Citation trends of general psychiatric journals.

Journals play a vital role in the communication of medical knowledge but little is known about their relative influence and how this may change over time. Citation analysis is one method which allows an objective assessment of scientific research. It has been used as a measure of research achievement by which national and individual academic performance can be judged (Smith et al. 1986; Evered et al. 1987) and it can be applied to journals as well as to individual authors (Garfield, 1972). When a journal article is cited in a subsequent publication it indicates that it has influenced the subsequent work. Thus, it follows that journals which are cited most frequently are likely to be those which are most influential within their particular field (Garfield, 1986). This measure of influence must be distinguished from those obtained by quantifying readership or circulation. Many medical publications have large circulations because they are distributed unrequested and free of charge. Others are official publications of professional organizations and are circulated to all members of those organizations who have paid their membership fees. Citation analysis has been traced back for at least 70 years (Lock, 1985) but in modern context it dates from 1964 with the publication of the Science Citation Index by the Institute for Scientific Information in Philadelphia (Garfield, 1970). Each year since 1975 this has been supplemented by the Journal Citation Reports which now cover several million references published in over 12000 journals. Source item counts include original articles, technical notes, reviews and papers presented as proceedings which have been published in the journals surveyed. They do not include editorials or letters unless these report the results of substantive research. The Journal Citation Reports rank journals each year according to the total number of citations made to the journal in that year. There are separate listings for the number of citations made to each journal for articles published during the previous two years. The Journal Citation Reports also calculate an impact factor which takes into consideration the possibility that a particular journal may be cited frequently merely because it publishes a large number of articles. The impact factor for a given year is calculated by listing all citations during that year to articles published during the previous two years divided by the total number of articles published during those two years. This reflects the average citation rate of each published article and reduces the effect of a journal's size, age and frequency of publication. Garfield (1972) has shown that there is a predominance of a small group of journals in the citation network in that the majority of references cite relatively few journals. He has suggested that there is a multidisciplinary core for all sciences comprising no more than 1000 journals. Using data from the 1981 Journal Citation Reports for general medical journals it has been shown that the Lancet and the New England Journal of Medicine have the greatest influence as judged by the number of citations received and their impact factor (Garfield, 1986). Indeed, these two journals between them received over one third of all 1981 citations. What is the position of general psychiatric journals? During the decade ending in 1986, the last year for which figures are available, five journals which cover the whole range of psychiatric specialities were consistently ranked in the top 1000 scientific publications according to the total citations received in each year. These were Acta Psychiatrica Scandinavica, American Journal of Psychiatry, Archives of General Psychiatry, British Journal of Psychiatry and Journal of Nervous and Mental Disease. Psychological Medicine, a more recently established journal first published in 1970 was ranked in the top 1000 for each of the last eight years of the decade. The total citations received by each journal are shown in Fig. 1. Two American journals, the Archives of General Psychiatry and the American Journal of Psychiatry are clearly the most