In Finland the majority of the users of antidepressants are women and old age people. In the 80's the number of fatal poisonings has increased. During the years 1985-1987 58% of these poisonings were women who belonged to the younger age group of the users. The older tricyclic drugs are known to be more toxic, at least in overdose, than the newer antidepressants especially when they are compared to mianserin. Of the latter, however, lately more serious side effects have been reported. For this reason the use of the different kinds of antidepressants in Finland had changed: the sales of doxepin and amitriptyline have increased and those of maprotiline and mianserin have decreased. To study the role of antidepressants in sudden and unexpected deaths the fatality ratio (defined as fatalities divided by defined daily doses per 1000 inhabitants/day) was calculated for four most prescribed antidepressants. As to the sales, amitriptyline has to be considered to be the leading antidepressant followed by doxepin, mianserin and maprotiline. As a detection in the forensic toxicological screening the sales related ratios showed that maprotiline was most commonly found followed by doxepin, amitriptyline and mianserin. When an antidepressant was the cause of death the fatality ratio was highest for doxepin (6.4) followed by maprotiline (4.3), amitriptyline (4.0) and mianserin (1). In cases of established suicides the order was the same again.(ABSTRACT TRUNCATED AT 250 WORDS)