I have a problem. I have friends that I love to hate. My “frenemies”, as they are known. And they could be affecting my health.

Don’t get me wrong: I love these people. It’s just they drive me crazy. The worst was vain, delusional, and peppered every conversation with barely concealed insults. He would ask me about my news, only to start yawning exaggeratedly. “Boring!” he would then interject, in a fake Valley Girl accent (on the West Coast this may be acceptable, but this was in London).

It sounds trite, but this would leave me seething for days. Yet when, after years of frustration, I’d plucked up the courage to cool things, I was left with a perverse feeling of guilt and remorse, over all the good that is beginning to slip away too. When I wasn’t the butt of his jokes, he could be pretty funny.

I’ve discovered these friendships are beginning to attract serious attention from psychologists. They even have a technical term for it – “ambivalent relationships”. According to Julianne Holt-Lunstad at Brigham Young University in Utah, on average about half of our social network consists of people we both love and hate. “It is rare to encounter someone who doesn’t have at least one ambivalent relationship,” she says.

And that might be a more serious concern than it first appears. Holt-Lunstad’s work suggests that “frenemies” could be far more damaging than the people you actively, unambiguously hate; they might even damage your well-being and put your health at risk. So why do we continue to maintain these toxic friendships?

Support network

To understand this we need to look at the impact our social networks can have. For the most part, a lively mix of friends and acquaintances was thought to be protective. Analysing 150 published studies, Holt-Lunstad found that strong social ties reduce your risk of death to about the same extent as quitting smoking. Being lonely was about twice as harmful as being obese.

How come? Friends are meant to help us to relax and protect us from stress. Stress raises blood pressure, and ramps up the release of inflammatory molecules that could increase the risk of a whole host of ailments – whereas friends can help to soothe some of these responses. Conversely, the unhappiness of loneliness can itself amplify many of these processes and lead to other complications, like sleep-loss.