We 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.