New research have helps confirm that women with jobs that demand long hours may be more prone to depression. Researchers found that compared with women who worked a standard 40-hour week, those who were on the clock 55 hours or more typically reported more depression symptoms.

The same was true of women and men who usually worked weekends as well as weekdays. The findings, based on thousands of British adults, do not prove that long work hours were the culprit. "Workers are complicated creatures," said lead researcher Gillian Weston, of University College London. "And it's not possible to [account for] every potential influence when looking for associations in an observational study."

Still, she said, her team was able to factor out a number of factors that affect depression risk -- such as income and education, and whether people were married or had children. And still, long work weeks remained linked to a higher risk of depression symptoms.

The findings have implications in a world where people are increasingly expected to work outside the traditional 9-to-5 window, according to Weston's team. Theresa Nguyen is a licensed clinical social worker and vice president of policy and programs for the nonprofit Mental Health America. She said that in recent years technology has sharply reduced workers' "safe spaces" of personal time.

"Our smartphones have created an expectation that you'll always be available. You'll answer emails even when you're on vacation," said Nguyen, who was not involved in the study.

For women -- who have always borne the stress of balancing work and family life -- the added time demands can be especially daunting. "There's the pressure that society puts on us, and that we put on ourselves," Nguyen said. "As women, we worry about being at work and away from family."

In most countries, Weston said, women typically work less than men do, and those who are married with children often cut down their work hours.