somatization disorder

Problems with the diagnosis of somatization disorder

What is somatization disorder?

Somatization disorder is a psychological disorder (listing 300.81 in the DSM-IV, the Diagnostic and Statistical Manual of Mental Disorders). It is a variety of somatoform disorder, a condition in which a patient reports physical symptoms which cannot be explained by a known general medical disorder. These symptoms must be significant enough to cause distress and impair the person's functioning.

The diagnostic criteria

The diagnostic criteria for somatization disorder require a history of multiple physical complaints beginning before age 30 which resulted in seeking treatment or impaired functioning.

Furthermore, there must be symptoms in each of several categories: four pain, two gi, one sexual, and one pseudoneurological(other than pain). These symptoms must be unexplained by appropriate medical investigation.

According to the DSM-IV, studies have reported incidence rates for somatization disorder from .2% to 2% among women and less than .2% in men. Since the condition can impair occupational functioning, somatization disorder may have a significant economic impact.

Undifferentiated Somatoform Disorder

If a somatoform presentation does not meet the full criteria for somatization disorder, the DSM-IV provides for a diagnosis of undifferentiated somatoform disorder. This describes a patient with one or more physical complaints that persist for 6 months or longer. The most frequent are chronic fatigue, loss of appetite, or gastrointestinal symptoms.

According to the DSM-IV(pp.451) the eventual diagnosis of a general medical condition or another mental disorder is frequent.

Problem with diagnosis by exclusion

Undifferentiated somatoform disorder and, to a lesser degree, somatization disorder, are diagnoses of exclusion. That is, a conclusion is made by ruling out other possibilities, rather than proving the conclusion.

Medicine is an incomplete science; new adverse drug reactions, environmental exposures, and disease conditions appear which were previously unknown. Fibromyalgia, lyme disease, H.pylori infection, SARS, and HIV infection are examples. As new drugs enter widespread use, new adverse drug reactions are also discovered. Known diseases also can present themselves in unusual ways. In the real world, symptoms with a medical cause might not fit a known general medical disorder, yet they are not psychological. In addition, doctors can make a mistake, and fail to diagnose a recognized condition.

The diagnostic criteria for somatoform disorders do not account for this. They presume medicine is a complete science and doctors never make mistakes.

If a patient's symptoms are not recognized because of the incomplete nature of medical science, or because of an inadequate medical evaluation, it doesn't mean a mental disorder exists. Yet this is how the diagnostic criteria for somatoform disorders work. There is no allowance for a middle ground, in which a doctor says "we don't know what's wrong".

In rhetoric, this flaw in reasoning is called an appeal to ignorance, which justifies a conclusion based on lack of proof of something else. The corollary to this is that "absence of proof is not proof of absence".

If a patient has mental symptoms(such as an altered mood), but for which there is no recognized psychiatric disorder, does that prove they have a physical illness? Not necessarily. Medicine is such a complex science, it's inability to clearly recognize the cause of a patient's symptoms should not logically result is concluding there is no physical cause. Below are examples of "appeals to ignorance":

What should be done?

The existence of a mental disorder should be proven based on direct evidence, not the absence of proof of a known physical disease. Physicians should say "I don't know" when they can't make a diagnosis, instead of discounting symptoms they can't (easily) explain.

Significance to those with chronic candida

A nine page article was published in 1991 on the potential for misdiagnosing people with chronic candida as having somatization disorder1. Unfortunately, this is the only officially acceptable course of action at present. Chronic candida cannot become a recognized condition until there is research that defines it. However, the current lack of research doesn't mean the condition has been disproven.


  1. Cater RE II "Somatization Disorder and the Chronic Candidiasis Syndrome: A Possible Overlap" Medical Hypothesis(1991) 35126-135

This page last modified 2023-04-30