A scheme for thinking about the aetiology of functional symptoms in neurology
| Factors | Biological | Psychological | Social |
|---|---|---|---|
| Predisposing | • Genetic factors affecting personality | • Poor “attachment” to parents and others | • Childhood neglect/abuse |
| • Biological vulnerabilities in nervous system? | • Personality/coping style | • Poor family functioning | |
| • Disease | |||
| Precipitating | • Abnormal physiological event or state (e.g. hyperventilation, sleep deprivation, sleep paralysis) | • Perception of life event as negative, unexpected | • Symptom modelling (via media or personal contact) |
| • Physical injury/pain | • Depression/anxiety | • Life events and difficulties | |
| • Acute dissociative episode/panic attack | |||
| Perpetuating | • Plasticity in CNS motor and sensory (including pain) pathways | • Perception of symptoms as being outwith personal control/due to disease | • Fear/avoidance of work or family responsibilities |
| • Deconditioning (e.g. lack of physical fitness in chronic fatigue, deconditioning of vestibular responsiveness in patients with dizziness who hold their head still) | • Anxiety/catastrophisation about cause of symptoms | • The presence of a welfare system | |
| • Neuroendocrine and immunological abnormalities similar to those seen in depression and anxiety | • Not being believed | • Social benefits of being ill | |
| • Avoidance of symptom provocation (e.g. exercise in fatigue) | • Availability of legal compensation | ||
| • Stigma of “mental illness” in society and from medical profession |