Hallucinations and related perceptual phenomena in systemic lupus erythematosus and inflammatory arthritis: A cross-sectional mixed-methods study

Background: The INSPIRE (Investigating Neuropsychiatric Symptom Prevalence and Impact in Rheumatology Patient Experiences) research project explored neuropsychiatric symptoms associated with Systemic Autoimmune Rheumatic Diseases (SARDs), identifying hallucinatory experiences as lesser known but impactful symptoms. Following consultations with clinicians and patients, areas of focus included the prevalence, sensory modalities, insight, timings, and emotional valence of hallucinations in SARDs. Our previous research shows that hallucinations and related perceptual phenomena often go unreported and unrecognised in clinical settings with SARD patients. Objective: This study analyses and compares hallucination experiences in patients with systemic lupus erythematosus (SLE) and inflammatory arthritis (IA). We evaluated prevalence, modalities, insight, emotional valence, and timings of hallucinations. Methods: Quantitative data from cross-sectional surveys (n = 1022) and qualitative data from interviews were integrated using mixed methods. Quantitative data are presented descriptively and comparatively (using Pearson's χ ² tests), and qualitative data were analyzed thematically. Results: SLE patients reported a greater lifetime prevalence of hallucinations than IA patients, with significant differences in visual (12% vs 6%), olfactory (11% vs 6%), tactile (11% vs 5%), and presence (10% vs 3%) modalities (all P < 0.005). Auditory hallucinations were not significantly more frequent in SLE (8%) than IA (5%) (P = 0.071). Consistent lack of insight into hallucinations was rare (11% of SLE and 4% of IA patients). SLE patients were significantly more likely to experience hallucinations in contexts unrelated to periods of sleep transition than IA patients (P = 0.020). Recognizing hallucinations as SARD symptoms helped patients develop positive coping mechanisms and reduced distress. However, fear of clinician judgment, stigma, and misdiagnoses discouraged reporting. Conclusions: The higher prevalence in SLE likely reflects its greater direct impact of SLE (compared to IA) on the brain. Hallucinatory experiences in SARDs aligned more closely with neurological diseases than primary psychotic disorders. Understanding the varying modalities and contexts of hallucinations as potential direct effects of SLE could improve attribution, treatment, and coping strategies, while reducing stigma and fostering open communication between patients and clinicians.