The most common complaints I see as a primary care physician are headaches and head colds. Generally, both of these disorders are easily diagnosed and treated, which means that people willingly come to the doctor's office when they have one or the other of them.  

Another common - but much more dangerous - complaint that comes through my door is depression, and many of my patients are neither familiar with this disorder nor quite ready to be treated for it.

Because the classic symptoms of depression are known to most - sadness and frequent crying, a sense of worthlessness, and a pessimistic outlook - many women know when they're depressed and can say, "It's happening again."

But many other symptoms and signs of depression are not so straightforward and easily noticed, and many women are unfortunately suffering from depression without knowing it. Here are some of the less well known symptoms of depression.

• Loss of interest or pleasure in activities previously enjoyed, including sex.
• Fatigue, as well as difficulty concentrating and remembering.
• A change in sleep patterns: Either an inability to fall asleep, an inability to get back to sleep after waking in the night, or an excessive need for sleep, as when a person craves a nap despite getting 10+ hours of sleep a night.
• A change in appetite, with either weight loss or weight gain. Some of us who are depressed cope by eating more, while others can't be bothered to eat.
• Thoughts of death. Considering life to be useless or meaningless is not a normal thought, nor are thoughts of suicide.
• Physical symptoms with neither a medical explanation nor a normal response to the usual treatments. These are referred to as somatic symptoms in medical lingo, and they often include headaches, muscle aches, or belly pain. In fact, the makers of one depression medication have even targeted this group of sufferers with the catch phrase, "Depression hurts."

Why write about depression here, in a women's health blog? Because women are twice as likely as men to suffer from depression. And 10 percent of all men and women in the U.S. will suffer a depressive episode in their lifetime. That's a lot of women.

Even though more women are affected by depression at some point than by breast cancer, my sense is that we have put much greater emphasis on examining our breasts than on evaluating our own moods. And yet the implications of untreated depression can be just as horrendous as those for cancer.