Patient personality affects the accuracy of reports by friends and family members of mood history and symptoms and can cause missed diagnoses of depression, according to research published online by the journal International Psychogeriatrics.

Friends and family members of a person who is highly outgoing and fun-loving and who is likely to experience happiness and excitement, for example, often miss the signs that indicate the person is depressed.

"When a person who has enjoyed socializing and whose mood normally is positive becomes depressed, friends and family often don't recognize it. is inconsistent with the expectations that people have," said Paul R. Duberstein, Ph.D., professor of at the University of Rochester Medical Center and corresponding author of the journal article.

Missed diagnoses and "false negatives" can have grave consequences for patients with depression or mood disorders, the researchers stated.

Understanding and improving the ability of friends and family to identify depression could enhance the appropriate use of services for depressed older adults and improve the quality of treatment monitoring, the researchers concluded.

The research is based on the study of 191 patients aged 60 or older from the Rochester, N.Y., area and their friends and family members.

Older patients tend to discuss their health concerns with friends and family members, who often accompany them on visits to physicians. Information provided by friends and family members can help identify at-risk individuals.

When the research began, researchers hypothesized that friends and family would miss depression in a person who is introverted.

"But our research showed the opposite to be true," Duberstein said. "We found the signs of depression were more likely to be missed in people with an outgoing, extraverted personality."

The researchers also found that friends and family missed signs of depression in a person characterized as "agreeable," someone who is more trusting and more altruistic or who might be considered a conformist.

"It is important for people to understand that people who are highly extraverted and highly agreeable can become depressed and that the signs of depression for these people are more likely to be missed or detected by friends and family," Duberstein said "Don't assume that because someone is outgoing or agreeable that they are not vulnerable to becoming depressed."

Physicians should be particularly vigilant when interpreting reports from friends and family members of their extraverted or agreeable patients, the researchers stated.