Unipolar depression, also known as major depressive disorder, afflicts approximately 14.8 million American adults each year, according to the National Institute of Mental Health. Per the criteria of the American Psychiatric Association, its defining characteristics are depressed mood and loss of interest. Additional secondary symptoms must also occur, and may include weight and appetite changes, sleeping changes, feelings of worthlessness or guilt, and thoughts of suicide.
Defining Characteristics
For a diagnosis of unipolar depression, an individual must experience either depressed mood or loss of interest in most activities for at least two weeks. Depressed mood and feeling sad, unhappy or "blue" must occur most of the day, nearly every day, according to the American Psychiatric Association. Depression and sadness manifest in some individuals with uncontrollable crying.
However, not every individual with unipolar depression describes feeling sad. Some individuals instead simply express a total loss of interest in nearly every activity that they used to enjoy. This loss of interest will commonly result in withdrawal from normal activities and less social interaction, which may serve to perpetuate the depression.
Weight and Appetite Changes
Many individuals with depression notice a change in their appetite and sometimes as a result, their weight. Appetite changes can occur in either direction; some individuals notice a marked decrease in appetite and find that they have to force themselves to eat. Rapid and remarkable weight loss commonly occurs. However, others may notice an increase in appetite and resultant weight gain, according to the Mayo Clinic website.
Sleeping Changes
Individuals with unipolar depression also frequently report changes in their sleep patterns. These changes may manifest as hypersomnia, or sleeping significantly more than usual. They may experience difficulty getting up and may stay in bed all day if symptoms are severe. Other individuals report insomnia, or difficulty getting enough sleep. Insomnia may occur at any time during the night. Some people experience trouble falling asleep at the beginning of the night, others wake up during the night and have trouble falling back asleep, while others wake up unusually early in the morning and cannot fall asleep again.
Feelings of Worthlessness and Guilt
Bad feelings about oneself often dominate the thoughts of a person with unipolar depression. Low self-esteem is common, often manifesting as feelings of worthlessness, according to the American Psychiatric Association. The individual feels that she is not a good person or not capable of getting things done and that it is not worth trying.
The Mayo Clinic website reports that the individual with depression may also fixate on bad things that have happened in the past, such as personal failures, and feel unrealistically guilty for things he has done or has not done.
Suicidal Thoughts
If depression becomes severe, thoughts about death may begin to intrude. Some individuals may simply experience favorable thoughts about the idea of death, while others experience "suicidal ideation," which are favorable thoughts about the idea of suicide. Others progress even further and may make a specific plan or suicide attempt, according to the American Psychiatric Association.
Other Symptoms
Several other symptoms may also occur during a depressive episode, including trouble thinking or concentrating, chronic fatigue, indecisiveness and unexplained physical problems such as aches and pains, according to the Mayo Clinic website.
References
- National Institute of Mental Health: The Numbers Count: Mental Disorders in America
- "Diagnostic and Statistical Manual of Mental Disorders"; American Psychiatric Association; 2000
- Mayo Clinic: Depression Symptoms
