Part 4 of a series

Depression and anxiety are like a pair of warring siblings. Both are disruptive and trying. They don’t want each other’s company, but are stuck together by virtue of the same parentage. Depression, after all, is often a product of rumination, the grating mental do-overs of ugly past events, usually with no solution in sight. Anxiety is the brainchild of too much forecasting of doom. Both seem to emerge from the sort of person who is stuck so securely in his mental time machine that he has no idea the roses are even there. Forget about stopping to smell them.

Psychologists tend to link the depressed and the anxious by personality. Both groups share the trait of “negative emotionality,” the propensity to harbor bad feelings such as anger and anxiety. (In contrast to those with depression, though, those with textbook anxiety spike their dourness with a dollop of wellbeing, energy, closeness to others, and the like.) And of course, the two temperaments feed each other. If your future is so terrible, what’s not to be depressed about? Conversely, if you rake over the past enough, you’ll undoubtedly unearth a goof that is sure to destroy your prospects. For all these reasons, not to mention shared genetic risk factors, lots of people who are depressed are also anxious—and vice versa.

Yet these practically conjoined twins of psychological distress have long been separated in psychiatrists’ diagnostic bible, the Diagnostic and Statistical Manual of Mental Disorders (DSM), currently in its fourth incarnation. A depressed person is someone who feels overwhelmingly sad and worthless, the DSM says, and who can no longer enjoy activities they used to like. They may also have thoughts of death or suicide. Generalized anxiety disorder (GAD)—to pick one of the many certified forms of fretting—involves excessive, and at least somewhat debilitating, anxiety and worry about more than one part of your life that you experience on most days for six months or more.

But what about all those ruminators who can’t help forecasting future doom—and yet don’t qualify as officially depressed or pathologically anxious? Currently, as of the DSM-IV, these folks remain in a kind of diagnostic limbo. Their pending label, “mixed anxiety-depressive disorder” is in the book’s appendix, a place for proposed ailments in need of further study. Accumulating data suggest that these people are numerous. In the United Kingdom, national surveys suggest that 8.8 percent of the population would qualify for mixed anxiety and depression as defined by the World Health Organization’s compendium of diseases—the International Statistical Classification of Diseases and Related Health Problems (ICD-10). By comparison, fewer people—only 7.7 percent—satisfied diagnostic criteria for major depression, GAD or a combination.

Many of the 8.8 percent are more than moderately miserable. Studies show that the impact of this cocktail of sadness and worry on quality of life is similar to that for anxiety disorders: 12 percent of sufferers, for example, have reported suicide attempts and the disorder accounted for 20 percent of all disability days in the United Kingdom. So these folks do seem to need help.

As a result of such findings, the framers of the DSM-5 originally proposed to move “mixed anxiety/depression” (with its slightly altered name) up to an official diagnosis, meaning insurance would reimburse you for treatment (which, drug-wise, is likely to be Prozac and its ilk). The proposed criteria for the new disorder included having three or four of the symptoms of major depression along with anxious distress. The latter required having two or more of the following issues: feeling nervous & anxious, inability to control worrying, having difficulty relaxing, being so restless it is hard to keep still, and fearing that something awful might happen. These problems must have plagued you for at least two weeks and must have caused “marked distress or significant impairment.” “Mood and anxiety disorders blur together,” says Scott Lilienfeld, a psychologist at Emory University. “This was an admission that they can’t be separated in any clean, neat way.”

And in this respect, the mixed disorder makes a great deal of sense. And yet as of last Thursday, the DSM-5’s framers seemed to take it all back. They reversed their initial push to promote this ailment to the body of the diagnostic bible. The criteria for mixed anxiety/depression were a bit vague and elastic, critics contended. The naysayers fretted that scads of mild chronic worriers—the Woody Allens of the world—would fall into it, their hypochondria ironically legitimized. The proliferation of false positives is a problem with the new DSM in general, some argue. “They are going to be diagnosing almost everybody,” Lilienfeld quips. Taking back the proposed mixed anxiety/depression diagnosis was one attempt to cut back on the number of newly mentally ill.

Of course, these critics could have been among the masses eligible for the proposed-now-nixed label, worriers that they are. But let’s give them some credit. Maybe they think they’re fine. And maybe they are.

Yesterday: Edward Shorter, a historian of psychiatry at the University of Toronto, argued that the principal diagnoses of the DSM—depression, schizophrenia and bipolar disorder—are artifacts and should essentially be discarded.

Tomorrow: Allen Frances, the chief framer of the DSM-IV, tells us why we lack biological tests for mental illness and how that deficiency hurts diagnosis.