Memory in depression

Abstract

The memory of clinically depressed psychiatric patients was compared with that of anxious patients and control subjects. The depressed patients had impaired ability to learn new material and to remember past public events; they retained information in memory as well as controls and did not have a more conservative response bias. These impairments were not attributable to the psychotropic medication the patients were receiving or to the after-effects of ECT. The retarded depressed patients were most severely ill and most impaired; the neurotic patients were only impaired on the more difficult tests. The anxious patients' scores were not significantly different from those of either the depressed or control subjects. The relative effects of depression and anxiety on performance were assessed using regression analysis; depression was related to performance on the easier tests, whilst something common to both depression and anxiety was related to performance on the more difficult tests. The retarded depressed subjects reported more cognitive failures than the other subjects whilst both the depressed and anxious subjects complained of significant deterioration in memory. There were statistically significant, although modest, correlations between these self-assessments of memory and performance on the memory tests. Anxiety was related to self-assessments of memory but depression was not. The memory of depressed general practice patients for information given to them by their general practitioners was investigated directly; they did not in fact have impaired memories in this everyday situation. These results suggest that the degree of memory impairment shown in depression depends both on the severity of depression and the difficulty of the task. They are discussed In the light of the suggestion by Johnson and Magaro (1987) that memory Impairments may not be specific to depression but instead be related to the overall level of psychopathology. The working memory capacity model of memory in anxiety (Eysenck, 1982) is also discussed and extended to depression, as is a model developed by Williams and Teasdale (1982) which argues that effort expenditure is largely determined by perceived task difficulty. Finally, it is concluded that the best understanding of memory in depression will come from the concurrent use of experimental studies, metamemory questionnaires and studies of memory performance in everyday life.