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Correspondence |
National Institute for Psychiatry and Neurology, Budapest, Hungary
Department of Psychiatry and Psychotherapy, Semmelweis Medical University, Budapest, Hungary
Department of Psychiatry, Neurotec, Karolinska Institute, Karolinska University Hospital Huddinge, S-141 86 Stockholm, Sweden.
Correspondence: E-mail: Goran.Isacsson{at}neurotec.ki.se
Helgason et al (2004) reported that the dramatic increase in the sales of antidepressants in Iceland had not had any impact on suicide rates. While the sales of antidepressants increased fivefold from 14.9 defined daily doses per 1000 persons per day in 1989 to 72.7 in 2000, the suicide rate remained quite stable (around 11/1000 000 persons per year). The data were, however, not analysed separately by gender.
Based on the World Health Organization database on national suicide rates, Levi et al (2003) compared the periods 1980–84 and 1995–99, and found that suicide rates in Iceland decreased by 1.7% in males during the whole period (17.9 to 17.6) and by 46.7% in females (from 6.0 to 3.2). In spite of the fact that the time periods investigated by Helgason et al (2004) and Levi et al (2003) are not exactly identical, the general trends should be similar. Given this extremely great (27-fold) difference in the decrease in suicide rates between males and females, it would be interesting to see the data on the use of antidepressants in Iceland between 1989 and 2000 for males and females separately. Perhaps the increase in the use of antidepressants was more pronounced in women than in men, as for example in Australia (Hall et al, 2003)?
A significant negative correlation between antidepressant prescription and national suicide rates has been reported from Sweden, Denmark, Finland and Norway (Isacsson, 2000) as well as from Hungary (Rihmer, 2004), countries where suicide rates have been traditionally high. Statistical association, of course, does not necessarily imply causality, but considering the strong relationship between untreated depression and suicide, the national trends mentioned above point in the expected direction. On the other hand, however, if a marked increase in antidepressant utilisation is not accompanied by a substantial decline in the suicide rate, it does not mean that better and more widespread treatment of depression is not helpful for preventing many suicides. While the overall suicide rate of Australia and Northern Ireland (two countries with traditionally low suicide rates) have not substantially decreased during the past 10 years, a significant association between increased antidepressant use and decreased suicide rates in different age cohorts has been reported (Hall et al, 2003; Kelly et al, 2003).
REFERENCES
Hall, W. D., Mant, A., Mitchell, P. B., et al
(2003) Association between antidepressant prescribing and
suicide in Australia, 1991–2000: trend analysis.
BMJ, 326, 1008
–1012.
Helgason, T., Tómasson, H. & Zoëga, T.
(2004) Antidepressants and public health in Iceland: time
series analysis of national data. British Journal of
Psychiatry, 184, 157
–162.
Isacsson, G. (2000) Suicide prevention – a medical breakthrough? Acta Psychiatrica Scandinavica, 102, 113 –117.[CrossRef][Medline]
Kelly, C. B., Ansari, T., Rafferty, T., et al (2003) Antidepressant prescribing and suicide rate in Northern Ireland. European Psychiatry, 18, 325 –328.
Levi, F., La Vecchia, C., Lucchini, F., et al (2003) Trends in mortality from suicide, 1965–99. Acta Psychiatrica Scandinavica, 108, 341 –349.[CrossRef][Medline]
Rihmer, Z. (2004) Decreasing national suicide rates — fact or fiction? World Journal of Biological Psychiatry, 5, 55 –56.
Faculty of Economics and Business Administration, University of Iceland
Faculty of Medicine, University of Iceland; correspondence: 4 Midleiti, IS-103 Reykjavik, Iceland.
National University Hospital, Reykjavik, Iceland
Correspondence: E-mail: tomashe{at}isholf.is
We have data on the suicide rates by gender from 1978 to 2000. The average rate for that period is about 19 per 100 000 for men and about 5 for women. The yearly data series for women is a sequence of numbers varying from 3 to 14. Because of the small number of female suicides they can vary considerably. Even 5-year averages would have large standard deviations. If an over-dispersion coefficient of 2 is assumed, the size of the standard deviation in 5-year averages should be around 1.4 for women and 2.6 for men. Therefore, observed 5-year averages of 4–7 for women and 17–22 for men could be expected. Average rates may vary according to choice of 5-year periods (Fig. 1). The rates during 1995–1999 were 18.1 for men and 4.6 for women, but 21 for men and 5 for women during 1996–2000. The rates quoted in Isacsson’s letter for 1995–1999 are actually for 1995–1996 (Levi et al, 2003) and too low. Taking 5-year averages is a waste of information because it ignores the time series structure in the data. With such limited data as the number of suicides in Iceland it is vital to use statistical techniques that use data as efficiently as possible. In this case the dynamics of suicide rates seemed to be similar for both genders, so data on them was pooled. In our opinion time series methods should be used for these data as they take advantage of the time series structure of the data. Furthermore, a time series approach leads to improved P values and decreases the possibility of spurious regression (Granger & Newbold, 1974).
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In our paper (Helgason et al, 2004a) we mentioned that suicide rates had not decreased in Norway since 1995 in spite of increasing antidepressant sales.
In 1989 the amount of antidepressants prescribed was 13.9 defined daily
doses per 1000 per day for men and 27.6 for women aged 
15 years
(Helgason et al,
1997). The amount prescribed in 2001 had increased to 66.8 and
119.1 defined daily doses per 1000 per day for men and women, respectively
(Helgason et al,
2004b), i.e. a slightly greater increase for men without
affecting suicide rates for either gender.
REFERENCES
Granger, C. W. J. & Newbold, P. (1974) Spurious regression in econometrics. Journal of Econometrics, 2, 111 –120.[CrossRef]
Helgason, T., Björnsson, J. K., Zoëga, T., et al (1997) Psychopharmacoepidemiology in Iceland: effects of regulations and new medications. European Archives of Psychiatry and Clinical Neurosciences, 247, 93 –99.[Medline]
Helgason, T., Tómasson, K. & Zoëga, T.
(2004a) Antidepressants and public health in
Iceland: time series analysis of national data. British Journal of
Psychiatry, 184, 157
–162.
Helgason, T., Tómasson, K., Sigfússon, E., et al (2004b) Screening for mental disorders in the community 1984 and 2002 and prescriptions for psychopharmaca in 1984 and 2001. Læknablaðið (Icelandic Medical Journal), 90, 553 –559.
Levi, F., La Vecchia, C., Lucchini, F., et al (2003) Trends in mortality from suicide, 1965–99. Acta Psychiatrica Scandinavica, 108, 341 –349.[CrossRef][Medline]
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| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
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