The developmental pathways leading to personality disorders are poorly understood, but clues to these pathways come from recent research on personality disorders and normal personality development in childhood and adolescence. (cambridge.org)
I think he has a quite normal personality even being open and has a good sense of humour. (justarsenal.com)
Capturing abnormal personality with normal personality inventories: An item response theory approach to the understanding of psychopathy (cambridge.org)