Tests and diagnosis

By Mayo Clinic Staff

These exams and tests can help rule out other problems that could be causing your symptoms, pinpoint a diagnosis and check for any related complications:

  • Physical exam. Your doctor may do a physical exam and ask in-depth questions about your health. In some cases, depression may be linked to an underlying physical health problem.
  • Lab 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 asks about your symptoms, thoughts, feelings and behavior patterns. Your doctor may have you fill out a questionnaire to help answer these questions.

Diagnostic criteria for depression

To be diagnosed with major depression, you must meet the symptom criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association. This manual is used by mental health providers to diagnose mental conditions and by insurance companies to reimburse for treatment.

For major depression, you must have five or more of the following symptoms over a two-week period, most of the day, nearly every day. At least one of the symptoms must be either a depressed mood or a loss of interest or pleasure. Other symptoms may include:

  • Depressed mood, such as feeling sad, empty or tearful (in children and teens, depressed mood can appear as constant irritability)
  • Significantly diminished interest or feeling no pleasure in all — or almost all — activities
  • Significant weight loss when not dieting, weight gain, or decrease or increase in appetite (in children, failure to gain weight as expected)
  • Insomnia or increased desire to sleep
  • Either restlessness or slowed behavior that can be observed by others
  • Fatigue or loss of energy
  • Feelings of worthlessness, or excessive or inappropriate guilt
  • Trouble making decisions, or trouble thinking or concentrating
  • Recurrent thoughts of death or suicide, or a suicide attempt

Your 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 can be based on your own feelings or may be based on the observations of someone else.

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 appropriate treatment. Your doctor or mental health provider's evaluation will help determine if your symptoms of depression are caused by a specific type of depression or another condition, such as:

  • 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 mood disorder is characterized by mood swings that range from highs to lows. It's sometimes difficult to distinguish between bipolar disorder and depression.
  • Cyclothymic disorder. Cyclothymic (sy-kloe-THIE-mik) disorder involves highs and lows that are milder than those of bipolar disorder.
  • Persistent depressive disorder. Sometimes called dysthymia (dis-THIE-me-uh), this is a less severe but more chronic form of depression. While it's usually not disabling, persistent depressive disorder can prevent you from functioning normally in your daily routine and from living life to its fullest.
  • Premenstrual dysphoric disorder. This involves depression symptoms associated with hormone changes that begin a week before and improve within a few days after the onset of your period, and are minimal or gone after completion of your period.
  • Attention-deficit/hyperactivity disorder (ADHD). Children with ADHD can demonstrate irritability without sadness or loss of interest. However, major depression can occur with ADHD.

Make sure you understand what type of depression you have so that you can learn more about your specific situation and treatment options.

Feb. 21, 2014