Validity of a Brazilian version of the Zung self-rating depression scale for screening of depression in patients with Parkinson's disease.
BACKGROUND
Parkinson's disease (PD) is a neurodegenerative disorder with prominent motor manifestations and many other non-motor symptoms that significantly decrease quality-of-life and are frequently under-recognized, for example depression.


OBJECTIVE
To study the validity of a Brazilian version of the Zung Self-rating Depression Scale (SDS) for the diagnosis of depression in patients with PD.


METHODS
We evaluated 78 consecutive non demented patients over the age of 40 with diagnosis of PD at a Movement Disorders Outpatient Clinic, who could read and understand questionnaires. They completed the SDS and the Geriatric Depression Scale with 15 items (GDS-15). The diagnosis of depression was made after a structured clinical interview based on DSM-IV criteria for the diagnosis of major depression (SCID-CV).


RESULTS
The prevalence of major depression was 23.1%. Cronbach's alpha was 0.73 and the area under the ROC curve was 0.93 for the SDS. The score index of 55 had a sensitivity of 88.9% and a specificity of 83.3% for the diagnosis of depression. The total scores of the SDS and GDS-15 were highly correlated (0.652, p < 0.0001) and correlated weakly with the scores of a motor scale.


CONCLUSIONS
The SDS is a valid tool for screening depression in patients with PD since the specific SDS index of 55 is adopted. Two shortened versions could be used with good results.
Chagas
Marcos Hortes Nisihara
MH
Behavioral Neurosciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Sao Paulo, Brazil.
Tumas
Vitor
V
Loureiro
Sonia Regina
SR
Hallak
Jaime E C
JE
Trzesniak
Clarissa
C
de Sousa
João Paulo Machado
JP
Rodrigues
Guilherme Gustavo Ricciopo
GG
Santos Filho
Alaor
A
Crippa
José Alexandre S
JA
D000368:Aged; D001938:Brazil; D003863:Depression / Q000150:complications / Q000175:diagnosis / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D011569:Psychiatric Status Rating Scales; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012649:Self Concept; D014175:Translating