This study seeks to determine the prevalence of psychiatric morbidity within a medical intensive care unit, examine its correlation with the various physiological parameters and delineate any clinical predictors for psychiatric morbidity. Seventy-seven patients who gave informed consent were administered the General Health Questionnaire (GHQ), Acute Physiological And Chronic Health Evaluation II (APACHE II) and thyroid function tests were performed. A high prevalence of psychiatric morbidity was found (36.4%). However, no statistically significant association was found between psychiatric morbidity and gender, age, APACHE II scores and thyroid function indices. Nevertheless, it is hoped that the index of suspicion for psychiatric morbidity can be raised in order to optimise the clinical management of patients within this setting.