For the almost 15 million adults living with depression, it can be a daily struggle to stay in touch with reality. Here Jon G. Allen, PhD, senior staff psychologist at the Menninger clinic in Houston and author of Coping With Depression, explains the basics of this disorder.

What is depression?
Depression is more than just feeling sad; it’s a serious psychiatric disorder that impairs your ability to function.

What are the main symptoms?
Weight loss or gain, a diminished interest in pleasure, insomnia, loss of energy, feelings of worthlessness or guilt, and thoughts of suicide.

What causes it?
Genetics, biochemical changes and certain stressful life events that cause psychological problems. These problems may affect someone’s brain function and also influence mood.

Are certain groups at higher risk?
Depression knows no cultural boundaries, but women are twice as likely to suffer from depression as men.

How is it diagnosed?
By simply visiting a doctor and getting an evaluation.