Drop attacks as a subtype of FND: A cognitive behavioural model using grounded theory.

Idiopathic drop attacks are falls to the floor, without warning, and without loss of consciousness, for which the cause is uncertain. They are poorly studied but recent research suggests that many idiopathic drop attacks may be usefully considered within the spectrum of functional neurological disorder (FND). The aim of this study was to test a cognitive behavioural model of idiopathic drop attacks, in order to inform formulation and treatment. Interviews and diaries were completed by seven individuals experiencing drop attacks, and were analysed using a grounded theory qualitative data approach. Through the coding and synthesis of data into themes, a proposed cognitive behavioural model was identified, with a main precipitating event in all cases being a fall related to another cause, such as a mechanical fall or a fall due to medical reasons. Additional precipitating factors identified included situational triggers, high levels of stress, and dissociation. A maintaining cycle of thoughts, emotion and behaviour is outlined. Our proposed theory is consistent with current cognitive behavioural models of FND. A cognitive behavioural understanding of drop attacks when considered part of FND aids formulation in clinical practice, and suggests that cognitive behavioural therapy interventions for FND may also be applicable in this population.