East Carolina University's Department of Recreation and Leisure Studies said that in all cases, the changes in stress levels and mood were measured in comparison to a control group that experienced a Web-based activity similar in physical and mental nature to the game-playing groups.

The researchers measured heart-rate variability, electroencephalography and subjects' mood states pre- and post-activity.

"The results of this study are impressive and intriguing, given the extent of the effects of the games on subjects' stress levels and overall mood," study director Dr. Carmen Russoniello said in a statement. "I believe there is a wide range of therapeutic applications of casual games in mood-related disorders such as depression and in stress-related disorders including diabetes and cardiovascular disease."

Russoniello is scheduled to present the findings May 8 at the Games for Health Conference in Baltimore.

PopCap Games, which created the three puzzle and word games used in the study, underwrote the study and provided copies of the games for research purposes.