14 DAY TRIAL // Researchers were actually trying to find out if there is a correlation between the decrease of suicide rates and the rise in new antidepressants sales, in the last decades.
The Norwegian Institute of Public Health carried out a new study based on figures from the Nordic countries, and concluded that there not enough evidence to link sales of new drugs to a lower suicide rate.
They gathered data about suicide rates (number of suicides per 100 000 inhabitants) from the Nordic countries, as well as the figures generated by antidepressants sales, SSRIs (selective serotonin reuptake inhibitors) and TCAs (tricyclic anti-depressants), and for the study they considered 60,000 suicide cases.
Scientists developed a statistical analysis of a possible relationship between suicide rates and antidepressants sales from 1990 to 1998 in Norway, Sweden, Denmark and Finland.
In these countries, suicide rates have been declining since the end of the 80's, and around 1990, the SSRI drugs became available.
SSRI sales have been increasing every year, whereas TCA sales declined significantly – TCA drugs presenting a risk of poisoning overdose.
The researchers investigated for a relationship between reduced sales of the older and more toxic antidepressants and a reduction in suicide rates, without finding anything conclusive.
The interesting thing that they discovered was that when they studied the Nordic countries as a group, they found no correlation between suicide rates and antidepressants, old or new.
But a previous study carried out by the NIPH (Bramness et al, 2007), considering only Norway, managed to find a relationship between higher SSRIs sales and a decline in suicide rates at the beginning of the 90's.
The scientists then suggested that this was explained by the fact that less people used TCAs to commit suicide.
Back to this recent study, the researchers' conclusions are that the reduction in TCA sales cannot explain the reduction in suicide rates, and this last is not affected by antidepressants sales.
They added that the valid explanation might be given by other factors, that are, for now, poorly understood and difficult to measure.
This new study was recently published in BMC Psychiatry.