Functional Disorders in Medicine

Functional Disorders

• Functional disorders are conditions where an individual experiences somatic symptoms that affect daily functioning or quality of life, and cannot be better explained by another physical disease or psychiatric disorder.
• These disorders are often referred to as "thick folder patients" or frequent attenders.

Functional Somatic Syndromes Across Specialties

• Gastroenterology: Irritable bowel syndrome (IBS), non-ulcer dyspepsia
• Gynaecology: Pelvic arthropathy, premenstrual syndrome, chronic pelvic pain
• Rheumatology: Fibromyalgia, lower back pain
• Cardiology: Atypical or non-cardiac chest pain, syndrome-X
• Respiratory medicine: Hyperventilation syndrome
• Infectious diseases: Chronic fatigue syndrome (CFS, ME), Chronic Lyme disease
• Neurology: Tension headache, non-epileptic seizure
• Dentistry: Temporomandibular joint dysfunction, atypical facial pain
• Ear, nose and throat: Globus syndrome

Common Characteristics of Functional Somatic Syndromes

• Diagnoses are based solely on patients' reports of subjective complaints
• No true biomarkers or paraclinical tests can objectively verify the diagnoses
• Complaints are mainly unspecific symptoms that are common in the general population

Diagnostic Constructs

• Symptoms or symptom count
• Phenotype-symptom pattern/illness picture
• Psychological and behavioural characteristics
• Assumed aetiology (e.g. Central Sensitivity Syndrome)

Bodily Distress Syndrome (BDS)

• Suggested diagnostic criteria: • Types: Multi-organ type (≥3 symptoms from 3-4 organ systems), Single-organ type (≥3 symptoms from 1-2 organ systems) • Symptoms are distressing or cause substantial distress • Relevant differential diagnoses have been ruled out • Duration > 6 months

Bodily Distress Syndrome (BDS) Symptoms

• Cardiopulmonary/autonomic arousal symptoms: ≥3 symptoms (e.g. palpitations, heart pounding, precordial discomfort, breathlessness without exertion, etc.)
• Gastrointestinal arousal symptoms: ≥3 symptoms (e.g. frequent loose bowel movements, abdominal pains, feeling bloated, etc.)
• Musculoskeletal tension symptoms: ≥3 symptoms (e.g. pains in arms or legs, muscular aches or pains, etc.)
• General symptoms: ≥3 symptoms (e.g. concentration difficulties, impairment of memory, fatigue, etc.)

Central Sensitization

• Amplification of neural signaling within the CNS
• Prolonged response leads to a pathological state characterized by a dysfunctional response to different and normally non-noxious stimuli, manifesting as pain hypersensitivity

Etiology of Functional Disorders

• Vulnerability: Biological, psychological, and social heritage, social learning, previous illnesses, sexual abuse
• Triggering factors: Infection or other diseases, physical or psychological trauma, stress or strain
• Maintaining factors: Dysfunctional beliefs about symptoms and illness, dysfunctional illness behavior, hypersensitization and/or dysfunctional processing of symptoms in the CNS, social and economical dependence

Historical Background and Changes from DSM III to DSM 5

• Somatoform Disorder was first introduced 30 years ago in DSM-III
• DSM-IV introduced the concept of medically unexplained symptoms
• DSM-5 replaced Somatoform Disorder with Somatic Symptom Disorder and Related Disorders