I continue to read research that reveals what most of us know: Having friends is one of the key factors in extending longevity, maintaining good health, managing stress and making life worth living. Most of us are also keenly aware that some friendships can be draining. New research confirms this too: unhealthy friendships can be harmful to your health.

I've a client (I'll call her Lisa) who recently told me that as she gets healthier and examines her friendships she's keenly aware that her relationship with a close friend feels lopsided. After this long time acquaintance had a devastating loss some years back, a closer friendship unfolded as Lisa offered her support and gave her friend "space" to recover and grieve in her own way. Five years later Lisa continues to "be there" for her friend, give her benefit of the doubt and extend herself despite feeling lousy after every time they get together. Lisa said, "My friend has made a huge effort to recover from her loss, but she also continues to believe that the strategies that have worked for her are the ones I need to use to resolve my own problems. Moreover, every time I'm with her I realize I'm constantly interrupted with her opinion which, with few exceptions, feels judgmental. Sometimes I can't get a word in edgewise as she chatters away telling me how great her life is. Every opinion or story I offer is followed by a put-down."

Lisa's friend, as described, is what I call "a zapper." When Lisa attempted to talk to her friend about her experience she got zapped again with the comment, "You're too sensitive."

In her book WHEN FRIENDSHIP HURTS, Jan Yager, a sociologist at the University of Connecticut says that friends who give us sly insults and competitive one-upmanship "can be as devastating to our health as poor self-esteem or extreme stress." Yager describes 21 types of potentially negative friends who should lead us to consider whether we should attempt to detoxify the relationship or simply cut bait.

As I've "matured" I've close friendships which have grown deeper and others which I've chosen to temper, wind down and/or abandon. My own criteria has to do with how I feel after I'm with that person no matter how eager I am to see them again before we meet. I realize it's often got as much to do with me as it does to do with them so every friendship I have ultimately gives me an opportunity to learn more about myself. In some cases I simply forge good boundaries. For example, I've a long time friend who simply cannot keep a confidence. Because I enjoy her company I've learned to be discreet about the information I share with her. In other cases I've subjected a friendship to a cooling off period. I learned that strategy the hard way when I once engaged in a lengthy email discussion after a friend and her husband broke a promise he made to me. Knowing the friendship was important each of us attempted to make the other understand what we were feeling. The exchange disintegrated until it ended permanently. I look back and wish I'd never pressed the email "send" button.

Friendships are something we can choose to invest in or ignore. When we know friends care about us, support us, leave us smiling and put effort into catching us when we start to fall or dusting us off if we can think of it as a deposit into a bank account that builds as we continue to have rewarding interactions. When we disagree about something some of that investment might be withdrawn but it can quickly be restored as we put our best foot forward to maintain something important to both of us. However, when the bank account is depleted through a series of small altercations or, all at once, when trust is betrayed, it becomes important to decide if we want to have a discussion or simply pull the plug on the friendship.

If you are especially "nice" opening a relationship for discussion may seem daunting. Nevertheless, if you can't confront someone when they are treating you badly, attempt to remember that allowing yourself to be mistreated hurts you and your health. Open lines of communication. Maybe your friend doesn't know you consider his/her behavior harmful. Only you can decide if it's worth the effort.