ABSTRACT
Explicit memory and two forms of implicit memory, repetition priming and cognitive skill learning, were examined in twenty-four schizophrenic patients and twenty-four normal control subjects previously matched for sex, age, and educational level. Two explicit tasks, free recall and frequency monitoring, and two implicit tasks, word completion and the Tower of Toronto puzzle, a variant of the Tower of Hanoi puzzle, were selected. The performance of schizophrenic patients was impaired in both explicit tasks, whereas repetition priming was intact; in the Tower of Toronto puzzle, a deficit was observed in problem solving, but not in skill learning. This dissociation between explicit and implicit memory is not entirely consistent with the hypothesis of a deficiency in effort-demanding information processing. It could be better accommodated by a model of a disturbance in the internal representation of context.
Subject(s)
Attention , Cognition Disorders/diagnosis , Mental Recall , Problem Solving , Schizophrenia/diagnosis , Schizophrenic Psychology , Verbal Learning , Adolescent , Adult , Cognition Disorders/psychology , Decision Trees , Female , Humans , Male , Psychomotor PerformanceABSTRACT
Explicit memory and repetition priming, a form of implicit memory, were examined in depressed patients and controls. Explicit memory of depressed patients was severely impaired, whereas repetition priming was intact. These results are consistent with the hypothesis that the impairment of memory in depression is linked to a failure of effort-demanding cognitive processes. Repetition priming might be useful in differentiating between depression and dementia.
Subject(s)
Depressive Disorder/psychology , Memory , Psychological Tests , Dementia/diagnosis , Dementia/psychology , Depressive Disorder/diagnosis , Diagnosis, Differential , Humans , Memory Disorders/classification , Memory Disorders/diagnosis , Memory Disorders/psychology , Mental Recall , Wechsler ScalesABSTRACT
The effects of scopolamine, an anticholinergic drug, of trimipramine, a tricyclic antidepressant with both anticholinergic and sedative properties, of diazepam and a placebo, on explicit memory and repetition priming were assessed using a free-recall task and a word-stem completion task. Forty-eight healthy volunteers took part in this double-blind study. Diazepam provoked a dissociation between free recall, which was profoundly impaired, and word completion, which was spared. No significant changes in memory performances were observed in the scopolamine group; however, a significant correlation between explicit and implicit memory performances was observed in this group. At the low dose used, the effects of trimipramine on memory were mild. The results suggest that the cholinergic system is involved in the priming effect.
Subject(s)
Diazepam/pharmacology , Memory/drug effects , Scopolamine/pharmacology , Trimipramine/pharmacology , Adult , Female , Humans , MaleABSTRACT
The effects of 0.2 mg/kg orally administered diazepam and of a placebo on explicit memory, implicit and knowledge memory were assessed using a free recall task, a word-stem completion task and two category-generation tasks. Twenty four healthy volunteers took part in this double-blind study. Diazepam impaired explicit but not implicit memory. The drug also spared knowledge memory. Explicit memory was linked with the diazepam-induced sedation and with the self-rated affective load of to-be remembered words, but implicit memory was not. The diazepam-induced dissociation between explicit and implicit memory supports the notion of two distinct forms of memory and reproduced the dissociation observed in organic amnesia.
