I'm not too familiar with studies on suicide, but since this is posted in God thread, I think I can find some relation.
From the scripture, there are two big figures who committed suicide - King Saul and Judas Iscariot.
King Saul took a sword and fell dead before Philistines (Israel's enemy at the time) would come and kill/torture him. Judas Iscariot hung himself after feeling guilty about betraying Jesus. Although he hung himself, he actually died by falling to the ground/field/rock as described in Acts 1.
I believe both committed suicide because of their self guilt, but in the end it was really the faithlessness that led them so. Some say Saul died as a hero since he refused to be killed by the enemy, but if he truly had faith in God, he should have repented and surrendered by believing God would rescue. Same thing with Judas. The only difference between Judas and Peter is that Peter didn't kill himself for betraying Jesus. He was restored to be a stronger person by the resurrected Christ Himself and Judas missed that because he already ended his life by himself.
We're all like Saul and Judas. We might see them as villains, but we are much like them having lack of faith time to time even though we might call ourselves Christians. Suicide is a horrible act most might not dare to even think of committing, but faithless living is like a hopeless life that's no different than a life ended in suicide. Ever since Adam brought sin into this world, this world is full of corruption even if it might look like it's getting better (it's actually getting worse). The only way to survive is to keep asking Jesus Christ constantly to forgive and deliver us from our sinful natures, suicide being one of them. The Holy Spirit then will guide us to live faithful as promised by Jesus Himself.
May God give true hope and peace, Jesus Himself, to the family of the one who committed suicide in S. Korea.