Psychiatric comorbidities cluster early after onset in MOGAD: a cross-sectional comparative study with MS and NMOSD.

BACKGROUND: Psychiatric comorbidities are increasingly recognised in demyelinating diseases, yet their frequency and timing in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) are not well defined. We aimed to characterise the spectrum and temporal pattern of psychiatric illness in MOGAD and compare to multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) with aquaporin-4 antibody (AQP4-IgG). METHODS: We conducted a cross-sectional study of patients with MOGAD (n=388), age-matched and sex-matched MS (n=257) and AQP4-IgG-positive NMOSD (n=58) evaluated at Mayo Clinic (1991-2025). Psychiatric diagnoses, timing relative to the first attack and patient-reported outcomes were extracted from electronic health records (EHRs). Complementary analyses were conducted using the NeuroBlu real-world EHR database. RESULTS: Among 388 patients with MOGAD, 54.8% had ≥1 psychiatric disorder, most commonly anxiety (47.7%), depression (36.6%) and attention-deficit/hyperactivity disorder (ADHD, 9%). After the first attack, 33.3% of patients with MOGAD developed a new psychiatric disorder, often within the first year. MOGAD showed a lower frequency of depression versus MS (36.6% vs 47.5%, p=0.02) but similar rates of anxiety and ADHD. Temporal patterns differed: psychiatric disorders often appeared years before onset in MS but clustered shortly after onset in MOGAD. NeuroBlu analyses supported high rates of psychiatric disorders across the three conditions. CONCLUSION: Psychiatric comorbidities are common in MOGAD, particularly depression and anxiety, typically emerging close after onset, whereas in MS they often preceded onset by years. These findings underscore the need for routine psychiatric screening in MOGAD and highlight unresolved questions regarding whether, and to what extent, MOG-IgG-mediated inflammatory demyelination contributes to psychiatric vulnerability.