Having a simplified though medically accurate definition of chronic pain and depression can be helpful for people who need to accurately explain how they feel to their doctor.

What is chronic pain?

To understand chronic pain we must first define acute pain. Acute pain is the kind of pain experienced when a person cuts his or her finger or gets the stomach flu. It is associated with tissue damage, inflammation, or a disease process, and its duration is relatively brief—it is consistent with expected healing time, going away as the body recovers and heals. Acute pain is typically not associated with clinical depression.

In contrast, chronic pain may last weeks, months, or even years. Chronic pain is often divided into two types:

  1. Chronic pain that has a discernible cause and is often associated with a progressive disease such as osteoarthritis or cancer. In these cases, the disease dictates special evaluation and approaches to pain treatment.

    See Osteoarthritis Symptoms and Signs

  2. Chronic pain for which the exact cause cannot be identified. In these cases, either the specific disease process or pain generator cannot be identified or a cause of pain exists but does not account for the level of pain and suffering being reported by the patient. This type of chronic pain may be referred to as chronic benign pain, chronic non-cancer pain, and chronic non-specific pain.

This second type of chronic pain often starts off as acute pain but is redefined as chronic pain if it does not go away on a typical timeline—for example, an injury may physically heal but still cause pain. The body’s nervous system delivers messages of pain to the brain even though no tissues are being damaged. Chronic pain establishes a well-worn pathway in the nervous system, meaning that pain is easily triggered, sometimes even in the absence of an underlying anatomical problem.


What is depression?

The type of depression discussed in this article goes beyond the normal sadness that is occasionally experienced by everyone as part of everyday life. People may refer to diagnosed depression as major depression, major depressive disorder, or clinical depression. No matter what it is called, experts agree that depression is more than just feeling sad or blue for a few days. The gold-standard definition for a major depressive episode comes from the Diagnostic and Statistical Manual (DSM) developed by the American Psychiatric Association.

According to the DSM-5 (2013), symptoms of a major depression occur daily for at least two weeks and include at least 5 of the following:

  • A predominant mood that is depressed, sad, blue, hopeless, low, or irritable, which may include periodic crying spells
  • Loss of interest or pleasure in usual activities
  • Poor appetite or significant weight loss or increased appetite or weight gain
  • Sleep problem of either too much (hypersomnia) or too little (hyposomnia) sleep
  • Feelings of fatigue or low energy
  • Psychomotor agitation or retardation—thoughts and movements are agitated and restless or abnormally slow and seemingly impaired
  • Feeling of worthlessness and/or guilt
  • Problems with concentration or memory
  • Thoughts of death, suicide, or wishing to be dead

People whose symptoms fit this definition may be diagnosed with a major depressive disorder.

See Diagnosing Depression in People with Chronic Pain

People whose symptoms do not completely fit this definition may still benefit from treatment. For example, some people who do not meet the criteria for a major depressive disorder have a condition called Adjustment Disorder with depressed mood. These people have milder depressive symptoms in response to a stress such as pain.

A doctor or other mental health care professional can evaluate a patient for depression and other disorders and make a recommendation.

People experiencing symptoms of depression can take the Depression Questionnaire.