Like parasites, Shadows live vicariously; they draw sustenance from your enthusiasm, your ideas, your creativity. They accomplish this by delving into your private life with countless questions. I was flattered at first when a new acquaintance showed great interest in my writing, emulated my style of dress and copied my hairstyle. But when she started befriending my friends, alarm bells rang in my head. Before long, her presence felt as stifling as someone's hot breath in a crowded elevator. I had to shake her off.

Diggers are the most devastating type of energy vampire. Their bite sinks deeper than that of Talkers, Poor Me's and Shadows, and the symptoms are harder to treat. Diggers work at the soul level. They siphon your energy by filling you up with their private darkness. Like Shadows, they will bait you with questions and charm you by paying rapt attention to your revelations. Then they push deeply into you and, once inside, they tap into your insecurities to sow doubt and dissatisfaction.

This is the "friend" who asks you about your new job or lover. Her empathy encourages you to reveal your concerns, but once she has found the weak spot in your story, she will work that until it overwhelms everything else. Mysteriously, you come away from the conversation feeling less: less happy, less certain, less loved. And the Digger has absorbed all that you have surrendered.

Like Count Dracula in Bram Stoker's tale, the energy vampire cannot be satiated by anyone. And so the task of feeding themselves, which leaves others depleted and diminished, becomes a never-ending labor. Need in itself, of course, is not a bad thing. Reciprocal exchange of energy and love is what friendships and partnerships are built on.

But energy vampires never reciprocate. Contact with them is more like a psychic assault than an exchange. Because they have no awareness of what they are doing, they feel no guilt or remorse. It is up to the victim to stop the psychic Dracula.

If you find yourself surrounded by energy vampires, beware -- you may need them as much as they need you. If you always put friends' desires before your own, rescue acquaintances from drowning in their melancholia or fall strangely ill after the departure of demanding houseguests, you may be an unconscious target of an energy vampire. Like the sleepwalking victims of Stoker's Count Dracula, you need to wake up.

You cannot defeat energy vampires with rosaries or necklaces made of garlic. But you can follow the basic lesson taught in self-defense courses: Cultivate awareness. Recognize their presence when they appear in your circle. And then avoid them. Because energy vampires are real. They may not wear black capes and bare their fangs on Halloween. But they are truly scary -- every season of the year.