The newsletter of the Memory Disorders Project at Rutgers University

What is Depression

Depression is a disorder marked by altered mood, particularly sadness and apathy. Depression is one of the most common mental illnesses; some researchers estimate that 3-5% of the world's population experiences depression on any given day.

Everyone experiences feelings of sadness and depression from time to time.

Depression becomes clinically significant ("clinical depression" or "major depression") when it occurs over a period of days or weeks and includes several of the following:

  • Loss of self-worth or feelings of excessive guilt;
  • Loss of interest in usually pleasurable outlets such as hobbies, food, sex, entertainment, and friends, loss of energy, sleeping disorders (sleeping too much or too little), and recurrent suicidal thoughts or attempts. 

Depression Treatment

Clinical depression may be treated in several ways, including psychotherapy, antidepressent medication, and electroconvulsive therapy.

Clinical depression may result from imbalances in brain chemicals normally associated with signaling reward or pleasure, such as serotonin and dopamine. Depression may also result from several neurological disorders, including Alzheimer's disease and Parkinson's disease. Depression is also a common complaint among otherwise healthy elderly individuals.

Because a depressed individual will find it hard to concentrate, there may be memory problems, because the ability to learn and remember new information depends on the ability to pay attention to that information in the first place.

Further Reading:


by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain