I was much further out than you thought
And not waving but drowning.
Who could object to a "mood-stabilizer?" It sounds as gentle and as appealing as a spring rain. Indeed, when I mention it to patients they often seem to like the sound of it (if not quite so much as "nerve pill," which is really hard to turn down). "Antidepressant," by contrast, has sort of a grim ring to it, perhaps because "anti-" sounds, well, oppositional, and "-depressant" like, well, a downer. Names matter.
Ah, that vexed bipolar subject again. When DSM-V finally emerges (or to paraphrase David Hume, falls stillborn from the printing press) in the next few years, probably the single greatest impact upon everyday clinical practice will involve the evolving classification of bipolar disorder (the classification of Axis II/personality disorders may run a close second).
In the current American Journal of Psychiatry Christopher D. Schneck, M.D. joins the growing chorus supporting a broader bipolar definition, one that includes so-called "mixed depression," or depression associated with "subsyndromal" manic symptoms (which may include mood lability, irritability, agitation, or "racing thoughts" that fall short of a manic episode). In the current classification the only possible "mixed episode" is the simultaneous occurrence of a full major depressive episode and a full-blown manic episode for one week (these states can be clinically impressive and personally appalling, but are uncommon).
What is driving this reconsideration is the disappointingly poor performance of antidepressants not only in general, but particularly in bipolar depression. Run-of-the-mill antidepressants haven't had a good few years, frankly. First came concerns about medication-induced suicidality, then scandals involving research publication bias, and now this, the possibility that wide swaths of the clinical territory previously thought suited for antidepressants will at some point shift to bipolar states calling for mood-stabilizers. Is anyone "just" depressed any more? And I won't even get into the potential overlap with borderline personality and other characterologic and cultural issues.
A diagnostic shift may well be called for, but the potential problem is bipolarity as "the night in which all cows are black," that is, the bipolar concept is so elastic as to include a large segment of the psychiatric population. For instance, it is very rare for me to see a depressed or anxious patient who does not, when specifically asked, endorse "mood swings." Depression and anxiety in themselves make people more sensitive to everyday stressors, which can generate mood instability. Similarly, insomnia is nearly ubiquitous in depressed and anxious states. When people lie awake at night they tend to focus on their (inevitably fretful) thoughts more, which--again, when specifically asked--is highly likely to be confirmed as "racing thoughts."
Another problem is the treatment implications of sending a patient down the bipolar diagnostic road. Clinical inertia being what it is, there is often no turning back, at least for a long time. Antidepressants, while not without their problems, tend on average now to be relatively cheap, well-tolerated, and straightforward to take. Mood-stabilizers, by contrast, are often very expensive, can cause weight gain and other troubling side effects, and may require periodic blood tests for monitoring. Easier-to-take mood-stabilizers have been sought in Neurontin and Topamax, but these haven't turned out to be effective for this indication. Many clinicians now--granted, somewhat lazily--reach for atypical antipsychotics for bipolar disorder, but those are fraught with risk and expense as well.
I don't recommend a reactionary, strictly by-the-DSM-IV, approach to bipolar disorder, and I've treated plenty of ambiguous cases with mood-stabilizers, but it is never a straightforward process. Often folks in this gray area end up taking several antidepressants and mood-stabilizers from different doctors over multiple years, and one has to try to figure out what seemed to work best; the name for what is going on is often quite conjectural. In this business we ultimately have only one tool in the box: pragmatism.