Subjective symptoms of functional/dissociative seizures and their diagnostic value: A systematic review

OBJECTIVE: Although subjective symptoms have received less attention than observable manifestations of functional/dissociative seizures (FDS), patient-reported experiences provide important insights for diagnosis and management. This systematic review summarizes and synthesizes studies describing the subjective symptomatology of FDS and narratively discusses their potential diagnostic value. METHODS: MEDLINE, PsycINFO, and CINAHL were searched from January 1990 to May 2025 for studies reporting qualitative or quantitative data on FDS symptoms. The review was registered in International Prospective Register of Systematic Reviews (PROSPERO; CRD420251008332) and reported in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines. Study quality was assessed using Critical Appraisal Skills Programme (CASP) tools. Data were extracted on study design, sample characteristics, data acquisition method, and reported symptoms. Qualitative data were analyzed thematically following Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ) principles, whereas quantitative findings were synthesized narratively within the same thematic framework. RESULTS: Forty-seven studies were included. Subjective symptoms of FDS were highly variable both within and between individuals. Across studies, six broad symptom domains were identified: sensory/pain, arousal, emotional, consciousness-related, cognitive, and motor symptoms. Sensory symptoms (particularly pain and headache), arousal-related symptoms (especially hyperarousal), and emotional symptoms (especially panic and anxiety) were most frequently reported across studies. Symptoms related to altered awareness and dissociation between awareness and responsiveness were described in a smaller number of studies but were more consistently reported as differentiating FDS from epileptic seizures. In contrast, the differential diagnostic value of other subjective symptoms was limited by lack of specificity and insufficient detail regarding context, mode of onset, spread, duration and quality. SIGNIFICANCE: Subjective symptoms in FDS are diverse, but common themes emerge. Detailed descriptions are required to extract differential diagnostic value from subjective FDS symptoms. Future studies should collect structured information about FDS symptoms and study them using systematic, multimodal, and cross-cultural approaches.