The latest edition of DSM 5 has moved away from the need to have no medical explanation in order to make the diagnosis of ‘medically unexplained symptoms’ and gain access to appropriate treatment. The emphasis now is on symptoms that are substantially more severe than expected in association with distress and impairment. The diagnosis includes conditions with no medical explanation and conditions where there is some underlying pathology but an exaggerated response.
‘The major diagnosis in this diagnostic class, Somatic Symptom Disorder, emphasises diagnosis made on the basis of positive symptoms and signs (distressing somatic symptoms plus abnormal thoughts, feelings, and behaviours in response to these symptoms) rather than the absence of a medical explanation for somatic symptoms. A distinctive characteristic of many individuals with somatic symptom disorders is not the somatic symptoms per se, but instead the way they present and interpret them.’(APA, 2013)
A new category has therefore been created under the heading ‘Somatic Symptom and Related Disorders’. This includes diagnoses of Somatic Symptom Disorder, Illness Anxiety Disorder, Conversion Disorder, Factitious Disorder, and a variety of other related conditions. The term ‘Hypochondriasis’ is no longer included. In two of the conditions the absence of any medical pathophysiology is a criteria for diagnosis; these are Conversion Disorder and Other Specified Somatic Symptom and Related Disorder (which includes Pseudocyesis, a false belief of being pregnant that is associated with objective signs and reported symptoms of pregnancy).
The diagnostic criteria for Somatic Symptom Disorder noted in DSM 5 are:
With predominant pain (previously pain disorder): This specifier is for individuals whose somatic symptoms predominantly involve pain.
Persistent: a persistent course is characterized by severe symptoms, marked impairment, and long duration (more than 6 months).
Mild: Only one of the symptoms specified in Criterion B is fulfilled.
Moderate: Two or more of the symptoms specified in Criterion B are fulfilled.
Severe: Two or more of the symptoms specified in Criterion B are fulfilled, plus there are multiple somatic complaints (or one very severe somatic symptom).
The expected prevalence of Somatic Symptom Disorder stated in DSM 5 is higher than that for Somatization Disorder (<1%) but lower than that of Undifferentiated Somatoform Disorder (19%). Both are more common in women. Nevertheless, the term Somatic Symptom Disorder is considered by DSM 5 to be broadly equivalent to ICD10 F45.1 and ICD9 300.82 Undifferentiated Somatoform Disorder, and includes most patients with Hypochondriasis ICD 10 F45.21 and ICD 9 300.7.
The diagnostic criteria for Illness Anxiety Disorder noted in DSM 5 are:
Care-seeking type: Medical care, including physician visits or undergoing tests and procedures, is frequently used.
Care-avoidant type: Medical care is rarely used.
The important distinction between Illness Anxiety Disorder and Somatic Symptom Disorder is that with the former, the individual’s distress emanates not primarily from the physical complaint itself but rather from his or her anxiety about the meaning, significance, or cause of the complaint. DSM 5 considers the prevalence over 1-2 years to be between 1.3 and 10% of populations, and 6-month to 1 year prevalence to be between 3 and 8%. Illness Anxiety Disorder encompasses those patients with Hypochondriasis, ICD 10 F45.21, ICD 9 300.7 who do not have somatic symptoms.
The diagnostic criteria for Conversion Disorder noted in DSM 5 are:
Specify symptom type:
With weakness or paralysis
With abnormal movement
With swallowing symptoms
With speech symptom
With attacks or seizures
With anesthesia or sensory loss
With special sensory symptom
With mixed symptoms
Acute episode: Symptoms present for less than 6 months.
With psychological stressor: (specify stressor).
Without psychological stressor.
Terminology can get confusing when clinicians are describing Conversion Disorder. The concept is often considered so difficult to address with the patient, and much terminology inherently pejorative, that physicians may choose obscure terminology to avoid any appearance of directly challenging the patient. Some will choose ‘psychogenic’, while others chose the more neutral ‘functional’ (as in abnormal central nervous system function). The term ‘functional disorder’ is not the same as ‘functional overlay’ which applies to exaggeration of symptoms as seen in Somatic Symptom Disorder and Factitious Disorder.
The diagnosis only includes symptoms of a central neurological disorder when clinical findings demonstrate clear incompatibility with neurological disease. There are many classical examples where an individual shows and describes obvious disorders, but when observed at other times or when tested in other ways, they are clearly normal (such as weakness or absence of plantar flexion when lying down, but the ability to walk on tip-toes when standing, or an apparent Grand Mal seizure while responding to commands). The diagnosis does not include disorders such as chronic pain, but Conversion Disorder may co-exist with Somatic Symptom Disorder. Co-morbidity with anxiety disorders and depressive disorders is common.
Conversion disorder is often associated with dissociative symptoms, and it is often associated with stressful life events and maladaptive personality traits. It is important to distinguish it from Factitious Disorder and Malingering. DSM 5 considers the prevalence to be around 5% of referrals to neurology clinics, with an annual incidence in the general population of 2-5/100,000.
Conversion Disorder is classified as ICD 10 F44.4-7 (depending on symptom type), ICD 9 300.11.
The diagnostic criteria for Psychological Factors Affecting Other Medical Conditions noted in DSM 5 are:
Specify current severity:
This diagnosis should be reserved for situations in which the effect of the psychological factor on the medical condition is evident, and the psychological factor has clinically significant effects on the course or outcome of the medical condition. Individuals who develop anxiety as a consequence of a condition should be diagnosed with Adjustment Disorder. While the prevalence is not clear, DSM 5 notes that it is more common than Somatic Symptom Disorder. The most frequently seen examples are likely to be avoidance of or poor adherence to treatment because of anxiety, and avoiding investigations when a serious condition is suspected.
Psychological Factors Affecting Other Medical Conditions is classified as ICD 10 F54, ICD 9 316.
The diagnostic criteria for Factitious Disorder noted in DSM 5 are:
Factitious Disorder Imposed on Self
Recurrent episodes (two or more events of falsification of illness and/or induction of injury)
Factitious Disorder Imposed on Another (Previously Factitious Disorder by Proxy)
Note: The perpetrator, not the victim, receives this diagnosis.
The essential feature is falsification of medical or psychological signs and symptoms. The diagnosis requires demonstrating that the individual is taking surreptitious actions to misrepresent, simulate, or cause signs or symptoms of illness or injury in the absence of obvious external rewards. It includes false reporting of facts such as symptoms, events, and investigation results. Individuals are at great risk of harm through inappropriate diagnoses and treatments, as well as from induced injury and disease. The condition is usually one of intermittent episodes. Persistent unremitting episodes, and single episodes, are less common. DSM 5 estimates the prevalence of 1% in hospital settings although it is very difficult to achieve an objective measure in a condition where deception is a key criterion. An important differential diagnosis is malingering, where there is personal gain such as financial gain or time off work. There needs to be an absence of obvious rewards in order to meet the diagnostic criteria.
Factitious Disorder is classified as ICD 10 F68.10, ICD 9 300.19.
DSM 5 notes that this category applies to presentations in which symptoms characteristic of a somatic symptom and related disorder that cause clinically significant distress or impairment in social, occupational, or other important areas of functioning predominate but do not meet the full criteria for any of the disorders in the somatic symptom and related disorders diagnostic class. Examples include:
These are classified as Other Somatoform Disorders ICD 10 F45.8, ICD 9 300.89.
DSM 5 reserves this category for rare occasions where there are predominantly somatic symptoms but there is insufficient information to make a more specific diagnosis. These are classified as ICD 10 F45.9 and ICD 9 300.82.
APA 2013. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Arlington, VA, American Psychiatric Association.