If you have so-called unipolar depression, could you possibly be bipolar waiting to happen? Perhaps you haven’t been having luck with your antidepressant. Let’s investigate.

In 2002, the NIMH began recruiting 4,000 patients with unipolar depression for the largest series of antidepressant medication trials ever conducted. The study is known as STAR*D (Sequenced Treatment Alternatives to Relieve Depression). In the first round of STAR*D, all the patients were tried on flexible doses of the...