When depression rears its head, take notice, even if the symptoms don't add up to major depression.

That message comes from Joshua Fogel, PhD, and colleagues. They found that people with minor depression were six times more likely to develop major depression over 15 years.

They suggest that doctors ask patients a simple question — "Have you felt depressed or sad much of the time in the past year?" — to get an inkling of the patient's frame of mind.

You could ask yourself the same question. If the answer is yes, or if you suspect depression for other reasons, get help. Depression is common but a variety of treatments are available.

The study was presented in Washington, at the American Psychological Association's annual convention.

Your Guide to Depression

What Is Minor Depression?

Minor depression has some but not all of the traits of major depression. Diagnosis requires at least two but less than five out of nine depression symptoms. One of those symptoms must be sadness or lack of interest in activities, write the researchers.

Major depression symptoms include:

· Feeling sad, depressed, or tearful (or, for kids and teens, irritable)

· Marked drop in interest or pleasure in activities

· Significant changes in weight or appetite

· Sleeping too much or too little nearly every day

· Feeling restless or sluggish

· Feeling worthless or excessively guilty

· Having trouble concentrating

· Fatigue or loss of energy nearly every day

· Suicidal thinking, suicide attempts, or thinking a lot about death (not just fear of dying)

Those symptoms are listed in the DSM-IV, a manual used for psychiatric diagnoses.

There has been some discussion about whether minor depression is a separate disease, but most experts consider it part of a spectrum leading to major depression, write the researchers.

"Although called 'minor' depression, its impact is not minor," write Fogel and colleagues. They note that minor depression is more common than major depression.

Drowsy Days May Signal Depression

Long Look at Depression

Data came from a study of more than 1,600 adults living in Baltimore, Md. Participants were interviewed twice, 15 years apart.

In the first interview, 101 people had minor depression. Fifteen years later, about 19 percent of them had developed major depression.

Participants with minor depression were six times as likely to develop major depression during the study, notes Fogel. He works in the economics department of Brooklyn College of the City University of New York.

Exercise for Depression Rivals Drugs, Therapy

Red Flags, Gender, and Age

Suicidal thinking, appetite/weight issues, and sleep difficulties were the three symptoms most strongly linked to the slide from minor to major depression.

More women than men had minor depression. Women were also twice as likely as men to develop major depression.

Minor depression was more common among younger people (aged 18-44 years) than among older participants, the study shows.

Quiz: Could You Be Depressed?

Health Link?

A lot can happen in 15 years. Did other illnesses trigger participants' depression?

People who had strokes were more likely to develop major depression. Cancer, diabetes, heart problems, high blood pressure, asthma, and arthritis or rheumatism weren't linked to major depression, contrary to other studies, the researchers note.

"Screening for depression should be considered part of the examination in any doctors' office. This may help address those individuals who suffer from minor depression and provide them with help to allow them to receive the appropriate treatment early on. This may help prevent an occurrence of a more severe and debilitating episode of major depressive disorder." writes Fogel, in a news release.

Depressed heart attack survivors have been found to have a greater risk of dying or having more heart problems two years later.

Recently, Danish researchers showed that tired, depressed people were not more likely to develop cancer. However, depression's health effects are still being studied.

Visit WebMD's Emotional Wellness Center

By Miranda Hitti, Reviewed by Brunilda Nazario, MD

SOURCES: American Psychological Association Convention 2005, Washington, Aug. 18-21, 2005. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, "Criteria for Major Depressive Episode." WebMD Medical News: "Depression Dangerous After Heart Attack." WebMD Medical News: "Depression, Fatigue May Not Raise Cancer Risk." News release, American Psychological Association.