Evaluating cumulated research. I: The inadequacy of traditional methods.

Virtually all reviews of cumulated studies rely on statistical significance as a criterion for evaluating the reproducibility of the phenomenon under review. Despite its nearly universal application, that criterion is entirely inadequate: Its application is very likely to lead a reviewer to conclude that a phenomenon does not discriminate patients from controls when, in fact, it does do so. The reviewer is, paradoxically, more likely to draw this incorrect conclusion as more studies become available for review. It can lead a reviewer to conclude that one phenomenon is more discriminating than another when the opposite is actually true. Fortunately, procedures that do not distort the review process are available; some of these are briefly discussed.

Factors determining the severity of pathological gambling in males.

In extending the implications of our earlier research, we found that a measure of impulsivity developed by Barratt (1965) differentiated recovering, male pathological gamblers (N = 12; mean age = 48.9 years) from male control subjects (N = 15; mean age = 43.3 years). Among the gamblers themselves, however, this measure of impulsivity did not correlate with an index of the social and familial disruption engendered by past gambling. In contrast, a measure of one facet of the gamblers' cognitive style (the TF subscale of the Myers-Briggs Inventory) did correlate with this index of gambling-induced disruption but did not differentiate gamblers from controls. These results, as well as other findings, are discussed in the context of previous research and with regard to the inferential limits imposed by studies of this kind.

Uric acid level increases in humans engaged in gambling: a preliminary report.

The effect of gambling and gaming on plasma levels of uric acid was studied. Blood samples were obtained from normal subjects while they gambled for money or while they played checkers without betting. There was an interaction of time and activity reflecting primarily an association of increased uric acid levels during gambling over time, compared with gaming and relaxation. This indicates that gambling can increase plasma levels of uric acid.

Behavioral restraint and symptoms of attention deficit disorder in alcoholics and pathological gamblers.

Adult alcoholics as well as pathological gamblers reported that, as children, they had higher than control levels of attention deficit disorder-related behaviors. On the other hand, alcoholics and only a subset of gamblers showed deficits in a test of behavioral restraint.

Attention deficit disorder and pathological gambling.

To examine the possibility that pathological gambling is related to the deficits in impulse control associated with attention deficit disorder, 14 pathological gamblers and 16 controls were administered questionnaires concerning their childhood behaviors. These self-reports indicated a strong correlation between pathological gambling and childhood behaviors related to attention deficit disorder.

Dopamine and schizophrenia: an analysis of the theory.

The postulated relationship of dopamine to schizophrenia ranks among the most important contemporary theories pertinent to the biological bases of behavior. However, as an examination of the relevant research literature makes clear, the theory has not yet been convincingly validated. This lack of validation is due, in part, to a failure to address the following questions: Is dopamine hyperactivity an etiological and/or a symptom factor in schizophrenia; do laboratory measures used to test the theory truly parallel the relevant clinical phenomena; is attenuated dopamine activity a necessary and/or sufficient condition for remission of schizophrenic symptoms? Analysis of these questions not only provides a departure point for examining the theory, but sets the stage for a reformulation of the theory itself.

Analysis of physiological mechanism in psychopharmacology.

Analysis of the mechanisms underlying the clinical effects of different drugs is a vital part of psychopharmacology. It is fair to say, however, that such analyses have thus far met with little success. This lack of success can be traced to a variety of sources that have flawed the analytical process itself. Detailed examination of these sources not only illuminates the nature of the flaws they engender, but suggests ways in which the analytic process can be modified so as to be a more fruitful one.

Effects of diazepam on operant behavior in man.

The effects of diazepam (10 mg orally) on the responding of normal human volunteers was studied in a procedure that involved the maintenance of operant behavior by monetary reinforcement and its suppression by monetary loss (punishment). Diazepam produced an antipunishment effect as shown by an increase in behavior suppressed by monetary loss. An analogy to animal procedures that selectively detect antianxiety drugs is apparent.

Stimulus efficacy, chlorpromazine, and schizophrenia.

Stimulus efficacy can be defined in terms of rat least two variables: Proximity of a stimulus to reinforcement and the association of a stimulus with reinforcements of different magnitudes. The behavioral effects of chlorpromazine were found to be significantly modulated by stimulus efficacy and increases in efficacy attenuated drug effect. The relevance of this finding to various conjectures about the deficits seen in schizophrenia is discussed.

Ontogenetic dissociation of two classes of habituation.

The rates of decrement of two classes of response (an elicited startle reflex and emitted exploratory behavior) were determined in rats of two different ages (15 and 36 days). The rate of decrement in the startle reflex was not clearly differentiated as a function of age. In contrast, there was no evidence of habituation of exploration in the younger animals, whereas the older rats uniformly showed profound response decrements. This ontogenetic dissociation of the two instances of response decrement indicates that accounts of both instances in terms of a common process called habituation may be unwarranted. In addition, these data, in conjunction with earlier findings, indirectly support the possibility that reflex decrements may be relatively more dependent on brain serotonin whereas decrements in exploration may be more dependent on normal cholinergic activity in brain.

Retention deficit correlated with a deficit in the corticoid response to stress.

Previous research has indicated that intracerebral injection of potassium chloride, and the resultant electrical silence of the brain, lead to the attenuation of a previously conditioned emotional response; this response may reflect conditioned fear. The data reported here indicate that the normal mobilization of corticosteroids, perhaps a second index of emotionality, is also attenuated by such injections.