BOSTON — Women may have longer depressions than men partly because they tend to dwell more on the low mood, a researcher suggested this week.

That may be a way to figure out why the depression occurred, but works “in a way that gets you stuck in a downward cycle,” said Susan Nolen-Hoeksema.

Some small preliminary studies lend support to the hypothesis, the Stanford University researcher said at the annual meeting of the American Psychological Association.

She called it one of several possible explanations for recent, early evidence that women tend to have longer depressions and run a higher risk of multiple episodes.

The rumination reaction includes focusing on such things as how tired and unmotivated one feels, and on possible causes and consequences of the depression.

It contrasts with a “distractive” response, in which a person does things to get his or her mind off the depression.

In one study, 43 men and 36 women, all depressed, filled out a form every day for a month. They reported how they felt that day, how severe the depression was, and which of 32 coping responses they used that day.

On average, women reported more ruminative responses, such as seeking solitude to think about their depression, than men did. Their average was about three out of the 16 listed, vs. two for the men, Nolen-Hoeksema said.

The difference was statistically significant, she said. No one person could report all 16 ruminative responses because some of them were mutually exclusive, she said.

Analysis also showed that the degree of rumination was related to the depression’s impact on a person, she said. Impact accounted for severity and duration of depression.

Degree of rumination also was related to the number of days that a person felt moderate or severe depression, she said. Gender played no role in that, she said.