((a)) ** .—** For the purposes of this chapter, any veteran of World War II, the Korean conflict, the Vietnam era, or the Persian Gulf War who developed an active psychosis (1) within two years after discharge or release from the active military, naval, or air service, and (2) before , in the case of a veteran of World War II, before , in the case of a veteran of the Korean conflict, before , in the case of a Vietnam era veteran, or before the end of the two-year period beginning on the last day of the Persian Gulf War, in the case of a veteran of the Persian Gulf War, shall be deemed to have incurred such disability in the active military, naval, or air service.
((b)) ** .—** For purposes of this chapter, any veteran of the Persian Gulf War who develops an active mental illness (other than psychosis) shall be deemed to have incurred such disability in the active military, naval, or air service if such veteran develops such disability—
((1)) within two years after discharge or release from the active military, naval, or air service; and
((2)) before the end of the two-year period beginning on the last day of the Persian Gulf War.