Clingy behaviors often come from a feeling of inadequacy or lack of self-esteem, according to psychiatrist Mark Banschick in his Psychology Today article "Overcoming Neediness." A clingy friend may feel that he is nothing without you or that he needs you to make him a complete person. If he's always putting himself down while putting you up on a pedestal, he may have low self-esteem. If he calls nightly asking you to come over and watch TV, he may find it hard to relax and enjoy times when he's alone.

Stalking includes repeated harassment that doesn't let up, according to Brown University's Health Education website. While a clingy friend may not "stalk" you to the extent that you need to call the police, any harassing behaviors can get annoying and make your life uncomfortable. For example, your friend calls you every hour, sends text after text and shows up at your job -- uninvited -- on your lunch hour five days a week. Take a look at her behaviors in the context of your relationship. If you have always had a communication pattern in which the two of you talked all day every day, and then suddenly you stopped because of a new job or a new relationship, her behavior isn't really clingy. On the other hand, if you've never had this type of constant-communication type of friendship, and she won't stop calling, she is acting needy.

Trying to impose guilt to get you to hang out is a signal that your friend has gone from a confidant to a clinger. Asking you to hang out on a Saturday night is normal social behavior. Making you feel you've done something wrong for having other plans isn't -- it's a sign of neediness. For example, your friend calls you on Friday afternoon and asks you to go to the club with him. You explain that you have a date. Instead of saying "OK, have a good time," he whines, "You can't leave me alone. I have to hang out with you tonight. I've been waiting all week to go to the club with you."

When normal friendship behaviors -- such as wanting to spend Saturday nights together -- gradually intensify, it can be difficult to recognize that your friend has become clingy. If she used to be satisfied with your one-night-a-week hangout but now wants to spend four or five nights a week with you, she may be feeling more dependent due to temporary circumstances. If she is experiencing instability in other areas of her life -- due to a move, change in jobs, change in family structure or another major transition -- she may consider your time together one of the few ways to feel stable. If you notice your once-unflappable friend growing anxious when plans have to be canceled, try to make some extra time for her and catch up on any big changes in her life.