Psychosocial correlates of seizure frequency in Functional/Dissociative Seizures (FDS): A systematic review

Seizure frequency is commonly used as a primary outcome and proxy for severity in functional/dissociative seizures (FDS), despite uncertainties about its validity and reliability. This systematic review aimed to describe how FDS frequency has been measured and to identify its correlates.

Following pre-registration, PsycInfo, MEDLINE, CINAHL and Cochrane Reviews were searched using terms relating to FDS, seizure frequency and/or severity, and correlates. Eligible studies reported correlational data between FDS frequency and psychosocial variables in adults. Correlates were organised by conceptual domain and narratively reviewed.

Eighteen studies capturing data from 848 people with FDS were reviewed. There was considerable variation in how FDS frequency was measured, with most studies relying on retrospective self-reported seizure counts over the previous month (or four weeks). While health-related quality of life, distress and general functioning were negatively affected in those with FDS, these were not always correlated with seizure frequency, or observed associations were often weak. Stronger relationships tended to be found between FDS frequency and specific measures of functioning, such as avoidance, self-esteem, coping and hyperventilation. Demographics showed little association with FDS frequency.

While FDS frequency remains clinically relevant, findings support the argument against using seizure counts as the primary marker of severity. Instead, they should be interpreted within a broader assessment of condition severity and patient wellbeing.