Schnitker and Emmons (2007) found evidence for an inverse relationship between patience and negative affect and between patience and depression, but a positive relationship between patience and self-reports of certain negative health outcomes, including headaches, acne, and ulcers.
They found that trait stability increased from a correlation .31 in childhood to .54 during the college years, to .64 at age 30, and then it reached a plateau around .74 between the from age 50 until the age of 70. What we can infer from these results is that personality seems to stabilize with increasing age.
I'm pleased to report that only 73% of my personality was formed by age 5. My rampant paranoia, raging ego, and desperate need to flout social convention all kicked in at a later age. Furthermore, that percentage may drop, because I'm only 54, and my personality may still not be fully formed. I may add obsession and compulsion to my repertoire.