
b. decreased or increased sleep
c. Fatigue or low energy
d. Reduced self-esteem
e. Decreased concentration or problems making decisions
f. Feels hopeless or pessimistic
C. During this two-year period (one year in children), the above symptoms are never absent longer than two consecutive months.
D. During the first two years (one year in children) of this syndrome, the patient has not had a major depressive episode
E. The patient has not had any manic, hypo manic or mixed episodes.
F. The patient has never fulfilled criteria for cyclothymic disorder, an alternating low level depression and low level mania.
G. The depression does not exist only as part of a chronic mental illness that causes psychosis.
H. The symptoms are often not directly caused by a medical illness or by drugs, alcohol or medication.
I. The symptoms may cause significant problems or distress in social, work, academic, or other major areas of life.[

Testing for depression consists of getting a good history of the problem from the person and, sometimes, administering a survey or checklist of depressive symptoms. There are numerous such instruments that mental health professionals and doctors use. For children, there are also surveys and checklists for parents and teachers.

It is very important to be honest when being assessed for depression. You may feel embarrassed to admit your thoughts and feelings or the behavior or your perception of your child. Alternately, you may feel that you need to exaggerate to get the help you need. However, good treatment depends on getting an accurate picture of the symptoms, so try to be honest without embellishing.

Before making a diagnosis of depression, your doctor or mental health professional may ask you to get some blood tests or a physical exam. This is to rule out physical problems that can cause depression. These include thyroid disorders and autoimmune disorders.

Your doctor or mental health professional may also ask about the medications you take, the drugs you use and how much alcohol you drink. This is because some substances, both legal and illegal ones, can cause depressive symptoms. Again, it is very important to be honest. Many diagnosticians will meet with children and teens privately to give them the opportunity to be honest without their parents hearing their answers.

Finally, the mental health or medical professional may ask questions about times when you have not been depressed. Some of these questions may seem strange, such as, “Have you ever gone long stretches of time without needing to sleep” or “Do you ever have the feeling that you can do anything and nothing could possibly stop you.” In this instance, they are trying to determine if your depression is part of a bipolar disorder.