Citation

Ferreira LM, de Lima KP, de Morais AR, Safadi T, Ferreira JL. J. Bras. Psiquiatr. 2021; 70(3): 193-202.

Copyright

(Copyright © 2021, Instituto De Psiquiatria)

DOI

10.1590/0047-2085000000341

PMID

unavailable

Abstract

OBJECTIVE: The aim of this study was to use a wavelet technique to determine whether the number of suicides is similar between developed and emerging countries.

METHODS: Annual data were obtained from World Health Organization (WHO) reports from 1986 to 2015. Discrete nondecimated wavelet transform was used for the analysis, and the Daubechies wavelet function was applied with five-level decomposition. Regarding clustering, energy (variance) was used to analyze the clusters and visualize the clustering process. We constructed a dendrogram using the Mahalanobis distance. The number of groups was set using a specific function in the R program.

RESULTS: The cluster analysis verified the for-mation of four groups as follows: Japan, the United States and Brazil were distinct and isolated groups, and other countries (Austria, Belgium, Chile, Israel, Mexico, Italy and the Netherlands) constituted a sin-gle group.

CONCLUSION: The methods utilized in this paper enabled a detailed verification of countries with similar behaviors despite very distinct socioeconomic, geographic and climate characteristics. © 2021, Editora Cientifica Nacional Ltda. All rights reserved.

Language: en

Keywords

adolescent; adult; human; Brazil; Chile; Mexico; suicide; Japan; female; Austria; World Health Organization; Israel; Mental disorders; Italy; Netherlands; health care policy; algorithm; electroencephalogram; Belgium; cluster analysis; Clusters; decomposition; Article; climate; phylogenetic tree; wavelet transform; Wavelet transform