I like to think about diagnosis. It’s not a popular topic to discuss at parties, but I suppose it’s an appropriate thing for a psychologist to enjoy thinking about. Lately, I’ve been seeing a lot of misunderstanding online about psychological disorders like depression, anxiety, and even Borderline Personality Disorder (BPD).
When it comes to psychological diagnoses, many people are accustomed to seeing things from a medical model perspective. In medicine, disorders refer to identifiable “real” disease processes. But in mental health, there is often no germ, virus, or broken brain circuit to blame for psychological distress. As it turns out, psychological diagnosis is much more complicated than the common idea of “chemical imbalances.”
How Modern Diagnosis is Broken
Nowadays, diagnosis is focused on symptoms. If you’ve been experiencing things like
- a depressed mood for most of the day, nearly every day
- diminished interest or pleasure in activities
- trouble sleeping
- low appetite
- difficulties concentrating
and your symptoms have lasted for at least 2 weeks, then we call that Major Depressive Disorder. At first glance it makes sense: figure out which symptoms tend to go together and give that syndrome a name. Voila! You now have a disorder.
That’s just what the folks who created the Diagnostic and Statistics Manual of Mental Disorders (DSM) thought, too. But they started to run into trouble when the disorders included in the manual expanded from 106 in the original DSM-I…to 297 diagnosable mental disorders in the DSM-IV. Thankfully, they condensed it back down to 265 in the recently published DSM-5.
How can there be so many separate disorders? If you look under Major Depression alone, there are numerous modifiers: mild, moderate, severe, with psychotic features, in partial remission, in full remission, unspecified, with anxious distress, with mixed features, with melancholic features, with atypical features, with mood-congruent psychotic features, etc.
That’s not considering the numerous alternative depression diagnoses: Persistent Depressive Disorder (with numerous modifiers), Premenstrual Dysphoric Disorder, Substance-Induced Depressive Disorder, Depressive Disorder Due to Another Medical Condition, Other Specified Depressive Disorder, and Unspecified Depressive Disorder.
And that’s just for Depression. There are numerous other mood disorders (each with specific and nonspecific varieties), anxiety disorders, and many others.
Perhaps you can start to see the problem. When we diagnose based only on symptoms, we end up with a system where nearly every variation in symptom presentation becomes its own “disorder.”
But it wasn’t always this way.
Psychological diagnosis used to focus on hypothesized internal processes. For example, “depression” was thought to be the product of identifiable ways of thinking, feeling, and relating that – over time – produce the symptoms of depression. While we can debate the merits of individual theories, I think the overall approach was valid.
In the medical world, disorders are diagnosed based on identifiable underlying disease processes. Symptoms like headache, fever, and body aches can accompany numerous different diseases. In order to know which treatment to give, medical professionals need to identify the underlying cause of these vague symptoms – which is something at which medicine is getting very good because it deals with the physical world.
Mental health professionals aren’t so lucky. We treat subjective suffering. Recently, attempts have been made to turn psychology into a purely material science of the brain (Minds vs. Brains), but many agree that this is a flawed approach. Much of psychological suffering exists in the mind, which is an emergent property of the brain. Emergent properties are, by definition, not reducible to the parts that create them.
If we are to have a meaningful system of diagnosis, then it seems to me that we need to focus on both brains AND minds. We need to develop diagnoses based on underlying processes, not just observable symptoms.
For example, there is substantial evidence that depression comes in at least two varieties not listed in the DSM: one is based on interpersonal relationship issues, the other is based more on internal conflicts about self worth (here’s some research). Although they have similar symptom presentations, it is possible to tell the difference in therapy once the focus of a person’s thoughts and feelings becomes clear. Furthermore, there is evidence that these two depressions should be treated differently.
A Better Way
It comes down to a simple fact: we haven’t found the physical cause of most mental disorders (even the serotonin hypothesis for depression is in doubt), so we can’t really diagnose based on physical disease processes. But we also can’t diagnose based on symptoms alone, because it produces an unwieldy taxonomy of mental disorders that is both unhelpful and difficult to use. Such a system is great at telling us what a mental disorder looks like, but it can’t really tell us what one is. We need to find a happy medium that can connect symptoms with a comprehensible and testable model of underlying causes.
There are alternative approaches to diagnosing that are theory-specific and based on hypothesized underlying mental processes. One such example is the Psychodynamic Diagnostic Manual, which is broken into sections based on assessment of personality style, mental functioning, and symptom presentation. Such approaches make diagnosis comprehensible – both to clinicians and patients. Instead of “having” a disorder like a person “has” a cold, patients can be helped to understand the ongoing processes of thinking, feeling, and relating that produce distressing symptoms. Perhaps more importantly, such an approach empowers people to make positive changes in their lives to alleviate the symptoms they are experiencing.
Drawbacks to current theory-driven approaches include lower use among practitioners, less statistical support, and an arguable lack of validity (an experimental psychology term that refers to whether a construct really represents a real-world phenomenon) because they have been vetted by fewer studies. However, some systems (like the Psychodynamic Diagnostic Manual) are actually based on considerable and amply cited research.
Even with the admitted drawbacks of theory-specific diagnostic systems, many have the undeniable advantage of empowering clinicians and patients to ground present-day problems in a relevant historical/developmental context. The experiences that taught a person to think or relate in unhelpful ways can be understood, explained, and worked through.
Originally, the disorders listed in the DSM were designed to be a sort of short-hand that clinicians would use to communicate pertinent information about their patients. But to most people, the DSM has since become a compendium of reified, “real” disorders that can influence things like insurance reimbursement and a person’s ability to get hired for certain jobs. Moreover, receiving a psychological diagnosis can dramatically influence how patients come to think about themselves. As someone who has used both theory-driven and DSM diagnostic systems, I can say with confidence that we haven’t found a good balance yet.
So the next time you hear someone say that they “have” depression or anxiety – maybe think about what that really means. Language can either obscure or clarify. In the case of many modern day psychological diagnoses, it often does the former.
To read a more technical account of these issues, see here: Toward a Functional Understanding of Psychopathology: The DSM-IV-TR and Narcissistic Personality Disorder