Suicide is the deliberate act of taking one’s life immediately. (I’m sure you know this already.) Suicide can be caused by untreated mental problems and issues. One mental issue that causes most suicide is Depression. The sins you listed, such as gluttony, smoking and drug abuse, are much easier to treat than Depression. I’m not saying Depression is incurable, but in many cases it can be hard to overcome those dark feelings.
In one case, my Father’s boss was diagnosed with depression about two years ago. He was given the state-of-the-art treatment such as strong medication and even shock therepy. He was hospitalized many times and was in and out all the time. Sadly, he took his life.
I seem to be avoiding your question…..Do you mean a sin against the Roman Catholic Church or by God’s Law?