DEFINITION

• Illness anxiety disorder is characterized by excessive anxiety and consuming preoccupation with illness in the absence of physical symptoms or when only mild physical symptoms are present.

• Illness anxiety disorder is classified under the Somatic Symptom and Related Disorders section of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)[1].
  • Other diagnoses under this section include somatic symptom disorder, conversion disorder, and factitious disorder.
  • Illness anxiety disorder replaces the DSM-IV-TR[2] diagnosis of hypocondriasis.
  • Although illness anxiety disorder is listed under the Somatic Symptom and Related Disorders section of the DSM-5, it is also conceptualized as an anxiety disorder.
• When considering this diagnosis, it is important to have a firm understanding of somatization.
  • Somatization is the expression of mental phenomena as physical (somatic) symptoms.
  • There is a continuum of unconscious/non-volitional display of symptoms (patient unaware of the non-physiologic nature of symptoms) to conscious/volitional display (patient aware of the non-physiologic nature of symptoms).
  • Also important is the difference between primary gain (positive internal motivations) vs. secondary gain (positive external motivations).
    
    • Primary gain example: A patient feels guilty about not being able to perform a task, but if there is a medical condition justifying this inability, the guilt diminishes.
    • Secondary gain example: A patient is allowed to miss work and gets financial compensation as the result of a medical condition.
    • Any given patient with illness anxiety disorder will have primary and/or secondary gains associated.