Between Diagnoses

I have a close friend who’s frustrated with her psychologists and psychiatrists. She’s been diagnosed with borderline personality disorder, bipolar disorder, major depressive disorder, and ADHD. Those are four separate diagnoses, and three of them came with three different prescriptions. However, if one goes through the necessary symptoms and their durations in the DSM-IV or V, it becomes clear that due to a few technicalities, my friend qualifies for neither of the four disorders she apparently has.

The DSM makes diagnosis so simple, so why can it be so inconsistent? Of course, the DSM’s diagnostic criteria are not tests, per se. And yet they can be easily rewritten into test format. Depression’s A criterion is if five or more of nine certain symptoms have been present during a 2-week period. So this can be made into a simple questionnaire: “in the past two weeks, have you x, y, z, etc.?” The results are then tabulated, and if the score is above 5, the A criterion is met. The further questions for the rest of the criteria can be handled the same, and a diagnostic test for depression looks more similar to the NEO PI-R than the interviews we imagine from watching the movies.

Interrater reliability on psychiatric evaluation is not very low, but it’s not perfect, where an objective test would be perfect. So why do we not make psychiatric diagnostic tests out of the criteria we have? Some of the answers are based on gut feelings: who would want to be diagnosed as being schizophrenic after filling out a simple questionnaire? Not only that, but what would psychiatrists’ experience be worth? And yet we know that experience does not lead to more accurate diagnoses, nor do more complicated methods of summating data. The answers to this question need to be logical. And few can be found. The DSM-V focused on simplifying diagnosis, on making the “art” less subjective. Can we expect that by the DSM-VIII, every diagnosis will be based on a short questionnaire or something similar?