Healthy friendships are based on mutual respect and generosity. Any friendship will go through periods when one person gives more than the other or when misunderstandings lead to hurt feelings. Good friends weather these times because of their shared desire to make each other’s lives better. But a friendship that is ­frequently out of balance can be destructive.

How do you know whether a friendship has crossed that line and is hurting you…and what should you do about it?

Recognize the Signs

A friendship may not be worth continuing if your friend…

Causes you more pain than pleasure. Examples: You get a knot in your stomach when you hear the person’s name…you rarely look forward to the time you will spend together…you increasingly dread speaking to him/her.

Often criticizes you. A basic expectation of friendship is that friends build each other up. Having a friend who is courageous enough to point out a blind spot in you can be valuable, but positive messages should dramatically outnumber negative ones.

Equally important is the way that negative feedback is delivered. Does your friend use a kindhearted tone and ask your permission first…or catch you off-guard and use harsh language?

Healthy feedback: “I’ve noticed something you are doing that might be hurting your chances of success. Is it OK if I point it out to you?”

Destructive feedback: “That was dumb.”

Ask yourself: Do I feel motivated to improve because of this person’s feedback? Or do I feel judged and resentful?

If your friend criticizes you to others behind your back, he/she is not acting as a true friend. The same is true if he makes remarks about others that he knows you will find hurtful. Example: He says something derogatory about someone who is overweight when he knows you are concerned about your own weight.

Takes without giving. Good friends don’t keep score—they take pleasure in enriching each other’s lives. But if one person is doing nearly all the giving, that’s a problem. If you always bring soup when your friend is sick…provide a ride to the airport…pick up the dinner check…but your friend doesn’t offer to help when you are sick or need a ride, the balance is unhealthy.

Your friend may not be as quick as you to anticipate a need, so don’t assume a lack of generosity just because he doesn’t offer. But if he always has an excuse when you ask for help—or if he says yes to ­requests but doesn’t follow through—your friendship is out of balance.

Manipulates. Manipulative people seek control by being indirect. Examples: Gossiping about mutual friends so that you wind up in the middle of their dispute…giving you uncomfortably lavish gifts and accusing you of being unappreciative.

Acts moody, irritable or sullen. We all have bad days and bad months. But someone who is consistently easy to upset and difficult to please—or who spends most of your time together complaining and venting—may be a source of stress you don’t need.

There is a saying that you are the average of the five people you spend the most time with. What this means is that spending time with positive, emotionally healthy people improves your own character. Spending time with negative people tends to pull you down to their emotional level.

Steps to Take

If you suspect that a friendship has become unhealthy, don’t just disappear from the person’s life. What to do…

Tell him how you feel, and give him an opportunity to change. Ask him why he does or says certain off-putting things, because when he does, you find yourself becoming defensive. This is a difficult conversation—confronting someone constructively is a challenge that many people prefer to avoid—but if you have not told the person what is bothering you, you bear some responsibility for the problem.

Try the “wince confrontation.” When you talk with your friend, be specific about what the troublesome behavior is, and keep your comments focused on behavior, not personality. Two techniques that can help you communicate clearly without putting the other person too much on the defensive…

The wince confrontation: Let the person know that confronting him is painful for you. (I call this the “wince confrontation” because you feel like wincing when you say it.)

Assertive humility: Present the problem as a request for help rather than a criticism.

You can combine these two communication techniques—for example, “I need your help with something (assertive humility). I’m wondering if we should take a break from each other, and I feel really sad saying this (wince confrontation). We’ve been friends for a long time, and the reason I’m at the end of my rope is that I have noticed a pattern where, when we are together, most of our time is spent with you talking about how terrible everything is. It’s wearing me down. I want to be able to look forward to our time together instead of dreading it. To do that, I need us to spend more time talking about what is going right in our lives rather than dwelling on what is wrong.”

If you do your best to communicate clearly and compassionately, you may feel shaken and sad, but you also will feel good about taking a stand on your own behalf.

Give your friend time. No matter how carefully you phrase your request, your friend may be upset or may resist the message. Don’t assume that this immediate response is his final response. Most people are not used to receiving straightforward feedback and may need time to process it.

If, after a few days or weeks, your friend still is not willing to change, don’t let things drift. State clearly that you need to take a break from—or possibly end—the relationship. Example: “I think it’s better if we take a break from seeing each other for a while” or “I think it’s best for us to part company.”

If the person still will be in your life—maybe you work together or go to the same school or house of worship—explain that, of course, you still will be civil but that the relationship will be no more than that.

If your friend changes his behavior but then reverts to his old ways, talk to him again. Example: “I’ve noticed that you’re doing (fill in the blank). Going forward, I would appreciate your not doing that because it probably will make it nearly impossible for us to have a relationship in the future.”

If your friend bad-mouths you to others, remind the person who told you about the bad-mouthing that he has a choice to not listen to the bad-mouthing.