Atypical Depression

Atypical depression -- a type of depression that can be difficult to treat - has symptoms that include weight gain, sleeping too much, and feeling anxious. Here is information about the causes of atypical depression and its diagnosis that you can use to help you talk with your doctor about it.

What is atypical depression?

Atypical depression is a subtype of depression with certain specific characteristics. A person with classic clinical depression has at least five, and possibly more, of the following symptoms or signs:

• sadness
• loss of energy
• feelings of hopelessness or worthlessness
• loss of enjoyment in things that were once pleasurable
• difficulty concentrating
• uncontrollable crying
• difficulty making decisions
• irritability
• increased need for sleep
• insomnia or excessive sleep
• unexplained aches and pains
• stomachache and digestive problems
• decreased sex drive
• sexual problems
• headache
• a change in appetite that causes weight loss or gain
• thoughts of death or suicide
• attempting suicide

In general, people with atypical depression don't have as many of the symptoms that people with classical depression may have. They also tend to have first experienced depression at an early age, during their teenage years.

Despite its name, atypical depression is probably rather common. Some doctors believe that it is underdiagnosed. Researchers are considering whether or not atypical depression might be a type of dysthymia -- a low-level depression that has lingered for at least two years. Researchers are also investigating the idea that atypical depression may be a milder form of bipolar disorder called cyclothymia. People with cyclothymia typically have less extreme switches in mood.

What are the symptoms of atypical depression?

The main characteristic of atypical depression that distinguishes it from major depression is mood reactivity. In other words, the person with atypical depression will see his or her mood improve if something positive happens. In major, or melancholic, depression, positive changes will not bring on a change in mood. In addition, diagnostic criteria call for at least two of the following symptoms to accompany the mood reactivity:

• sleeping too much (hypersomnia)
• eating too much (hyperphagia), resulting in weight gain
• having a more intense reaction or increased sensitivity to rejection, resulting in problems with social and work relationships
• having a feeling of being weighed down, paralyzed, or "leaden"

A doctor will investigate physical causes for any of these symptoms. That includes doing blood tests for thyroid problems or hormone levels. Atypical depression can co-exist with other diseases. For example, it might occur with hypothyroidism -- low levels of thyroid hormone -- which has symptoms that include depression and weight gain. Studies have also shown that atypical depression has been found in some people with adult-onset human growth hormone deficiency.

What causes atypical depression?

Depression is believed to be the result of a chemical imbalance in the brain. These chemicals -- neurotransmitters that facilitate communication between brain cells -- include dopamine, serotonin, and norepinephrine. While the exact cause of depression is unknown, there are risk factors for depression, including:

• a family history of depression
• a significant loss -- from death, divorce, or separation -- that results in grief
• interpersonal conflicts and related emotions such as guilt
• any type of abuse -- physical, sexual, or emotional
• any type of major life event such as moving, changing or losing a job, graduating, retiring
• any type of serious illness such as cancer, heart disease, stroke, or HIV
• drug or alcohol abuse
• isolation or exclusion from family, friends, or other social groups