Depression, depressive mood disorder, anxiety

Depression: Seventeen million Americans each year are affected by depression.  Depression is classified as a mood disorder affecting people’s ability to function with everyday life due to feelings of anger, frustration, loss, or sadness.  Individuals may experience mild, moderate or severe depression and it may manifest as a single episode, recurring episodes, or chronic depression lasting more than two years.

The primary types of depression include:

• Major depression
• five or more symptoms must be present
• an episode must last at least 2 weeks, but tends to continue for 20 weeks
• Dysthymia
• a chronic, generally milder form of depression
• symptoms are similar to major depression but more mild in degree
• Atypical depression
• depression accompanied by unusual symptoms, such as hallucinations, delusions, and physical rigidity

Other common forms of depression include:

• Postpartum depression
•  experienced by 8% to 20% of women
•  occurs following the delivery
• Premenstrual dysphoric disorder (PDD)
•  experienced by 3% to 8% of women
•  depressive symptoms occur 1 week prior to menstruation and disappear following menstruation

• Seasonal affective disorder (SAD)
• experienced by 5% of adults
• the majority of those affected are women
• occurs during the fall-winter season and disappears during the spring-summer season

Depression may also occur with bipolar disorder.  Moods cycle between mania and depression in this disorder.

Signs and Symptoms

Most people feel depressed on occasion.  However, a person experiencing major depression feels substantially depressed for an extended period of time, experiences difficulty enjoying activities that were once pleasurable, and experiences at least five of the following symptoms for 2 weeks or more:

• Either agitation, restlessness, and irritability or inactivity and withdrawal
• Extreme difficulty concentrating
• Fatigue and loss of energy
• Feelings of hopelessness
• Feelings of worthlessness, self-hate, and inappropriate guilt
• Recurring thoughts of death or suicide
• Significant change in appetite (often resulting in either weight loss or weight gain)
• Sleep disturbances—at least 90% of people with depression have either insomnia (sleeplessness) or hypersomnia (excessive sleeping)
• Sudden bursts of anger and a lack of sex drive may also be associated with depression.

Causes

The causes of depression are thought to be multifaceted and involve a combination of biologic, genetic, and environmental factors.  Abnormal levels of certain brain chemicals exist in individuals experiencing depression.  Included are serotonin, acetylcholine, and catecholamines such as dopamine. Factors that may alter the levels of these brain chemicals and contribute to the development of depression are:

• Amount of exposure to light
• Certain medications, including those for high blood pressure, high cholesterol, or irregular heartbeat
• Chronic stress such as experienced from loss, abuse, or deprivation in early childhood
• Heredity  (Recently, the gene SERT has been identified and associated with depression.  It is responsible for regulating the brain chemical serotonin.)
• Nutritional deficiencies (especially folate [vitamin B9] and omega-3 fatty acids)
• Serious medical conditions, such as heart attack or cancer
• Sleep disturbances
• Social isolation