Two approaches on which published studies have been undertaken are holding therapy and dyadic developmental psychotherapy. Each of these non-randomized studies concluded that the treatment method studied was effective. Both the APSAC Task Force and Prior and Glaser cite and criticize the one published study on holding therapy undertaken by Myeroff et al., which "purports to be an evaluation of holding therapy". This study covers the "across the lap" approach, described as "not restraint" by Howe and Fearnley but "being held whilst unable to gain release." Prior and Glaser state that although the Myeroff study claims it is based on attachment theory, the theoretical basis for the treatment is in fact Zaslow.