Hi Embodied,
The first precept a buddhist undertakes is to refrain from destroying the life of a living being (including their own). To be born as a human is very rare and one must have done much meritorious deeds in past lives. A human birth is the most ideal existence to practise Dhamma and attain magga phala. So, to prematurely terminate one’s life would certainly bring forth much unwholesome kamma vipaka. I heard of some sayings (don’t know how true) of people who commit suicide would have to go through the same process of dying until their vitality is truly exhausted.