Decrease in Suicide Not Linked to Newer Antidepressants, Norwegian Study Finds

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Not Linked to Newer Antidepressants, Norwegian Study Finds

ScienceDaily (Sep. 29, 2010) — Many researchers have studied the relationship

between the increase in sales of new antidepressants in recent decades and a

simultaneous decline in the suicide rate. In a study based on figures from the

Nordic countries, researchers at the Norwegian Institute of Public Health found

no evidence that increased sales of the new medicines could be linked to a lower

suicide rate. The researchers also did not find any relationship between reduced

sales of the older and more toxic antidepressants and a reduction in suicide

rates.

The suicide rate has been declining since the end of the 1980s in many Western

countries, including Norway, Sweden, Denmark and Finland. Around 1990, the new

SSRI drugs (selective serotonin reuptake inhibitors) became available on the

market. Sales figures for these new antidepressant drugs have increased

annually, whereas sales of the older TCA drugs (tricyclic anti-depressants) have

declined substantially. TCA drugs are associated with a risk of poisoning with

overdose.

In a study recently published in BMC Psychiatry, the researchers gathered data

from the Nordic countries about the suicide rate (number of suicides per 100 000

inhabitants) and sales figures for antidepressants, both for SSRIs and TCAs. A

total of over 60 000 suicides were included in the study. Scientists have

performed a statistical analysis of the relationship between changes in suicide

rates and changes in sales figures for both new and older antidepressants in the

period 1990-98 in the respective countries. It is during this time period that

the increase in sales was greatest and where the greatest drop in suicide rate

could be expected.

The main questions asked were:

•Can a significant increase in sales of SSRIs in any one year be related to a

sharp decline in the suicide rate in the same year?

•Can the decline in sales of TCAs be related to the decrease in the suicide

rate?

When the Nordic countries are studied as one group, the study concludes with a

negative answer to both questions.

In a previous study by the NIPH (Bramness et al, 2007) a correlation between the

increase in sales figures for SSRIs and the decrease in suicide rate in Norway

at the beginning of the 1990s was observed and it was suggested that this could

be explained by the fact that fewer people used TCAs to commit suicide. In the

new Nordic study this correlation can be disregarded when the other countries

are included in the analysis. The new study also found that the reduction in TCA

sales cannot explain the reduction in suicide rates. The researchers behind the

study conclude that the suicide rate is not affected by sales of

antidepressants, but by other factors that are little understood and are

difficult to measure.

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Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff)

from materials provided by Norwegian Institute of Public Health.

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Journal Reference:

1.Zahl PH et al. The relationship between sales of SSRI, TCA and suicide rates

in the Nordic countries. BMC Psychiatry, 2010; 10: 62