Functional Neurological Symptom Disorder (Conversion Disorder) from an Interactional Approach: A Composite Case Study

Functional neurological symptom disorder, alternatively termed conversion disorder (FNSD-CD) (Although the DSM-5 utilises the term 'conversion disorder', practitioners and consumers consider this to be an outdated, unsubstantiated and often stigmatising term. In accordance with this, the current terminology used in the field is 'functional neurological symptom disorder'), involves symptoms of altered voluntary motor or sensory functions without identifiable nervous system disease or pathology. It is considered a psychiatric disorder and is, thus, listed in the Diagnostic and Statistical Manual of Mental Disorders (5th Ed.; DSM-5). As per the nosology of the DSM-5, the discrete behavioural or psychological syndrome or pattern observed in FNSD-CD is assumed to be a function of a problem of, or a disorder within, the individual. Accordingly, the psychiatric approach to FNSD-CD, as set out in the DSM-5, invokes an assumption common to the medical model which is that of lineal (i.e., straight-line) causality, namely, causal events are arranged in a lineal sequence. The interactional approach, however, which is a development of general system theory in the field of family therapy, offers an alternative approach to understanding psychiatric disorders. Specifically, this approach places the emphasis on the relationships between individuals and their reciprocal influences on – including their psychological and emotional wellbeing with – one another. It draws on the assumption of nonlineal (i.e., circular) causality, namely, causal events are arranged in a circular sequence. From an interactional approach, therefore, FNSD-CD is thought to be a function of a problem of, or a deficit within, the individuals’ relationship/s, rather than within an individual, per se. This article utilises a composite case study to investigate FNSD-CD from an interactional approach.