Caitlin, a philosophy professor at California State University, said the loneliest moment in her life occurred more than a decade ago, when she returned home from a semester abroad in Italy. While staying in Florence, her Italian improved greatly and she developed a great interest in art. She changed intellectually and emotionally. Back in a working-class town in New Jersey, she had much to share with her friends and family, but she found them intellectually dull, and Caitlin felt intensely alone. 　　Psychologists say that the process of readjusting and reintegrating into one’s own family culture after living in a different culture for a period of time can lead to feelings…