Oliver Howes provides the medical background to a seemingly very common condition

"For each ailment that doctors cure with medications (as I am told they do occasionally succeed in doing) they produce 10 others in healthy individuals by inoculating them with that pathogenic agent 1000 times more virulent than all the microbes--the idea that they are ill."
Marcel Proust, The Guermantes Way

Hypochondriasis is common in primary care and general hospital settings. The diagnosis is frequently missed, and it causes considerable morbidity and a large burden to health services. Transient hypochondriasis has been reported in 70% of medical students. The definition of hypochondriasis is a persistent, unrealistic preoccupation with the possibility of having a serious disease. Common, normal sensations and appearances are often misinterpreted as abnormal and signs of disease. The diagnostic criteria for hypochondriacal disorder in the ICD-10 (international classification of diseases, 10th revision) require the following to be present¹:
   ^* persistent belief in the presence of at least one serious physical illness underlying the presenting symptom or symptoms; and
   ^* persistent refusal to accept the reassurance of several different doctors that there is no physical illness.

The criteria defined in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), include the additional qualifiers that the preoccupation lasts at least 6 months and causes clinically significant impairment or distress.² The belief should not be delusional in intensity. It is almost unique in medicine as it is a diagnosis that requires other doctors to have seen the patient and failed to reassure him or her; the first doctor to see the patient cannot make the diagnosis. Epidemiological evidence suggests that this diagnosis is not made often enough.

Background

The term hypochondriasis has a long and complex history. It derives from hypochondrium ("below the cartilage"), an anatomical description for the abdominal area below the ribs first used by Hippocrates in the fourth century BC. "Humours" (fluids) presumed to be emanating from the hypochondrium were thought to cause disturbances in the psyche and soma and lead to disease.³ In the 18th century, "hypochondria" was referred to as the "English malady," because it was said to be so common in England, and was linked to disorders of many organs, particularly the spleen and uterus.⁴ The many famous sufferers include Immanuel Kant, Beethoven, and Samuel Johnson. Charles Darwin began a lifetime of suffering as a medical student. "Hypochondriac," derived from the same root as hypochondriasis, has acquired pejorative connotations and become associated with malingering. These connotations should, however, not be attached to hypochondriasis, which is a distinct medical condition associated with considerable suffering. Hypochondriasis is used as a term both for a symptom describing fears of illness and for a distinct condition.^{5 6}

Classification

Hypochondriasis traditionally fits into the group of neurotic disorders. The extent to which hypochondriasis overlaps with these other disorders is subject to ongoing debate.^{1 2 6} The ICD-10 category of somatoform disorders includes somatisation disorder, and somatoform autonomic dysfunction as well as hypochondriacal disorder. The table highlights the main differences between the disorders. Patients, however, often have somatic symptoms as well as worries about disease. The somatoform disorders may be best thought of as a continuum, with fear of serious disease at one end and preoccupation with somatic symptoms at the other.

Hypochondriasis may be primary when it exists independently from other psychiatric conditions. Hypochondriacal symptoms, however, are often secondary to other conditions such as depression, anxiety disorders, and delusional disorders. Treatment should be only for the primary disorder; secondary hypochondriacal symptoms will usually resolve as the primary disorder is treated. Shortlived hypochondriacal ideas are common in the general population, particularly in patients who have just received a medical diagnosis with a poor prognosis. Forms of hypochondriasis have been described in specific subpopulations. Hypochondriacal concerns are reportedly associated among people in certain occupations; these occupations include actors, musicians, doctors, and medical students.⁴ Although the reports of hypochondriacal concerns in these occupations are largely based on anecdotal reports, the association of shortlived hypochondriacal reactions with medical students has been more formally studied. Transient hypochondriacal concerns seen in these groups and the general population, however, are clearly distinct from ICD-10 hypochondriacal disorder in form and severity.
 

"Medical studentitis"

Clinical teachers have long reported that medical students frequently develop groundless fears and symptoms of illness.⁷ This has been termed "medical student's disease," "hypochondriasis of medical students," "nosophobia," and "medical studentitis."⁸ Such reactions rarely reach the strict ICD-10 or DSM-IV criteria for hypochondriasis.⁹ The reactions are often comparatively shortlived, although repeated, and associated with a disease being studied at the time (box 1).

There has been little research into this phenomenon, although early studies suggest that 70-80% of medical students experienced it.^{7 8} These studies were uncontrolled and based on case records or small samples. Less than 1% of the students displayed "true hypochondriasis."

The first controlled study matched medical students with law students (60 in each group) for age and sex.¹⁰ Responses to questionnaires assessing hypochondriacal concerns were compared. The medical students attended to their health and somatic symptoms more, but there was no significant difference in the prevalence of hypochondriacal tendencies. Law students are highly selected, however, and may not be a good comparison group. More recently, a controlled study in the United Kingdom assessed rates of hypochondriasis in clinical medical students and compared them with other students and the general population.⁹ Sixty per cent of clinical students replied. The medical students showed non-significantly lower rates of hypochondriasis than the other students and non-students.

These results question the widely held view that medical students are more hypochondriacal than others. Two factors may have resulted in this idea. Firstly, the phenomenon of hypochondriasis in trainee doctors may receive more attention from tutors and student doctors than the same phenomenon in, say, a history student. Secondly, early claims of very high prevalence in uncontrolled studies may have resulted in selective attention and a lowered threshold for recognition of the phenomenon.

Epidemiology

Most healthy people--60-80% in studies--experience somatic symptoms regularly.¹¹ It is likely that only a very small proportion of these would meet the full diagnostic criteria for hypochondriasis. In primary care settings in 14 countries throughout four continents, 0.5-1.0% of patients meet the ICD-10 criteria for hypochondriasis.¹¹ About 2.2% meet criteria for an abridged version that is based on all the major criteria except the failure to accept medical reassurance.^{11 12} Many of these patients go on to be seen in general hospitals. The prevalence of hypochondriasis in general medical clinics has been reported at 4.2-13.8%.¹³ There are no clear differences of sex, age, or geographical location in the prevalence of the condition.

Aetiology

Physiological, psychological, and sociological factors are implicated in the cause and maintenance of hypochondriasis. There is little firm evidence of specific genetic factors. Hypochondriacal patients may be more prone to anxiety and tend to perceive their bodily functions more accurately than others.¹¹ The emotional arousal associated with anxiety may lead to physiological changes and increased activity in the autonomic nervous system, endocrine changes, and even biochemical disturbances--for example, hypocapnia following hyperventilation. These may cause or increase somatic symptoms.¹⁴

Maladaptive behaviours, such as bodily checking, feed into the cycle of anxiety, leading to greater arousal and increased symptoms. For example, a man who feared that he had testicular cancer repeatedly checked his testicles. This caused testicular pain, which he interpreted as the early signs of cancer and led to increased checking.

The reactions of others may serve to establish and maintain behaviour.⁶ A number of childhood experiences, especially of illness, may predispose individuals to develop hypochondriasis. Adult hypochondriasis has been found to be associated with the following childhood experiences¹⁵:
   ^* serious or chronic medical illness in the individual or family members;
   ^* being sick and missing school; and
   ^* traumatic experiences, particularly physical and sexual trauma.

Certain parental characteristics may predispose children to develop hypochondriasis as adults. In particular, parental overprotectiveness, neuroticism, and selective responses to physical complaints, such as showing more sympathy and being more likely to call the doctor when the child was ill, are more common in patients with hypochondriasis than controls.¹⁶ Interestingly, although medically unexplained symptoms in childhood may be a precursor to those symptoms in adulthood, the largest follow up study to date found they were more strongly associated with psychiatric disorder generally, such as depression and anxiety, than physical symptoms.¹⁷

Course and prognosis

Hypochondriasis is considered to be a chronic, stable condition that causes long term disability, and this is supported by a recent prospective case control study.¹⁸ Over 200 subjects and controls were recruited from the medical outpatient department in a big teaching hospital. At follow up, 4-5 years later, there had been an improvement in hypochondriacal symptoms, but two thirds of the patients still met diagnostic criteria.

Morbidity and cost

Patients with hypochondriasis suffer considerable emotional and psychological stress, and impairment of social and occupational functioning. In a general practice sample they were at least twice as likely to have moderate to severe occupational disability than patients without hypochondriasis.¹² They were also nearly three times more likely to be referred for further investigation. They show as much or more impairment on standard physical functioning scales than patients with chronic conditions such as diabetes or arthritis, and are limited to bed two to three times more than patients with most major medical illnesses.^{18 19}

Where the diagnosis is not made, they can suffer major iatrogenic morbidity. There is a risk of complications from investigations, and side effects from symptomatic or inappropriate treatments. Both severe cases and less extreme cases illustrate the considerable morbidity and the resource burden on health services (box 2).²⁰ A study focusing on "mild" cases found that somatising patients had mean annual medical costs of US $3185 (£2016).¹⁹
 

Treatment

The treatment of hypochondriasis has traditionally been difficult. Where it is secondary to another condition it usually resolves with treatment of the primary disorder. For example, hypochondriasis which is secondary to depression will usually resolve when the depression is successfully treated.

Recognition and early diagnosis are important. Reassurance, combined with a serious appraisal of symptoms and an explanation of psychological factors may then be effective.^{5 6} It is not enough simply to tell the patient that there is nothing wrong. It is important to acknowledge the patient's distress and provide an alternative model, introducing psychological factors. A dismissive attitude that "it is all in your head" is counterproductive.⁶ Management regimes based on regular, brief appointments with one key doctor, and avoiding admissions to hospital are useful. They have been found greatly to improve physical functioning and cut costs on investigations and hospital admissions by one third.¹⁹

Various drug treatments and talking therapies are beginning to be evaluated with controlled trials. Even in chronic cases 50% of patients improve with treatment.¹¹

Psychotherapies (talking therapies)

Models have been developed for use in primary care based on understanding, and reattribution of symptoms and associated worries to a psychological explanation.⁶ Anxiety management techniques, and other behavioural treatments have also been used, but the best evidence is for cognitive behavioural therapy.²¹ This was developed to treat depression but subsequent trials have shown its efficacy in many psychiatric conditions. It is a structured therapy based on a scientific model that aims to alleviate psychological problems and improve coping skills. Cognitive behavioural therapy for hypochondriasis addresses both the thoughts and the beliefs (the cognitive element) that the patient has about bodily sensations and illness, and the associated behaviours (the behavioural part). Maladaptive automatic thoughts and assumptions are worked upon, such as "all bodily sensations are signs of serious illness" and "if I don't worry about health I'll get a serious illness." Perpetuating behaviours, such as repeated checking for symptoms or reassurance seeking, are identified and alternative behaviours developed and tested by the patient and therapist. Patients given cognitive behavioural therapy show significant improvements, up to 80%, on a number of indicators of hypochondriasis compared with controls.²²

Pharmaceutical treatment

Case reports suggest tricyclic antidepressants are helpful.²³ There is better evidence for the efficacy of selective serotonin reuptake inhibitors. Preliminary results from a controlled trial indicate a better response to fluoxetine (66.7% virtual remission) than placebo (50%), although the placebo effect is large.²⁴

Conclusion

Hypochondriasis is common and can cause considerable distress, iatrogenic illness, and costs to health services. Diagnosis is often delayed, which exacerbates the condition. Greater awareness and the expansion of liaison psychiatry should correct this. There is growing evidence for the efficacy of treatments, particularly for cognitive behavioural therapy and selective serotonin reuptake inhibitors. Finally, it seems that medical students are not any more hypochondriacal than the general population. So you have one less thing to worry about.