SCT and social phobia: For example, one clinical trial failed to detect significantly improvement of social phobia by using CCK-tetrapeptide (CCK-4) (Katzman et al., 2004), and many double-blind placebo-controlled studies using secretin to alleviate autism symptoms infusion have also been failed (Esch and Carr, 2004; Malone et al., 2005; Krishnaswami et al., 2011; Lyra et al., 2017) even though the existence of one early study reporting the beneficial effects of secretin (Horvath et al., 1998).