Previous research examined "general instability" and "psychopathy" scales, derived from the 16PF, in terms of Foulds' criteria of content, group differentiation, change over time, and score distributions. When the external criterion of a newly validated measure of psychiatric mood state (the DSSI/sAD) was used, it was confirmed in both a patient and a normal group that the "general instability" scale is related significantly to symptomatology, while the "psychopathy" scale is relatively independent of present state.