The current iteration of the DSM has many problems, compounding the issues that psychiatric diagnosis has had for decades. The DSM blurs the differences between normal distress and the clinical levels of distress and dysfunction needed for diagnosis. Secondly, the goal of diagnosis is to allow for specificity— you need both a broadly defined category to describe heterogeneity within a categorization (depression, for example, looks differently at various points in development, in different demographic categories and individually) but specific enough to actually not be confused with another diagnosis entirely. Being inaccurate in diagnosis can lead to significant issues with treatment, especially seen as Bipolar Disorder can be confused with Major Depression, leading people to be prescribed an anti-depressant without a mood stabilizer, which may influence an onset of mania or hypomania (though that has not been entirely determined in the literature)
However, one of the biggest problems with this diagnostic challenge is that because of the need for heterogeneity, many symptoms occur across diagnostic categories. Compounding it, the symptoms that are meant to make distinctions among diagnoses are themselves incredibly vague and difficult to quantify. Even specifiers are different and somewhat subjective—for example, determining mild vs moderate depression is not that clear cut and can vary from person to person, despite the attempt to establish criteria between the two. It can lead to issues of diagnostic creep and diagnostic inflation, both which can lead people to be diagnosed incorrectly because vagueness leads people to diagnose according to their own previous biases. It means that often people who are more likely to specialize and study bipolar disorder may see bipolar disorder everywhere , which can account for increases among certain diagnostic categorizations.
So how does this affect the individual being diagnosed? Well, what many people experience is that diagnoses change throughout people's lifetime and in fact, may change from practitioner to practitioner, not reflecting someone's competence in diagnosing but rather the problem of diagnosing itself.
As an example, I will use myself as a case study. Perfect for a navel gazer like myself. Throughout my life I have held the following diagnoses: Bipolar I, Bipolar II, Cyclothymia, Generalized Anxiety Disorder, ADHD, Depressive Disorder NOS (now would be unspecified under new diagnostic categorizations) and PTSD. Now, while some of this, especially around the change from the PTSD diagnosis accounts for the fact that certain symptoms have been extinguished the multiple lifetime diagnoses still speaks to the problem of the same symptoms being interpreted differently due to the vagueness of diagnosis and so I will break this down a little bit.
My central issue is mood dysregulation. There is likely a gene x environment interactive effect that has caused it. I experienced significant trauma in development, which has caused a certain base level of hyperarousal (state became trait in my developing brain). I also have some genetic vulnerability as can be seen that throughout my family exists an spectrum of mood and psychotic disorders. There is definitely a degree of genetic loading.
So what does this mean in terms of diagnosis? Well, let's look at a couple of problems in terms of how they may be interpreted. If it seems confusing, it is.
1. Irritability and hyperarousal: Depending on the interpretation, the irritability, combined with issues of reduced sleep, ruminations and hyperarousal, may be interpreted as a mixed episode. Previously considered only part of Bipolar I, now there is more of a sense that mixed features can be seen across all categorizations of Bipolar Disorder and also Major Depression. The idea is that I had both manic and depressive symptoms at the same time, causing a dysphoric mania that appeared to be a potent mix of self destruction and acting out.
You know—maybe. But then again, maybe it's not a mixed episode at all. Irritability is major part of depression and combined with significant anxiety, can be give dysphoria this ruminative flavor that someone may consider racing thoughts. Maybe. Even if it is a mixed episode, now given the changes in criteria—is it Bipolar I or II? And for that matter—telling the difference between mania and hypomania isn't that easy. You get occasional slam dunks but particularly when you get intense irritability, it's not that easy to see how severe it is. Boundaries between diagnostic categories are much fuzzier than it might seem from the outside. And then there is the question about whether the problems I have with irritability and dysregulation are even clinically significant, because if it doesn't interfere with aspects of my life—even if the symptoms are present—it isn't considered clinically significant and therefore doesn't meet the criteria for any psychiatric disorder. What does clinical significant distress even mean? And how is that different from more normative problems, even if due to dysregulation?
2. Lack of concentration: This occurs among many diagnoses—ADHD, PTSD and Depression—> it depends how you interpret the origins of the symptoms. I could argue that I had a neurocognitive issue that required stimulants to concentrate. I had the hyperactivity. I had a very extensive evaluation indicating that I met the criteria, especially when combined with my issues with sleep. But then again, I wonder if it is due to the hyperarousal and anxiety, making persistent in difficult tasks a challenge and needed perpetual feedback to manage and contain my emotions.
But it is going to continue to be a challenge, not just for people seeking help but for the helpers to be able to navigate with a manual that is vague that is guided by people's self interest (and fights over diagnostic categorizations because of various power player's specialization) and research which can often have its own issues with validity and reliability.
If you want to read more, I'd encourage you to read Frances Allen, particularly this book or his series for Huffington Post. He is no outsider making questionable critiques like Szasz but someone who has a vested interest in making responsible diagnosis and makes a thoughtful inquiry into the current issues we have with diagnosis.