"Before the procedure, people filled out a questionnaire where they rated various adjectives describing how they felt, including: distressed, upset, guilty, scared, hostile, irritable, ashamed, nervous, jittery and afraid.
The study authors found that people who were more likely to have a greater degree of these negative feelings had a greater occurrence of adverse events from the procedure, like slow heart rate or abnormal blood pressure."
For the full article, click here: http://time.com/4131926/your-mood-can-predict-how-well-your-surgery-goes-study/