The development of a 29-item self-report inventory to screen for non-adaptiveness with an episode or a history of major mental disorder in the army is described. Initially, a 58-item inventory was constructed. However, through a pilot study 46 items remained. The reliability and validity test of the 46-item inventory was then carried out on 357 patients and 126 controls. Firstly, item analyses were performed which showed 12 items that distinguished between schizophrenic patients and controls, 9 items that distinguished between depressive patients and controls and 8 items that distinguished between manic patients and controls. A final 29-item inventory was found to have satisfactory reliability, sensitivity and specificity. The analyses of the best cut-off scores using the receiver-operating-characteristic curve suggested a score of 3 for the Schizophrenia Scale, 2 for the Depression Scale, and 3 for the Mania Scale. The inventory can be completed in about 5 to 10 minutes and has a simple method of scoring. The use of this screening inventory in the army is discussed.