Treatment of alcohol organic mental disorder with piracetam

Piracetam for dementia or cognitive impairment

OBJECTIVES

To determine the clinical efficacy of piracetam for the features of dementia or cognitive impairment, classified according to the major subtypes of dementia: vascular, Alzheimer's disease or mixed vascular and Alzheimer's disease or unclassified dementia or cognitive impairment not fulfilling the criteria for dementia.

SEARCH STRATEGY

The Cochrane Dementia and Cognitive Impairment Group Register of Clinical Trials was searched using the terms "piracetam", "nootropic" and "2-oxo-l-pyrrolidine acetamide". Electronic bibliographic databases including Medline, Embase, PychLit, Current Contents, Sociofile were searched back to 1966 with the terms piracetam, nootropics, 2-oxo-1-pyrrolidine and trials. In addition the pharmaceutical company responsible for marketing most of the piracetam worldwide, UCB Pharma, provided a comprehensive list of abstracts, which included many unpublished studies. As many of these unpublished, placebo control studies will be reviewed as possible.

SELECTION CRITERIA

All unconfounded trials specified as randomised in which treatment with piracetam was administered for more than a day and compared with placebo in patients with dementia of the Alzheimer's type, vascular dementia or mixed vascular and Alzheimer's disease or uncalssified dementia or cognitive impairment not fulfilling the criteria for dementia.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers. Each study was independently verified as fulfilling the inclusion criteria. Studies were rated for methodological quality by assessment of blinding and loss before analysis as described by Jadad et al. (1996). Studies were pooled if appropriate and possible, and the pooled odds ratios (95%CI) or the average differences (95%CI) were estimated. Where possible, intention-to-treat data were used. Sensitivity analyses were performed to determine if successive elimination of those studies performing most poorly on these quality criteria changed the effect estimate.

MAIN RESULTS

Unfortunately, many of these studies were crossover in design and data were unavailable from the first period. In many other studies data were not able to be extracted from the first period. From the data that were pooled there was only one outcome where significant amounts of evidence were available, Global Impression of Change. There was evidence of heterogeneity in the results from the individual studies, Chi squared test = 20.8 (df=5). Using a fixed effects model the odds ratio for improvement in the Piracetem group compared with the Placebo group was 3.55, [95% CI][2.45, 5.16]. If a random effects model was used the odds ratio was 3.47 [1.29, 9.30]. If one single-blind study was excluded, the fixed effects model yielded an odds ratio of 3.36 [2.29, 4.99] and if a random effects model was applied then the odds ratio was 2.89 [1.01, 8.24]. The evidence of effects on cognition and other measures, was inconclusive.

REVIEWER'S CONCLUSIONS

At this stage the evidence available from the published literature does not support the use of Piracetem in the treatment of people with dementia or cognitive impairment because effects were found only on global impression of change but not on any of the more specific measures. There is a need for further evaluation of piracetam by : 1) Obtaining the data from these studies for an individual patient database review, 2) Performing a randomised trial of Piracetam in patients with diagnoses made by currently accepted diagnostic criteria. Piracetam should be trialled for a period of at least 6 months and preferably longer. Specific cognitive instruments which are sensitive to change, Clinician Global Impression of Change, levels of dependency and caregiver quality of life scales should also be incorporated in such a study.

Behavioral screening for cognition enhancers: from indiscriminate to valid testing: Part I

Preclinical efforts to detect and characterize potential cognition enhancers appear to have been dominated by a strategy of demonstrating a wide variety of apparently beneficial behavioral effects with little attention given to the specific psychological mechanisms underlying behavioral enhancement. In particular, the question of whether or not behavioral facilitation is based on relevant mnemonic mechanisms and is independent of the stimulus properties and/or the motivational and attentional components of a task is not often considered. As a result, an overwhelming number of compounds have failed to produce the clinical effects predicted for them on the basis of preclinical research. The available data suggest that a more successful approach requires deductive research strategies rather than the indiscriminate accumulation of apparently beneficial effects in a variety of behavioral tasks and animal models. The first step towards such an approach is a systematic and rigorous evaluation of the different aspects of validity for the models most frequently used in preclinical research. It is concluded that a combination of good construct validity and good face validity represents a necessary condition for screening tests with predictive validity, and that the most popular paradigms fail to fulfil these criteria. Future screening programs for cognition enhancers will probably be characterized by a depreciation of "fast and dirty tests" in favor of approaches focussing on the validity of the effects of potential cognition enhancers.

Taking stock of cognition enhancers

An increasing number of structurally heterogeneous compounds, which may act via very different categories of neuronal mechanisms, have been proposed to facilitate attentional abilities and acquisition, storage and retrieval of information, and/or to attenuate the impairments of such cognitive functions associated with age or dementia. In this article, Martin Sarter briefly reviews the data on putative cognition enhancers and examines the possible bases for the discrepancy between preclinical predictions of efficacy and the fact that unequivocal demonstration of drug-induced cognition enhancement in humans has only rarely been reported. Previous preclinical research strategies appear to have focused on the demonstration of drug effects in a wide variety of tests of uncertain validity, rather than on determination of the specific psychological and neurobiological processes affected by putative cognition enhancers. Some criteria are proposed for evaluating the validity of preclinical tests for cognition enhancers.