When you think about depression, you probably think of the debilitating, keep-the-shades-closed-and-stay-in-bed-all day kind of intense sadness that sends people to the edge of suicide, if not past it. But depression is actually much more common, and much more varied, than most of us realize. Many people suffer from what I call "high-functioning" depression, which is similar to high-functioning alcoholism. These people might look perfectly fine on the outside, but there are serious problems within. I am one of them.

I'm letting you in on my big secret because I think my experience reflects that of a great many Christian women. If you met me, you'd never guess I'm depressed. I smile. I laugh. I get out of bed every morning to care for my children. My house is reasonably clean. Even my husband has had a hard time believing I'm depressed because I don't fit the typical image of a depressed person.

There are lots of moms just like me who go through their days with the veneer of having their act together while inside they know they are barely managing to get through till bedtime. Sadly, many of these women don't realize that the numbness they feel might be indicative of a real illness that will only get worse if left untreated. In their excellent book Unveiling Depression in Women, Dr. Archibald Hart, Dean Emeritus of the Graduate School of Psychology at Fuller Theological Seminary, and his daughter, Christian psychotherapist Catherine Hart Weber, note that women tend to experience atypical symptoms, such as oversleeping, increased appetite and resultant weight gain, anxiety, guilt over not getting things accomplished, sensitivity to rejection, and self-consciousness. When I first read this description, I was struck by the idea that much of what mothers experience each day -- exhaustion, anxiety, guilt, a sense of failure, the feeling of not really connecting with people -- can be aspects of depression.

Even if you're not experiencing some form of depression, the odds are very good that a woman you know is. Recent studies have suggested that some 21 percent of women in America have experienced at least one major depressive episode in their lives. That means it's likely that one of every five women you know has been or will become depressed. Rather than be surprised when a mother becomes depressed, we should be shocked that there aren't more of us openly talking about what is a remarkably common experience.

Depression in mothers often grows out of the clash between their hopes for themselves as mothers and the reality of what mothering is really like. Think back to when you were a child. When you imagined your life as an adult, it probably didn't include driving the minivan to swim practice at 5:00 in the morning or being bone tired from a day of keeping up with two kids under four. You likely never imagined there would be days when you didn't like your children or would lack the patience to answer their never-ending questions.

When we picture ourselves as mothers, we picture ourselves at our best, as the women we want to be, the mothers we believe we can be. When that dream is dashed and we come face-to-face with our own failings, we find it difficult to adapt to this diminished version of our selves. We face the loss not just of a dream but of a chunk of our self-esteem that tells us we will rise to the incredibly important task of raising children.

When a woman feels as if she's failing her children because she's not the patient, creative, all-loving mother she wanted to be, the sense of loss will grow deeper. When she doesn't like her children, when she thinks about running away, that sense of loss will grow deeper still. And when she's told that these feelings are sign of personal and spiritual weakness, the depth of this loss can cause a woman to spiral into a serious depression.