Certain friendships can effect your health based on a study that was published in the Annals of Behavioral Medicine. Friendships with too much drama can significantly raise your blood pressure.
The study was conducted by psychologists who measured the blood pressure of 107 people as they talked to their friends. The friends were either identified as supportive or difficult. When rehashing bad news or memories, the subjects' blood pressure soared twice as high with frenemies compared to the average of 10 points when speaking with friends. The subjects' blood pressure stayed high throughout a 12-minute break, suggesting that just being near difficult "friends" was stressful, says the lead study author.
Source: Women's Health Magazine