A Biblical Perspective on Mental Illness and Suicide

What is the relationship between mental illness and suicide? Is that the best way to ask my question? If not, how would you frame the problem of a person who commits suicide? What does the Bible say? I deal with many desperate people who are Christian and non-Christian, and the normalization of suicide over the past few years has created not just an interest in self-harm but an acceptable solution to commit suicide. What are your thoughts?