From a biological perspective, what makes the brain decide it wants/needs to die? Why does it get stronger as time progresses if left untreated? Why does the urge come back periodically after "treatment," even if everything is going right in a person's life? Why is it even stronger after an attempt? Is it inflammation of the limbic system? Some other neuronal inflammation? Deficiency in some sort of vital hormone? Side effect of medication? Side effect of a potential mental illness? Something else? Mixture of the above, or does it also depend on a sociological perspective?