Shared Individual Formulation Therapy (SIFT): an open-label trial of a new therapy accommodating patient heterogeneity in functional neurological disorder.

BACKGROUND: Functional Neurological Disorder (FND) is a complex neuropsychiatric condition with a multifactorial aetiology. The heterogeneity of patients with FND is rarely considered in psychotherapy trials, which may contribute to variable outcomes. Shared Individual Formulation Therapy (SIFT) is a new, brief (four session) psychotherapy that aims to accommodate heterogeneity by providing a personalised, trans-theoretical formulation of the person's difficulties and accompanying management plan. METHODS: An open-label, prospective trial of outpatient SIFT for adults with FND was conducted, using health-related quality of life (SF-12) as the principal outcome measure, with secondary measures of mental health, dissociation, health care use and attitude to the FND diagnosis. Measures were collected at baseline, end of treatment and 6- and 12-month follow-ups. RESULTS: Twenty-nine participants with various FND symptoms enrolled. Twenty-four completed all four sessions and 25 completed follow-up measures at 12 months. SF-12 scores improved significantly at end of treatment and were sustained throughout follow-up with moderate effect sizes (0.39-0.47; all p < 0.001). Most secondary outcomes also improved significantly at all time points. The intervention was highly acceptable and tolerable to patients and perceived as beneficial. CONCLUSION: This trial provides preliminary evidence for initial and sustained benefit from SIFT for adults with FND. Further study is needed to validate these findings.