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.
Out of the group of 250 --134 had symptoms of possible personality disorder, some with more symptoms than others. The rest of the students were controls in the study, and had no signs of personality disorders. The data he presents are from the students' first four years in college, when they were between 18 and 21 years old. Three times during the four-year study period, students were tested for personality disorder symptoms.