Suicide methods were classified into six categories according to the ICD-10 codes: poisoning (X60–X69), hanging (X70), firearms (X72–74), jumping from a high place (X80), jumping in front of moving objects (X81-X82), and others (X71, X75–X79, X83–X84). The study was approved by the institutional review board (IRB) for human subjects at the Seoul National University College of Medicine.