This study examines stress, coping, and regimen adherence as determinants o
f chronic and transient metabolic control in diabetes. We also examine the
interaction of biologic vulnerability and psychosocial risk factors to see
if Type 1 (insulin dependent diabetes mellitus) or Type 2 (noninsulin depen
dent diabetes mellitus) diabetes had greater responsiveness to psychosocial
risk factors. Analyses of data from insulin-treated adults with Type 1 (N
= 57) and Type 2 (N = 61) diabetes supported the biopsychosocial model. For
Type 1 diabetes, self-controlling persons had better glycemic control and
emotional persons had worse (because of differences in stress). All of thes
e associations were mediated by regimen compliance. For Type 2 diabetes, se
lf-controlling persons had better glycemic control for reasons other than r
egimen compliance. There was an interaction between biologic and psychosoci
al factors, with psychosocial factors accounting for more variance in glyce
mic control within Type 1 patients. Stable psychosocial resources (i.e., ed
ucation, being married and positive coping styles) were associated with bet
ter chronic glycemic control, while stress and regimen nonadherence were as
sociated with worse transient glycemic control.