Overview.
Classic symptoms of depression include:
- Persistent sadness
- A loss of interest or enjoyment in activities
- Sleeping more or less than usual
- Changes in appetite, fatigue, agitation
- Feeling worthless
- Excessive guilt
- Trouble concentrating.
Depression may also include irritability, social withdrawal, speaking or moving much more slowly than usual and thoughts of death or suicide. Other experiences that are commonly associated with depression can include drug and alcohol abuse, physical pain and chronic medical illness. However, symptoms of depression vary widely in severity and length. Some people may experience a few of these symptoms, and not find them particularly problematic. Other times, symptoms are severely disabling. Symptoms may appear and then go away on their own after a few days or weeks, while for others they persist for months or even years if left untreated. Whether someone is likely to benefit from treatment for depression depends on the severity of symptoms as well as how much they interfere with usual activities. See the assessment section, for more information.
Diagnosing Depression
At a certain level of severity and interference with daily life, depressive symptoms become a diagnosable health condition, as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), which is the most commonly used diagnostic manual for depression and other behavioral conditions in the United States. DSM-5 symptoms of Major Depressive Disorder are:
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To meet DSM-5 criteria for Major Depressive Disorder, a person must have experienced distress and/or interference with daily life and have had at least five of nine symptoms most days for two weeks or more. In addition, at least one of the symptoms must be persistent sadness or loss of interest or pleasure in activities, which are oftentimes referred to as the “cardinal” symptoms of depression. People may experience depressive symptoms that are due to alcohol, substance use, or other health conditions. For example, certain medications used in treatment of Hepatitis C can induce depressive symptoms and thyroid conditions may produce depressive symptoms. When depressive symptoms are due to a substance or better accounted for by another health condition, a depressive episode is not diagnosed because in those cases the symptoms are best treated by addressing the substance or other health issue.
Types of Depression
Bipolar Disorder is diagnosed when a person has had at least one depressive episode but has also had at least one period of very elevated or irritable mood that is out of character (i.e. periods of low and very high mood). Major Depressive Disorder is diagnosed when a person has experienced one or more depressive episodes without periods of elevated mood (i.e. just low mood periods). Major Depressive Disorder is much more common than Bipolar Disorder and is the most commonly diagnosed form of depression. If people do not meet all the criteria for a major depression, but are still bothered by their symptoms, they may be diagnosed with another condition such as Persistent Depressive Disorder (previously called Dysthymia) or Depressive Disorder, not otherwise specified. The symptoms and diagnostic requirements as described in DSM-5 have been identified through research on common symptom presentations of depression. The criteria allow for large variability in what depression actually looks like from person to person, which can sometimes make it difficult to identify. If you or someone you know is troubled by some of the depressive symptoms described, it is worth getting the symptoms assessed by a medical or mental health professional.
Patterns Over Time
What depression looks like over time can vary widely. For some people, depression is episodic, with symptoms present for distinct periods of time, and then improving after a few weeks or months to yield periods that are relatively free of depressive symptoms. Sometimes these improvements happen on their own without any treatment. Other people experience depression as more of a chronic condition where symptoms may increase and decrease somewhat over time, but depressive symptoms are almost always present. Either pattern may benefit from professional treatment. However, those experiencing chronic depression may be more likely to seek or require treatment because symptoms are less likely to improve on their own. Even so, those with an episodic pattern may feel better more quickly, or be less likely to experience another episode of depression if they receive treatment. Some people also experience a seasonal pattern to their depression, meaning that their depressive symptoms are worse during certain times of year. The most common seasonal pattern is a worsening of depression symptoms during the Winter months. For those with a seasonal pattern of depression, certain types of treatments, such as bright light therapy, are often particularly helpful.