Prevalence and underrecognition of dysthymia among psychiatric outpatients in Sمo Paulo, Brazil

Background: Dysthymia is a highly prevalent disorder with rates varying from 3 to 6%. It is estimated that 7% of primary care and up to 36% of the psychiatric outpatients have this disorder. Dysthymia is characterized by a pattern of low intensity and long duration depression, leading to impairment in many aspects of the patient’s life (work, family). However, it is a condition which is not frequently diagnosed, thereby remaining untreated and leading to chronification, risk of developing depression and substance abuse. Despite the well-known fact that dysthymia is underdiagnosed, there are no studies in Brazil regarding this problem. This paper presents a study on the prevalence of dysthymia in an outpatient psychiatric population in São Paulo, Brazil, identifying factors associated with the underdiagnosis of dysthymia. Methods: Two raters carried out a study of 81 patients from a university outpatient clinic in São Paulo, using the SCID-I/P. The κ coefficient was used to measure the inter-rater reliability for the dysthymia diagnosis. The SCID-I/P diagnosis was compared to consulting psychiatrist’s diagnosis. Factors associated with underdiagnosis were identified. Results and conclusions: 27% of the sample had SCID dysthymia. They presented more comorbidities than non-dysthymics. Only 27% of these SCID dysthymics were considered ‘pure’ dysthymics. Clinicians had identified only 37% of these SCID diagnosed cases as dysthymic. The main reason for missing diagnosis of dysthymia in this sample was axis I comorbidity. Limitation: As we did not investigate the presence of personality disorder, the impact of axis II on misdiagnosis of dysthymia could not be investigated in our sample.