“…Studies of biological variables have yet to identify consistent differences between chronic and nonchronic groups. Studies of hypercortisolemia (Gasto et al, 1994;Miller, Norman, & Dow, 1986), growth hormone secretion (Maes, Vandewoude, Maes, Schott, & Cosyns, 1989), sleep physiology (Appelboom-Fondu, Kerkhofs, & Mendlewicz, 1988), and neurotransmitter functioning (Ravindran, Bialik, Brown, & Lapierre, 1994) revealed that the abnormalities in chronic depression are similar to or less pronounced than those found in nonchronic cases (see Riso, Miyatake, & Thase, 2002, for a review). Some evidence has been found for increased rates of subclinical hypothyroidism for subgroups of individuals with chronic depression (Scott, Barker, & Eccleston, 1988;Tappy, Randin, Schwed, Werthermimer, & Memarchand-Beraud, 1987).…”