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Archived Comments for: The relationship between sales of SSRI, TCA and suicide rates in the Nordic countries

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  1. Sales of SSRI and suicide rates

    Aage Tverdal, Norwegian Institute of Public Health

    15 October 2010

    Zahl and collegues have done an ecologic study and found no evidence of any inverse relationship between the increase in sales of SSRIs and the declining suicide rates in four Nordic countries.
    Data were analysed by Fisher's exact test and Pearson's correlation coefficient, according to the abstract.
    I suspect that country has not been taken into account in the analyses. Table 1 gives the data on which the analyses are made. The overall Pearson correlation coeffcient between annual changes in suicide rates and annual changes in sales figures of SSRIs is 0.06 (p=0.76). Country specific correlations are -0.54 (p=0.17), 0.78 (p=0.02), 0.25 (p=0.55) and -0.98 (p=0.02) for Norway, Sweden, Finland and Denmark, respectively. Heterogeneity between the countries is more prominent than a homogenous null effect.

    Competing interests

    I declare no conflict of interest

  2. Reply to Aage Tverdal: Sales of SSRI and suicide rates

    Per-Henrik Zahl, Norwegian Institute of Public Health

    23 December 2010

    Tverdal et al. [1] have previously published that there was a negative association between increasing sales of selective serotonin re-uptake inhibitors (SSRIs) and declining suicides rates in the early 1990’s in Norway. He suggested that the rapid swift from using SSRI to using tricyclic antidepressiva (which are potentially more toxic than SSRI) could explain why suicide rates fell early in the 1990 but not later. We published that if we aggregate all Nordic countries, there is no statistical association [2].

    Tverdal writes that “Heterogeneity between the countries is more prominent than a null effect”. First, we did not say there was no effect in all countries. We argued that the association varied between countries and that the average effect was null, and therefore his paper [1] is a typical example of publication bias. Second, his statement may be interpreted as criticism of our use of pooled data. However, pooling of data is the fundamental principle of meta-analyses and review papers.

    1. Bramness J, Walby FA, Tverdal A: The sales of antidepressants and suicide rates in Norway and its counties 1980 - 2004. J Affect Disorders 2007, 102:1-9.

    2. Zahl P-H, De Leo D, Ekeberg Ø, Hjelmeland H, Dieserud G. The relationship between antidepressants (TCAs and SSRIs) and the suicide rates in four Nordic countries. BMC Psychiatry 2010; 10: 62. doi:10.1186/1471-244X-10-62

    Competing interests

    We declare no conflict of interest

  3. The relationship between sales of SSRI with Suisidal Rate

    kithsiri senanayake, Rajarata University of Sri Lanka

    12 January 2011

    The suicidal rate in Sri Lanka had been very high, and it was the highest rate in the world. However the incidence is drastically declined past few years and the reason for this decline is multifactorial. There are no data as to say whether the sales of SSRI increased in Sri Lanka but apparently the use of SSRI is increased among the population. It is very difficult to correlates the suicidal risk to the SSRI sales in general population because of following reasons.

    1. SSRI became popular due to its low side effects profile

    2. SSRI are used not only as an antidepressant but also as anxiolitic, for the personality disorders, and as a treatment for insomnia etc.

    3. The magnitude of benefit of antidepressant medication compared with placebo increases with severity of depression symptoms and may be minimal or nonexistent, on average, in patients with mild or moderate symptoms. For patients with very severe depression, the benefit of medications over placebo is is substantial(1).

    Therefore the study should be done to assess the effectiveness of the SSRI on preventing the suicidal attempts/incidence, by a randomised controlled trail or an appropriate study protocol rather than thinking interms of sales amount. It is inevitable that the conclusion come as no association between sales of SSRI and suicidal rate in this kind of study.

    1. Fournier JC, et al. Antidepressant Drug Effects and Depression Severity; A Patient-Level Meta-analysis. JAMA. 2010;303(1):47-53.

    Competing interests

    Author declares that there are no competing interests.