In Chapter 1, we presented 3 axioms of mental health care for medical settings: (1) The comorbidity of medical and mental disorders is frequent; (2) chronic physical symptoms are a common presentation in patients with a mental disorder; and (3) chronic physical symptoms may be due to medical disease and/or medically unexplained symptoms (MUS).

Because physical symptoms are prominently associated “red flags” for mental disorders, we now address the diagnostic approach to them, with the understanding that all physical disease problems are not associated with a mental disorder. One caveat is that patients occasionally present only with psychological symptoms. In that case, we of course proceed directly to develop the details needed to establish a mental disorder diagnosis, as outlined in later chapters. In most instances, however, physical symptoms are so common that they usually are considered first, then inquiring about psychological symptoms when you can better focus on a possible mental disorder.

You may say that you already know medical diagnostics; after all, that’s what has been emphasized throughout your medical training. Here’s the problem. There can be diagnostic uncertainties when the symptoms are difficult to explain in MUS. Consequently, we will provide guidelines for evaluating physical symptoms that will allow you to comfortably expand your evaluation to the psychological realm without worrying that you have missed some physical disease. We now address the medical diagnostic approach in the presence of prominent physical symptoms. In later chapters, we address how to diagnose the psychological symptoms needed to make a specific mental health diagnosis.

We have defined a mental disorder as a mental or substance use disorder. We define a disease as a disorder included in current classifications of diseases (eg, editions of the International Classification of Diseases).^1,2 These are the diseases you might find listed in medical textbooks, characterized by a unique pathophysiologic basis.

Medically unexplained symptoms are the opposite—physical symptoms with little or no disease or pathophysiologic explanation, also referred to as somatization or somatoform disorders. Patients who have an organic disease can also have MUS when the symptoms are not attributable to the disease or are out of proportion to what would be expected. MUS poses a far greater diagnosis problem for clinicians, so we address it in detail.

The Diagnostic and Statistical Manual of Mental Disorders (DSM) has provided an influential classification. DSM-4 defined the following MUS disorders in the somatoform category: somatization disorder, undifferentiated somatoform disorder, conversion disorder, pain disorder, hypochondriasis, body dysmorphic disorder, and somatoform disorder not otherwise specified.³ While useful for research, none had sufficient validity to use clinically nor were they comprehensive enough to capture more than a few of the chronic MUS patients commonly seen in medical settings.^4,5 Widespread dissatisfaction led to a change where many of the DSM-4 disorders were combined into what is now called somatic symptom disorder in DSM-5.⁶ Not validated, it has been criticized for being too sensitive and lacking specificity.^7-11 Moreover, the complex criteria of both DSM-4 and DSM-5 have further discouraged the use of these diagnoses by medical clinicians. Rather, clinicians have developed medical names for MUS syndromes, for example chronic pain (low back, neck, head), fibromyalgia, irritable bowel syndrome, nonulcer dyspepsia, and chronic fatigue syndrome.¹² Indeed, almost every body system has one or more disorders characterized by its specific type of MUS. Multiple efforts to demonstrate that some of these MUS subsets are actually a true disease (with a pathophysiological basis) have been unsuccessful, and the various entities also lack validity because of overlapping criteria.¹³

Because you already are well trained in physical diseases, we do not address medical diagnosis (or treatment) here. We assume this familiarity in our frequent references to integrating mental health and disease care. That is, you conduct your diagnostic approach to making a disease diagnosis the same way you always do.

We focus here on evaluating the physical symptoms of chronic MUS. We have not found the somatic symptom disorder criteria of DSM-5 or the multiple DSM-4 somatoform diagnoses helpful for the reasons given previously. We do, however, embrace the DSM-4 approach requiring exclusion (ruling out) of a disease explanation before making a diagnosis of MUS. Because of Western medicine’s long use of a disease-based classification system, we believe the only logical way to diagnose chronic MUS is to first exclude (rule out) disease.^14,15

Chronic MUS is extraordinarily prevalent. Approximately 10% of clinic patients have chronic MUS.^14,16 Their clinical picture (and diagnostic evaluation) is summarized in Table 2-1.

Physical Symptom Profile

Most commonly, symptoms are ill defined and are related to the musculoskeletal, gastrointestinal, cardiopulmonary, and nervous systems, although any system may be involved.^14,17-20 Pain often is the most prominent symptom and can occur anywhere but is most likely in the low back, neck, head, pelvis, chest, and joints.¹⁹ Nonpain complaints include fatigue, constipation, diarrhea, and bloating. Symptoms often occur in combination and may fit published patterns of known syndromes, for example fibromyalgia, chronic fatigue syndrome, or irritable bowel syndrome. Importantly, worrisome symptoms suggesting an organic disease, such as fever, sciatica, angina, or weight loss, are usually not present. While the physical symptoms may be intermittent in less severe instances and occur only in relationship to stressful events, most of the time symptoms are continuous and independent of life stresses, although often worsened by a new stress. In obtaining the longitudinal history, patients may report what seemed initially to be a minor illness, but one that did not clear and became chronic MUS. A common history is acute back pain that did not remit, often continuing to receive prescription opioids for the pain and eventuating with chronic, progressively more severe MUS. On other occasions, chronic MUS may follow a respiratory infection or gastroenteritis. Especially troubling to the clinician who fears missing a disease diagnosis are patients who have had a serious disease and who, once resolved, continue having the same symptoms without recurrence of the actual disease, for example recurrent chest pain not due to coronary insufficiency following a myocardial infarction.¹⁴

Psychological Symptom Profile

While we have emphasized that psychological symptoms may not be prominent, they are nonetheless usually present and typically bespeak an underlying mental disorder. Outlined in detail in later chapters, symptoms of depression and anxiety are frequent and almost universal in the high care-utilizing and disabled MUS patient.⁴ In many, prescription substance misuse also occurs. Also, symptoms of posttraumatic stress disorder (PTSD) may be present, especially in patients who have a history of some type of abuse.^21-23 Similarly, family structures may have been insecure, current relationships are often frayed, and lifestyles are sometimes chaotic.²² Further, because of the severity of their disability, job performance may be spotty and many are not employed, often on disability support.