Objective  

To identify cause-of-death categories in which suicides might be misclassified in Taiwan.

Methods  

We plotted secular trends (1971–2007) in sex- and method-specific rates of deaths classified as suicide, undetermined intent and accident for the Taiwanese population aged 15+ and compared the sex, age and marital status profiles of deaths in these three categories by method of death.

Results  

The demographic profiles of registered suicides generally resembled those for deaths of undetermined intent and accidents by pesticide poisoning/suffocation but differed from those for accidents from non-pesticide poisoning/drowning/falling/poisoning by non-domestic gas. For the period 1990–2007, suicide rates based on suicides alone (14.8 per 100,000) would increase by 23, 7 and 1%, respectively, when including deaths of undetermined intent, accidental pesticide poisonings and accidental suffocations.

Conclusions  

Suicide rates may be underestimated by more than 30% in Taiwan because some suicides are ‘hidden’ amongst deaths certified as due to other causes.