SummaryWe conducted a prospective cohort study, examining long-term adherence with psychiatric treatment among patients with psychogenic nonepileptic seizures (PNES).Subjects diagnosed with documented PNES were scheduled for 4 psychiatric visits. Survival analysis was performed, and covariates were assessed for association with time to nonadherence using Cox proportional hazard regression analysis. One hundred twenty-three subjects were recruited and followed for up to 17 months. Eighty percent of subjects attended the first outpatient visit, 42% attended the second, 24% attended the third, and only 14% remained adherent through the fourth visit. Two covariates were associated with nonadherence: (1) a prior diagnosis of PNES (hazard ratio 1.57, P-value .046); (2) a lower score on the Brief Illness Perception Questionnaire (BIPQ), signifying lower concern about one's illness (hazard ratio 0.77 for every 10-point increment on the 80-point scale, P-value .008). Adherence with psychiatric treatment among patients with PNES is initially reasonably good but worsens rapidly over visits 2-4. Risk factors for nonadherence include a history of a prior diagnosis of PNES, and a lower level of concern about the illness as assessed by a lower score on the BIPQ. and ratings of disability in PNES are as severe as those in epilepsy.5 Patients with PNES experience long-term economic and social dependence, have frequent emergency department visits and hospital admissions, and incur high medical care costs. [6][7][8] The prognosis for the untreated illness is poor, with 71% of patients having ongoing psychogenic seizures and 56% of patients on disability at 1-to 10-year follow-up. Psychotherapy has been shown to reduce psychogenic seizure frequency and improve quality of life. The strongest evidence basis, including two randomized trials, demonstrates the efficacy of cognitive behavioral therapy.9,10 Yet 20%-30%of patients fail to attend their first appointment after the diagnosis of PNES, and small studies and clinical experience suggest that adherence may significantly deteriorate over longer periods. [11][12][13] Long-term adherence with behavioral health treatments of PNES has received limited attention, and longterm dropout rates are unknown. We therefore conducted a prospective cohort study, measuring adherence with psychiatric follow-up for up to 17 months after diagnosis of PNES.