BACKGROUND: Suicidal behaviour is related to psychosocial and biological factors. Although suicide is strictly forbidden by the Islamic faith, there are non-confirmed observations of increased suicidality on religious feast days. The objective of the present study was to find out if suicide attempts of youths living in Istanbul increase on religious feast days compared to ordinary and non-religious holidays.

METHODS: We retrospectively analyzed all suicide attempts (N = 2,232) of young people up to 25 years of age seeking support at various hospitals in Istanbul in 2010. The main hypothesis was that the number of suicide attempts would increase during religious feast days.

RESULTS: The number of suicide attempts was higher on religious feast days and non-religious holidays except for New Year's Day and International Labour Day than the daily average number of the actual months. Like on ordinary days, more female than male youth (84.9 % vs. 15.1 %) attempted suicide on feast days.

CONCLUSION: We speculate that changes of the daily rhythm and increased family interaction on feast days and non-religious holidays could lead to unexpected confrontations and disputes instead of the expected positive family climate. This "Broken-Promise Effect" and changes of the daily rhythm could contribute to the observed increased suicidal behaviour.