Tests and diagnosisBy Mayo Clinic staff
Because depression is common and often goes undiagnosed, some doctors and health care providers may ask questions about your mood and thoughts during routine medical visits. They may even ask you to fill out a brief questionnaire to help check for depression symptoms.
When doctors suspect someone has depression, they generally ask a number of questions and may do medical and psychological tests. These can help rule out other problems that could be causing your symptoms, pinpoint a diagnosis and also check for any related complications. These exams and tests generally include:
- Physical exam. This may include measuring your height and weight; checking your vital signs, such as heart rate, blood pressure and temperature; listening to your heart and lungs; and examining your abdomen.
- Laboratory tests. For example, your doctor may do a blood test called a complete blood count (CBC) or test your thyroid to make sure it's functioning properly.
- Psychological evaluation. To check for signs of depression, your doctor or mental health provider will talk to you about your thoughts, feelings and behavior patterns. He or she will ask about your symptoms, and whether you've had similar episodes in the past. You'll also discuss any thoughts you may have of suicide or self-harm. Your doctor may have you fill out a written questionnaire to help answer these questions.
Diagnostic criteria for depression
To be diagnosed with major depression, you must meet the symptom criteria spelled out in the Diagnostic and Statistical Manual of Mental Disorders (DSM). This manual is published by the American Psychiatric Association and is used by mental health providers to diagnose mental conditions and by insurance companies to reimburse for treatment.
To be diagnosed with major depression, you must have five or more of the following symptoms over a two-week period. At least one of the symptoms must be either a depressed mood or a loss of interest or pleasure. Symptoms can be based on your own feelings or may be based on the observations of someone else. They include:
- Depressed mood most of the day, nearly every day, such as feeling sad, empty or tearful (in children and adolescents, depressed mood can appear as constant irritability)
- Diminished interest or feeling no pleasure in all — or almost all — activities most of the day, nearly every day
- Significant weight loss when not dieting, weight gain, or decrease or increase in appetite nearly every day (in children, failure to gain weight as expected can be a sign of depression)
- Insomnia or increased desire to sleep nearly every day
- Either restlessness or slowed behavior that can be observed by others
- Fatigue or loss of energy nearly every day
- Feelings of worthlessness, or excessive or inappropriate guilt nearly every day
- Trouble making decisions, or trouble thinking or concentrating nearly every day
- Recurrent thoughts of death or suicide, or a suicide attempt
To be considered major depression:
- Your symptoms aren't due to a mixed episode — simultaneous mania and depression that can occur in bipolar disorder
- Symptoms must be severe enough to cause noticeable problems in day-to-day activities, such as work, school, social activities or relationships with others
- Symptoms are not due to the direct effects of something else, such as drug abuse, taking a medication or having a medical condition such as hypothyroidism
- Symptoms are not caused by grieving, such as temporary sadness after the loss of a loved one
Other conditions that cause depression symptoms
There are several other conditions with symptoms that can include depression. It's important to get an accurate diagnosis so you can get the appropriate treatment for your particular condition. Your doctor or mental health provider's evaluation will help determine if your symptoms of depression are caused by one of the following conditions:
- Adjustment disorder. An adjustment disorder is a severe emotional reaction to a difficult event in your life. It's a type of stress-related mental illness that may affect your feelings, thoughts and behavior.
- Bipolar disorder. This type of depression is characterized by mood swings that range from highs to lows. It's sometimes difficult to distinguish between bipolar disorder and depression, but it's important to get an accurate diagnosis so that you can get the proper treatment and medications.
- Cyclothymia. Cyclothymia (si-klo-THI-me-uh), also called cyclothymic disorder, is a milder form of bipolar disorder.
- Dysthymia. Dysthymia (dis-THI-me-uh) is a less severe but more chronic form of depression. While it's usually not disabling, dysthymia can prevent you from functioning normally in your daily routine and from living life to its fullest.
- Postpartum depression. This is a common type of depression that occurs in new mothers. It often occurs between two weeks and six months after delivery.
- Psychotic depression. This is severe depression accompanied by psychotic symptoms, such as delusions or hallucinations.
- Seasonal affective disorder. This type of depression is related to changes in seasons and diminished exposure to sunlight.
Make sure you understand what type of depression you have so that you can learn more about your specific situation and its treatments.
- Mood disorders. In: Diagnostic and Statistical Manual of Mental Disorders DSM-IV-TR. 4th ed. Arlington, Va.: American Psychiatric Association; 2000. http://www.psychiatryonline.com. Accessed Nov. 28, 2011.
- Depression. National Institute of Mental Health. http://www.nimh.nih.gov/health/publications/depression/complete-index.shtml. Accessed Nov. 28, 2011.
- Eisendrath SJ, et al. Psychiatric disorders. In: McPhee SJ, et al. Current Medical Diagnosis & Treatment 2012. 51st ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.com/content.aspx?aID=13381. Accessed Nov. 28, 2011.
- Depressive disorders. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/psychiatric_disorders/mood_disorders/depressive_disorders.html#top. Accessed Nov. 28, 2011.
- Krishnan R. Epidemiology, pathogenesis and neurobiology of depression. http://www.uptodate.com/home/index.html. Accessed Nov. 28, 2011.
- Practice guideline for the treatment of patients with major depressive disorder. Arlington, Va.: American Psychiatric Association. http://www.psychiatryonline.org. Accessed Nov. 28, 2011.
- Viibryd (prescribing information). St. Louis, Mo.: Forest Pharmaceuticals; 2011. http://www.frx.com/pi/viibryd_pi.pdf. Accessed Nov. 28, 2011.
- Lynch T, et al. The effect of cytochrome P450 metabolism on drug response, interactions, and adverse effects. American Family Physician. 2007;76:391.
- Katon W, et al. Initial treatment of depression in adults. http://www.uptodate.com/home/index.html. Accessed Nov. 28, 2011.
- Deligiannidis K, et al. Complementary and alternative medicine for the treatment of depressive disorders in women. Psychiatric Clinics of North America. 2010;33: 441.