In myth, vampires drink the blood of others in order to keep themselves "alive," if only marginally. The story of the "living dead" is essentially one of desperate and thirsty people draining the life blood out of others.

While real vampires don't exist, I have learned that emotional vampires are everywhere. Again and again, I find myself treating patients whose energy and autonomy and optimism are being siphoned off by others.

Emotional vampires (like the mythological ones) drain the life force from their victims without giving it a whole lot of thought. Their anemic sense of self automatically leads them to define themselves by the excessive and toxic control they exercise over their children or their spouses or their friends.

These are the psychologically living dead who, for example, suggest to their children that the world is an unpredictable, unforgiving place and then cast themselves as the only force able to keep their children safe. They create weakness in their sons and daughters in order to have a lifelong role as critical supports in their childrens' lives.

These are the psychologically living dead who look for every opportunity to criticize their spouses and erode their self-esteem (or fuel their addictions), in order to be the ones their spouses forever turn to for support.

These are the psychologically living dead who, as supervisors at work, never let those working with them feel competent or confident, always ensuring their roles as saviors of the company. Emotional vampires feel "fuller" when they make others doubt their self-worth, their ideas and even whether they are loveable. (By the way, governments can do this to their citizens, as well.)

Just like the myth suggests, the pathologies of emotional vampires are contagious. Sadly, once someone has been "bitten" by an emotional vampire, he or she is much more likely to become one.

The best defense against emotional vampires is to think about whether one might have his or her teeth buried deep in your soul right now. Is anyone close to you making you think of yourself as weak, then promising to keep you safe? Is anyone close to you telling you that you're lucky he puts up with you, because no one else would?

If you are feeling disempowered, start listening very carefully for toxic messages from someone close to you.

It's a wonderful thing about human beings_ Once they see the truth, it frees them.

Dr. Keith Ablow is a psychiatry correspondent for Fox News Channel and a New York Times bestselling author. His book, "Living the Truth: Transform Your Life Through the Power of Insight and Honesty" has launched a new self-help movement including www.livingthetruth.com. Dr. Ablow can be reached at info@keithablow.com.

Dr. Keith Ablow is a psychiatrist and member of the Fox News Medical A-Team.