Groups of depressed patients were given the EPI both before and after recovery. While depressed, they obtained spuriously high N scores and spuriously low E scores because they tended to rate their current state of mind rather than their normal selves. It was found, however, that the addition of a further sentence to the test instructions largely prevented this and enabled them to assess their normal personalities surprisingly well even when quite deeply depressed. It is therefore recommended that the sentence in question—"Try to disregard your illness when answering these questions and answer `YES' or `NO' according to how you feel or behave when you are your usual self."—should always be added to the instructions when testing patients with temporary mood disturbances.
The scores obtained by patients after recovery differed from those quoted for the normal population in the expected ways. Neurotic depressives were more neurotic and introverted than normals or psychotic depressives; psychotic depressives were more neurotic than normals but neither more nor less extraverted, and were less neurotic and more extraverted than neurotic depressives. Firm conclusions about the personalities of those who develop depressive illnesses, can, however, only be made on the basis of community studies.