Variation in suicide occurrence by day and during major American holidays

Abstract

Background: Due to temporal variations in completed suicides, it has been suggested that impulsivity and environmental factors may influence suicide.

Study objective: Our intent was to determine if particular days of the week, seasons, or holidays were associated with increased attempted and completed suicides by poisoning.

Methods: All calls recorded in the National Poison Database System coded as "suspected suicide" from 2006 through 2010 were included. Exposures were evaluated by day, season, and holidays, and compared to control dates.

Results: There were 1,065,067 exposures (63% female) related to suicide attempts, with completions in 0.4% of cases. Sundays and Mondays for adults, and Mondays and Tuesdays for age < 19 years were the most common. Spring and fall had higher numbers of exposures than summer and winter. New Year's Day had a higher number of exposures, whereas Independence Day, Thanksgiving, and Christmas had fewer exposures.

Conclusions: The beginning of the week, spring and fall, and New Year's Day were associated with higher numbers of ingestions with suicidal intent. This has implications for clinicians advising potential victims and providing emergency care for these patients.

Keywords: holidays; overdose; prevention; seasonal variation; suicide.