This research shows the utility of systematic data-gathering from older people and of a statistical analysis procedure for interpreting the data. Four cases of institutionalized older people are presented, and their scores of depressive symptomatology over a period of one to two years is analyzed. Time-series analysis showed a significant positive trend of depression symptomatology in two of the cases, perhaps too subtle for detection in routine clinical check-up, but statistically verifiable. In one of these cases, none of the factors of the scale stands out, despite the fact that the general index shows a statistically significant change over the 36 observations made, so that the results obtained are related to the syndrome of depletion or exhaustion. In the second of the cases, we detect a significant change in the depressive mood factor, which may indicate a subclinical depressive form in its initial stages. Continuous registers can reveal valuable information about situations and progress in the evolution of an older person's mood, with regard to natural development, the prelude to a mood disorder, or follow-up in clinical cases.