A no-no for the budget conscious: grocery shopping when hungry. Now scientists say shopping when sad can bust your budget, too.

The study, scheduled for publication in the June issue of the journal Psychological Science, explains one way a person's mood impacts consumer spending.

"It is important to increase understanding of how emotion and economic decisions interact," said lead researcher Cynthia Cryder, a doctoral student at Carnegie Mellon University in Pittsburgh, Pa. "The relatively new field of behavioral decision research is increasingly moving in that direction."

With funding from the National Science Foundation and the National Institutes of Health, Cryder and her colleagues conducted a study of 33 people aged 18 to 30. Participants who had watched a sad video clip offered more than three times as much for a water bottle than those who viewed a neutral clip from a documentary.

Results also showed that participants who were feeling blue and also had a high level of self-focus were the biggest spenders. Cryder's team determined self-focus levels by counting the number of times participants mentioned "I, me, my and myself" in essays they wrote about themselves.

Past studies have suggested down-and-out feelings trigger a person to become self-focused. So the sadder a person, the more self-focused they might become.

This combination, sad and high self-focus, likely causes individuals to devalue themselves and their current possessions, the researchers suggest. The result, they say, is an increased willingness to dole out more for material goods, presumably to enhance the sense of self.

The self-prescribed depression Rx might not be in vain. Past research has shown that spending money, whether for a selfish buy or a goodwill gift, can boost a person's self-esteem and mood, at least temporarily.

The sad-splurging effect could apply to other areas of a person's life, the researchers speculate, including stock investing and relationship shopping.