Global research trends and publications of insomnia : A bibliometric analysis

This study aimed to evaluate the tendency of insomnia articles in SCI-EXPANDED database. Data was obtained from the online version of Science Citation Index Expanded (SCI-EXPANDED) database in the Web of Science Core Collection of Clarivate Analytics within the publication year from 1991 to 2018. The publications were assessed regarding their document types, languages, and journals. We used three citation indicators such as C-2018, TC2018, and CPP2018, to determine the citation received by publications. We used the Y-index method formulated by Ho. The study found 16,478 insomnia documents within 15 document types indexed in the Web of Science, and articles type was used most constituting 66% (10,801) of the documents. Ninety-five percent of the articles were published in English. The journal of Sleep published most of the insomnia article then followed by Sleep Medicine. The 30% of 10,801 articles were published in the top category of clinical neurology. The G7 countries published most of the insomnia articles. The most productive country and institution was United States and Harvard University respectively. The article entitled "A new method for measuring daytime sleepiness: The Epworth sleepiness scale" published by johns in 1991 was the most cited article with TC2018 of 7,191 and C-2018 of 661 citations. The most industrious and had more potential to published insomnia articles was M.M. Ohayon. Moreover, the study showed that most of the insomnia articles were related to depression, anxiety, cancer, and schizophrenia. Insomnia is a serious problem with synergistic effects for normal body health. Bibliometric method can help researchers to have comprehensive knowledge on insomnia and initiate an orientation for further research so as to solve a problem. Furthermore, it may also help researchers to determine the impact of insomnia publications as well as to identify relevant research groups in the field of insomnia.