When I meet new people, they often tell me about someone they know that has some sort of emotional problem. Many people give me a synopsis of symptoms and ask whether or not a person has obsessive compulsive disorder, anxiety, attention deficit disorder, depression, or borderline personality disorder. I’m pretty quick to say that I don’t ever make a diagnosis without seeing a person, but can talk about some qualities that might suggest this or that. I almost always point out that emotional problems are different than physical ailments; they tend to be more dimensional and less categorical. At this point, most people are stifling a yawn and moving on to the next topic (or in your case blog).

But our blog readers tend to be persistent, so let me continue. In the medical model, which psychology too often tries to emulate, a person has a disease and that disease can, in most cases, be verified by a medical test. For example, your biopsy reveals cancerous tissue or your blood test suggests that you have been invaded by parasites. Or the sore throat, fever, and a positive culture are consistent with a diagnosis of strep throat. Good medical diagnosis then hopefully leads to specific, specialized treatment.

The diagnosis of mental disorders is not so black and white. You don’t catch depression. And the symptoms of depression can look very different among people. Some with depression sleep too much or eat too much. Some toss and turn all night and lose their appetite. Some weep; others rage. There’s no blood test or MRI for assessing a diagnosis of depression. And unlike pregnancy, you can be just a little anxious or depressed.

The same diagnostic issue is even truer for what are known as the personality disorders. For example, the diagnosis of Obsessive Compulsive Personality Disorder (which is different than the more commonly known, Obsessive Compulsive Disorder) requires a person to demonstrate four of the following eight symptoms (according to the DSM IV TR):

  • Preoccupation with details, rules, and lists
  • Perfectionism that interferes with finishing projects
  • Unable to throw away worthless objects
  • Unable to delegate tasks
  • Miserly spending
  • Inflexible, scrupulous over conscientiousness
  • Devotion to work to the exclusion of leisure and friendship
  • Stubborn and rigid

The criterion for this diagnosis means that two people could both have a diagnosis of Obsessive Compulsive Personality Disorder without having a single symptom in common. Other personality disorder categories have similar problems. For example there can be something like 250 different symptoms clusters for people with Borderline Personality Disorder.

Furthermore, in psychology, diagnoses change with culture and time. We aren’t suggesting that mental health diagnoses are useless. They do ease communication and provide hints as to treatment and prognosis. But they are quite limited and fail to capture the richness of each individual. The field has a long way to go in improving its diagnostic procedures. In the meantime, it’s the best we have. Future efforts are being made to try and view the various diagnoses on a continuum (that is, dimensionally) rather than discrete, black and white categories.