The core problem seems to be that he is most vulnerable to depressive feelings when he is unoccupied but he keeps insisting that he can not find an occupation because he can't find his mission in life, and nothing else but this elusive mission interests him very much. Much rumination and sterile circularity. I have tried some strategies (including confidence-building) to break the circularity with moderatie success and am interested in other ideas from you. He seems to be optinmally medicated.