“…For example, a search in PsycINFO and MEDLINE found only eight studies on the differences between depressed children or adolescents and controls on serotonin levels or on the correlation between their serotonin levels and their degree of depression (Gerhard, Naumann, Kluge, & Blanz, 2002;Hughes, Petty, Sheikha, & Kramer, 1996;Modai et al, 1989;Nobile et al, 1999;Pliszka, Rogeness, Renner, Sherman, & Broussard, 1988;Rogeness, Mitchell, Custer, & Harris, 1985;Tao & Li, 2015;Tyano et al, 2006). The results of these few studies are, in general, contrary to the serotonin deficiency hypothesis or, at best, inconsistent.…”