Modifies the existing exemption from requiring a determination of what constitutes prima facie evidence of neglect where a parent or guardian engages in substance abuse or substantial manifestation of irrationality but is voluntarily and regularly participating in a recognized rehabilitative program so as to require the parent or guardian to have voluntarily participated in and to have successfully completed such a program and to have been verifiably rehabilitated for an uninterrupted period of one year immediately prior to the hearing date, before such exemption applies.