Unrecognized glucose intolerance is not associated with depression. Screening for Impaired Glucose Tolerance study 3 (SIGT 3).

AIMS: To understand the metabolic and temporal links in the relationship between diabetes and depression, we determined the association between depressive symptoms and unrecognized glucose intolerance.
METHODS: In a cross-sectional study, 1047 subjects without known diabetes were screened for diabetes or pre-diabetes using the oral glucose tolerance test and for depressive symptoms using the Patient Health Questionnaire (PHQ).
RESULTS: Mean age was 48 years, body mass index 30 kg/m(2); 63% were female, 54% black, 11% previously treated for depression and 10% currently treated; 5% had diabetes and 34% pre-diabetes. Median PHQ score was 2 (interquartile range 0-5). Depressive symptoms did not increase with worsening glucose tolerance, after adjusting for age, sex, ethnicity, body mass index, family history, exercise, education and depression treatment.
CONCLUSIONS: There is no association between depressive symptoms and unrecognized glucose intolerance. However, it remains possible that diagnosed diabetes, with its attendant health concerns, management issues, and/or biological changes, may be a risk for subsequent development of depression. Thus, patients with newly diagnosed diabetes should be counselled appropriately and monitored for the development of depression.