Mika / zefa / Corbis

There's a lot to feel down about this month: the subprime mortgage crisis, stormy, unpredictable weather, rising gas prices, presidential primary free-for-alls. So, it would be easy to believe the theory set forth by Dr. Cliff Arnall, a researcher from Cardiff University, that the third Monday of the month (Jan. 21, this year)  a day he calls Blue Monday  will be our most depressing day of the year. Arnall bases his yearly prediction on a formula he developed, which factors in the weather, consumer debt from holiday spending and failed New Year's resolutions and arrives at that conclusion that we'll hit rock bottom on Monday the 21st. Aside from the fact that Arnall's theory has been discounted by many in the academic community, I've got a better way of finding the true nadir of depression: Look to our search behavior.

In the digital age we're likely to turn to search engines just as often as we would confide in friends and medical professionals to gauge our psychological state. If we think we're suffering from a real bout of the blues or a mental crisis, we're likely to Google the symptoms or find a chat group in the hopes of performing a self-diagnosis. In fact, online searches for "depression" are among the most popular searches sending traffic to the 5,900 sites that we track in the Hitwise Health and Medical category  but the peak is not in January. According to our Internet behavior, our depression spikes reliably in mid-November every year, right in time for Thanksgiving, the launch of the holiday season.

To confirm this timing I took a look from a different perspective. If we're depressed, we're probably also seeking pharmacological help. By aggregating the traffic to the websites of the top antidepressants and charting visits to those sites over the last three years, a very interesting pattern emerges. The spike in traffic to the official websites for drugs like Lexapro, Prozac, Paxil and Cymbalta occurs in late October and early November, two weeks ahead of the height in searches on "depression." It's almost as if people anticipate their holiday depression and start shopping early for their drug of choice.

Another surprise lies in the demographics of visitors to antidepressant websites  they're not who you would expect. If visitors to Lexapro.com, for example, are at all representative of the typical depressed individual, depression during November is an affliction primarily of the young and the old, but not of the middle-aged. The two age groups that account for the largest portion of site visitors are 18 to 24 (26.2%) and over 55 (27.6%). Visitors to Lexapro's site also tend to have average to above-average incomes: 51% of visitors come from households earning between $60,000 and $150,000 per year, while 20% come from households that earn over $150,000  a sample, perhaps, not of the depressed in general, but of those who can afford to seek treatment.

So, Dr. Arnall, despite the failing economy, the storm of the century here in Northern California, a disappointing roster of presidential candidates and deciding that New Year's resolutions aren't for me this year, I'm feeling pretty good about things. If search data is any indication, I'm not alone.