“…In addition to crisis theory, a number of other theoretical frameworks may be useful in explaining adaptation processes, including judgment theories such as Helson's adaptation level theory (Helson, 1964;De Haes and Van Knippenberg, 1985;Brickman et al, 1978;Parducci, 1995) and social comparison theories (Festinger, 1954;Taylor and Lobel, 1989;Van der Zee et al, 1995); control theories (Powers, 1978) such as the self-regulation theory (Carver and Scheier, 1982;Leventhal and Nerenz, 1983); discrepancy theories (Calman, 1984;Michalos, 1985); uncertainty in illness theory (Mishel 1988;Padilla et al, 1992); stresscoping theories (Lazarus and Folkman, 1984;Folkman, 1997); and response shift theories (Breetvelt and Van Dam, 1991;Howard et al, 1979;Golembiewski et al, 1976;Sprangers and Schwartz, 1999). While these theories vary widely in level of abstraction and breadth of coverage, they make important and convincing attempts to explain changes in perceived QL.…”