Michael Vainder

Go–no-go performance in pathological gamblers

Previous neuropsychological studies demonstrated various deficits of impulse control in pathological gamblers (PGs). However, there are limited data available on response-inhibition impairment among PGs. The present study attempted to assess response inhibition in untreated PGs (N=83), in comparison with normal subjects (N=84). Go/no-go and target-detection conditions of a computerized task were used as a measure of response-inhibition ability. A repeated measures analysis of covariance (ANCOVA-RM) was used with response time, variability of response time, and number of false alarms and misses as dependent measures; group (PG and controls) as the between-subjects measure; condition (target detection or go/no-go) and time slice (first and second in each condition) as repeated measures within-subject factors; and educational level as a covariate. Our results showed that PGs were significantly more impaired in both target detection and go/no-go task performance than controls. The PGs had significantly more false alarms and misses than controls, and they were slower and less consistent in their responses.

Speed-Accuracy Tradeoff in Decision-Making Performance among Pathological Gamblers

Background: Pathological gambling is classified as an impulse control disorder in the DSM-IV-TR; however, few studies have investigated the relationship between gambling behavior and impulsive decision-making in time-non-limited situations. Methods: The subjects performed the Matching Familiar Figures Test (MFFT). The MFFT investigated the reflection-impulsivity dimension in pathological gamblers (n = 82) and demographically matched healthy subjects (n = 82).Results:Our study demonstrated that pathological gamblers had a significantly higher rate of errors than healthy controls (p = 0.01) but were not different in terms of response time (p = 0.49). We found a similar power of correlation between the number of errors and response time in both pathological gamblers and controls. We may conclude that impaired performance of our pathological gamblers as compared to controls in a situation without time limit pressure cannot be explained by a trade-off of greater speed at the cost of less accuracy. Conclusions: The results of our study showed that pathological gamblers tend to make more errors but do not exhibit quicker responses as compared to the control group. Diminished MFFT performance in pathological gamblers as compared to controls supports findings of previous studies which show that pathological gamblers have impaired decision-making. Further controlled studies with a larger sample size which examine MFFT performance in pathological gamblers are necessary to confirm our results.

Can Minnesota Multiphasic Personality Inventory-2 predict response to selective serotonin reuptake inhibitors in depressed outpatients?

There is growing evidence that individual differences among patients with major depressive disorder (MDD) on psychological and demographic measures may predict the therapeutic response to selective serotonin reuptake inhibitors (SSRIs). In this retrospective chart review, 108 outpatients with current major depressive episodes were treated with citalopram, paroxetine, or fluvoxamine. The Hamilton Depression Rating Scale and the Minnesota Multiphasic Personality Inventory-2 were administered before and after 8 weeks of SSRIs treatment. Clinical response was defined as a 50% or greater decrease in the 17-item Hamilton Depression Rating Scale total score (final visit minus baseline). This naturalistic short-term follow-up outcome study demonstrates that among depressive outpatients who responded to an 8-week trial, 57.4% achieved a good response to SSRIs. Statistical analysis showed that SSRI treatment may be 3.03 times more advantageous for MDD outpatients who are younger than 39 years. The patients with an elevated score of above 66T on the Social Introversion Minnesota Multiphasic Personality Inventory-2 scale are approximately 0.37 times as likely to be SSRI responders as are patients with a Social Introversion score less than 66T. Thus, it seems that in MDD outpatient age is the strongest predictor of response to SSRIs.

VARIABILITY OF COLOR CHOICE IN THE LUSCHER COLOR TEST-SEX DIFFERENCES '

In this preliminary investigation of variability of responses on the Lüscher Color Test, subjects were 567 volunteers administered the test twice with a 10-min. interval between them. Two hypotheses were tested: (a) that variability of responses attests to the personality of the respondent (tested by the relations of variability and MMPI scale scores), and (b) variability of responses is based on learning the tests content. As such, mens scores should be more variable than womens. Analysis showed that variability was not correlated with scores for personality on the MMPI scales. Mens scores are more variable than womens, but only until age 45.

The role of gender in association between inhibition capacities and risky decision making

Background Research on the association between decision making and inhibition abilities has exhibited fundamental controversies. Some authors claim that inhibition abilities are an integral part of the decision-making process, whereas others suggest that the decision-making process does not operate in close association with inhibition abilities. Can gender explain variations in risky decisions via inhibition influences? Purpose The purpose of the present study was to explore the associations between response inhibition, reflection inhibition, interference inhibition, and decision-making processes in men and women. Methods To this end, 46 women and 46 men were assessed by the Go/NoGo task, a measure of response inhibition, by the Matching Familiar Figure Test, a measure of reflection inhibition; and by the Stroop task, a measure of interference inhibition. Results No differences were detected in these measures between groups. The net score of the performance on the last section of the Iowa Gambling Task choices did not correlate with the inhibition measures in the two groups. We did not discover any significant main effects of gender on the association between these measures. Conclusion These findings do not support the hypothesis that risky decisions are due to impaired inhibitory control. Further studies are needed to identify the cognitive mechanisms involved in the tendency to make risky decisions.