OBJECTIVES: Estimate the cost of a psychiatric relapse in the Brazilian private healthcare system. METHODS: Using a claims database, 842 patients were classified according to one of the following diagnoses: organic delusional disorder (schizophrenia-like), schizophrenia, schizotypal disorder, persistent delusional disorder or schizoaffective disorder. During 26 months, from August/2009 to September/2011, all patients that first used the private healthcare system were analyzed and followed. All costs associated with the treatment of schizophrenia were considered across seven major categories: hospitalization, medications, procedures, materials, exams, alimentation and hygiene care. RESULTS: Out of the 842 patients that used the private health care system in a period of 26 months, 388 returned to the hospital (“return patients”, 46%) and accounted for 85% (R$ 8,800,518.79) of the costs during the period of the analysis. The majority of the “return patients”, 57% (n=221), were re-hospitalized between 2 and 4 times, and 9% (n=35) returned 20 times or more during the period studied. “Return patients” presented an average total cost of R$ 22,681.75/patient in 26 months, a cost per patient more than 6 times higher when compared with those that did not return (R$ 3,511.72/patient/26 months). Most costs were accountable to hospitalization (75%), followed by medication (14%).  The most frequently used medications by the 842 patients, in units, in decreasing order were: levomepromazine, haloperidol and clonazepam. CONCLUSIONS: Although patients with hospitalizations represented 46% of the sample, they accounted for 85% of the costs occurred in the 2 year period. As a result, avoiding hospitalization in psychiatric relapse could be an effective cost-saving investment. Furthermore, the claims database does not consider all outpatient costs incurred by the sample, so these results might be underestimated.