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Biomedical subjects

S H Stewart

Publications and source records attributed to S H Stewart.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cognitive behavioural therapy and pharmacotherapy: complementary or contradictory approaches to the treatment of anxiety?

Considerable controversy exists regarding the practice of combining Cognitive Behavioural Therapy (CBT) with Pharmacotherapy (PT) in the management of anxiety. This paper considers whether these two forms of treating anxiety disorders can be effectively combined to enhance treatment outcome. Despite the theoretical appeal of a combined approach, a critical review of treatment outcome findings across CBT and various anxiolytic medications and their combination, suggests a failure of these treatments to operate in a complementary fashion. A detrimental impact of anxiolytic medication on CBT outcome is particularly salient for high potency benzodiazepines. Low potency benzodiazepines and antidepressants generally have a negligible impact with no clear evidence of treatment enhancement and some negative combined treatment effects on medication withdrawal and at long-term follow-up. Thus, we address potential mechanisms that may explain this treatment noncomplementarity and in some cases, treatment incompatibility. Cognitive factors influencing treatment outcome (catastrophic beliefs, self-efficacy, selective attention, and memory) are highlighted in view of the empirically supported mediating role of these variables in accounting for treatment responsiveness. Potential effects of anxiolytic medication on cognitive change in CBT are postulated. A number of suggestions for future research and clinical practice are proposed on the basis of this review.

Anti-Anxiety Agents↗
PubMed1998

An examination of differences in the time course of oxazepam's effects on implicit vs explicit memory.

The present study was designed to examine the effects of oxazepam on implicit vs explicit memory processes, as a function of this drug's time course. The effects of oxazepam (30 mg) or placebo on directly comparable tests of implicit memory (word stem completion) and explicit memory (cued recall) were examined at three time points: 100 min post-drug administration (prior to the theoretical peak plasma concentration of oxazepam; i.e.'pre-peak' condition), 170 min post-drug (close to theoretical peak; i.e. 'peak' condition) or 240 min post-drug (following theoretical peak: i.e. 'post-peak' condition). Sixty healthy volunteers were randomly assigned to either the drug condition or the placebo condition in a double-blind design and were tested on both memory tests at one of the three time points. In the 'pre-peak' condition, oxazepam impaired cued recall performance relative to placebo but did not impair priming. In the 'peak' condition, oxazepam impaired performance on both memory tasks. In the 'post-peak' condition, cued recall performance in the oxazepam group remained significantly impaired relative to placebo. However, oxazepam-induced impairments in priming were only marginal, suggesting that oxazepam-induced impairments in implicit memory processes begin to wane following theoretical peak drug concentrations. The fact that oxazepam-induced priming impairments were significant only when the word stem completion task was administered close to peak plasma concentrations, supports the hypothesis that benzodiazepines exert time-dependent effects on implicit memory processes. The results also support the theoretical distinction between implicit and explicit memory processes, since the directly comparable implicit and explicit tasks showed different impairment curves over time.

Adolescent↗
PubMed1997

Effects of short-term food deprivation and chronic dietary restraint on the selective processing of appetitive-related cues.

OBJECTIVE: Selective processing of appetitive cues was investigated among food-deprived subjects and restrained eaters using the modified Stroop. METHOD: Thirty-two university students (25 females, 7 males) were randomly assigned to a 6-hr food deprivation (FD) or a no food deprivation (NFD) condition. Subjects were also divided into three restrained eating groups-high (HR), moderate (MR), and low (LR)-according to Restraint Scale scores. Subjects color named sets of food, alcohol, and leisure control words. Stroop color-naming latencies were submitted to 2 x 3 (Food Deprivation Condition x Word Type) and 3 x 3 (Restrained Eating Group x Word Type) repeated measures analyses of variance (ANOVAs). RESULTS: Food deprivation failed to produce longer latencies for food or alcohol words relative to control words. However, HR status was associated with significantly longer latencies for both food and alcohol, relative to control, words. DISCUSSION: Chronic dietary restraint but not short-term food deprivation was associated with selective processing of appetitive cues. The results have implications for understanding food preoccupation and risk for alcohol abuse in restrained eaters.

Attention↗
PubMed1997

Anxiety sensitivity and self-reported reasons for drug use.

Two studies examined the relationships between anxiety sensitivity (AS), drug use, and reasons for drug use. In Study 1, 229 university students (57% F) completed the Anxiety Sensitivity Index (ASI) and a drug use survey, assessing use of a variety of drugs within the last month, and coping reasons for drug use. Consistent with a modified tension-reduction hypothesis, ASI scores were positively correlated with the number of both anxiety- and depression-related reasons for drug use endorsed. In Study 2, 219 university students (74% F) completed the ASI and a drug use survey, assessing use of several drugs (e.g., alcohol, cigarettes, caffeine, and marijuana/hashish) within the last year, and primary reasons (coping, affiliative, or enhancement) for the use of each drug. Marijuana/hashish users reported lower ASI scores than non-users supporting a negative relation between AS and the use of cannabis. ASI scores were positively correlated with the use of alcohol primarily to cope, and negatively correlated with the use of alcohol primarily to affiliate, among both gender groups, and ASI scores were positively correlated with the use of nicotine primarily to cope among the females. Implications of these findings for understanding risk for abuse of stress-response-dampening drugs by high AS individuals are discussed.

Adaptation, Psychological↗
PubMed1997

Validation of a measure of excessive drinking: frequency per year that BAL exceeds 0.08%.

Although self-report data are generally evaluated as reliable, validity estimates for self-reported drinking behavior are not as favorable. A new method of measurement addressing problems currently associated with the questionable validity of self-report drinking information is introduced. Study 1 tests the correspondence between the new measure (occasions per year blood alcohol level exceeded 0.08%), traditional self-report measures, and laboratory alcohol consumption. The novel measure correlated most strongly with volume of alcohol consumed in the laboratory compared to the traditional measures. In Study 2 the novel measure was favored over a traditional measure when discriminating between the presence and absence of problem-drinking symptoms.

Adolescent↗
PubMed1996

Effects of oxazepam and lorazepam on implicit and explicit memory: evidence for possible influences of time course.

The effects of oxazepam (30 mg), lorazepam (2 mg), and placebo on implicit and explicit memory were studied in two testing cycles, 100 and 170 min after drug administration. Thirty healthy volunteers were randomly assigned to one of three groups (placebo, oxazepam, or lorazepam) in a double-blind, independent groups design. Drug groups were equivalent prior to drug administration on a variety of cognitive measures. Following drug administration, both oxazepam and lorazepam equally impaired performance on a cued-recall explicit memory task relative to placebo, at both testing cycles. Relative to placebo, lorazepam markedly impaired priming on a word-stem completion implicit memory task, at both testing cycles. Consistent with previous work, oxazepam failed to produce impairments in priming on the word-stem completion task at 100 min post-drug administration. However, oxazepam was found significantly to impair priming on this latter task relative to placebo, at close to theoretical peak plasma concentration (i.e., 170 min post-drug administration). Explanations for the observed detrimental effect of oxazepam on implicit memory task performance are considered, including: possible time-dependent effects related to the relative rate of absorption of these two benzodiazepines (BZs); and potential contamination of the implicit memory task by explicit memory strategies during the second testing cycle.

Adolescent↗
PubMed1996

Examination of a three-dimensional drinking motives questionnaire in a young adult university student sample.

The literature on drinking motives suggests that individuals drink for three distinct reasons: coping motives (CM: to reduce and/or avoid negative emotional states); social motives (SM: to affiliate with others); and enhancement motives (EM: to facilitate positive emotions). Cooper, Russell, Skinner and Windle (1992) [Psychological Assessment, 4, 123-132] developed a 3-dimensional self-report instrument, the Drinking Motives Questionnaire (DMQ), with subscales designed to assess relative frequency of drinking for each of these three motives. This study was designed to examine the psychometric properties of the DMQ in a large sample of young adult university students. Three hundred and fourteen students voluntarily served as subjects; 266 students (85% of the total sample; 196F and 70M) reported drinking on the DMQ. These students were divided into two age groups [20 yr and under (n = 117); 21 yr and older (n = 149)]. Analyses of variance indicated: (a) main effects of gender, with men scoring significantly higher on the DMQ-EM subscale and tending to score higher on the DMQ-SM subscale when compared to women; (b) a main effect of age group on the DMQ-EM subscale, with younger students scoring significantly higher than older students; and (c) a significant main effect of drinking motive, with the most relatively frequent drinking reported for SM and the least for CM overall. Although mild-to-moderate shared variance between subscales was noted, the three subscales of the DMQ were found to possess adequate-to-high levels of internal consistency. A confirmatory factor analysis (CFA) showed that the hypothesized 3-factor model provided a better fit than either a unidimensional or 2-factor model in explaining the underlying structure of the DMQ. Some suggestions for improvements in DMQ item content are made. The present results replicate and extend previous findings by Cooper and colleagues to a sample of university students, and support the utility of using the DMQ in future investigations of the drinking motives of young adults.

Adult↗
PubMed1996

Alcohol abuse in individuals exposed to trauma: a critical review.

In this article, the author critically reviews studies on the relationship between exposure to trauma, posttraumatic stress disorder (PTSD), and alcohol abuse. After establishing that strong relationships exist between exposure to traumatic events and alcohol problems, and particularly between the diagnoses of PTSD and alcoholism, the author discusses various factors, theories, and possible mechanisms to account for these associations. Moreover, she discusses applications of these findings to the assessment and treatment of people exposed to trauma who abuse alcohol. Finally, the author outlines novel methods for testing theoretical hypotheses and makes suggestions for methodological improvements in future research.

Alcoholism↗
PubMed1996

Ethanol-induced change in cardiac and endogenous opiate function and risk for alcoholism.

Susceptibility to alcoholism varies with age, gender, and familial background. Youthful nonalcoholic males with multigenerational family histories of male alcoholism seem at particular risk. Previous investigations suggest that such males are characterized by abnormal psychophysiological response, while sober and alcohol-intoxicated; additional recent studies indicate that the endogenous opiate systems are involved in mediating ethanol reinforcement and modulating intake. We first compared cardiac response to alcohol administration among young (mean = 22.8 years), nonalcoholic men and women with multigenerational, unigenerational, and negative family histories of alcohol dependence and abuse. Then, we compared the ethanol-induced cardiac response of the males in these three groups to that of currently alcohol-dependent older males and age-matched nonalcoholic male controls. Finally, we examined ethanol-induced change in plasma beta-endorphin and cortisol levels among a subset of the nonalcoholic males, divided into those with high and low levels of postethanol administration heart-rate increase. Nonalcoholic males with multigenerational family histories of male alcoholism were characterized by significantly higher [t(301) = 5.70, p < 0.0001, Cohen's d = 0.73] levels of ethanol-induced heart-rate increase than nonalcoholics from all other comparison groups. The magnitude of their increase matched that of current male alcohol-dependents. Nonalcoholic males with high levels of ethanol-induced heart-rate increase also produced significantly more plasma beta-endorphin after consuming alcohol. Peak production of beta-endorphin was highly correlated (r = 0.861, p < 0.001) with magnitude of heart-rate increase. A subset of those at risk for alcoholism may be characterized by sensitivity to ethanol-induced reward, marked by heightened ethanol-induced, heart-rate increase, mediated by ethanol stimulation of endogenous opiate production. This subset might contain those who, once alcoholic, would differentially benefit from treatment with opiate antagonists.

Adult↗
PubMed1995

A dose-response study of the effects of alcohol on the perceptions of pain and discomfort due to electric shock in men at high familial-genetic risk for alcoholism.

Alcoholics have previously been found to be more sensitive to painful stimulation than controls, and more sensitive to the pain-reducing effects of alcohol. The present study was designed to examine these effects in men at high familial-genetic risk for alcoholism and controls. Subjects were assigned to one of four alcohol doses [0.135 (active placebo), 0.50, 0.75, or 1.00 ml 95% USP alcohol/kg body weight]. Ratings of the amount of discomfort and pain experienced during an aversive shock procedure were taken immediately post-shock, both while subjects were sober and after they had consumed one of the four alcohol doses. High risk men were found to rate the experience of the shock as more uncomfortable and painful overall than the low risk controls. Pharmacologically significant levels of alcohol were found to reduce or eliminate these group differences, suggesting that alcohol has a "normalizing" effect on pain and discomfort perceptions in high risk men. Only the higher doses of alcohol were found significantly to dampen subjects' shock rating scores. High risk males' increased sensitivity to pain and discomfort, combined with the negatively reinforcing effects of reducing these perceptions at moderate to high alcohol doses, may play a role in predisposing high risk males for the development of alcoholism.

Adolescent↗
PubMed1993

Heart-rate reactivity and alcohol consumption among sons of male alcoholics and sons of non-alcoholics.

Recent studies have demonstrated that sons of male alcoholics with multigenerational family histories of male alcoholism are characterized by sober heart-rate hyperreactivity to aversive stimuli, susceptibility to alcohol-induced dampening of that hyperreactivity and by increased resting heart rate while intoxicated. Regression analyses indicate that the magnitude of alcohol-induced change in resting and reactive cardiac response is significantly and powerfully associated with the degree of self-reported voluntary alcohol consumption among 85 non-alcoholic males who are either lacking or who have moderate or extensive family histories of male alcoholism. It appears that heightened sensitivity to alcohol-induced increase in resting and decrease in reactive heart rate might mark or underlie familial risk for developing alcoholism.

Adolescent↗
PubMed1992

Event-related potential sensitivity to acoustic and semantic properties of terminal words in sentences.

This experiment was concerned with the effects of phonologically correct masking on the electrophysiological responses to terminal words of spoken sentences differing in contextual constraint. Two event-related potential (ERP) components, the N400 and N200, were recorded to the terminal words of high and low constraint sentences in four conditions. In the Control condition, subjects (Ss) simply attended to the sentences with no explicit task instructions. In the Semantic condition, Ss were required to listen to the stimuli in order to make semantic judgements about the terminal word of each sentence. The Control+Masking condition was identical to the Control condition except for the simultaneous presentation of a masking stimulus. The Semantic+Masking condition had Ss listening to sentences in the presence of masking with the task of making semantic judgements about the terminal word of each sentence. ERPs were recorded from Fz, Cz, Pz, T3, and T4 in 10 subjects. Amplitudes of both the N200 and the N400 were sensitive to contextual constraint with larger responses elicited by the terminal words of low constraint sentences. In addition to demonstrating the co-occurrence of the N200 and N400, this experiment highlighted a functional separation between the two components. Masking had no statistically significant effect on N200 latency but N400 latency was delayed in the masked conditions relative to those in the unmasked conditions. It is proposed that the N200 and N400 are manifestations of two different processes; the N200 reflects the acoustic/phonological processing of the terminal word while the N400 reflects the cognitive/linguistic processing. The relationship between the N200 recorded in this experiment and the discrimination N200 is discussed.

Adolescent↗
PubMed1992

The effects of alcohol on the cardiovascular stress response in men at high risk for alcoholism: a dose response study.

Men at risk for alcoholism appear to be cardiovascularly hyperreactive to stressors; high doses of alcohol have been found to significantly dampen this hyperreactivity. The present study examined the effects of various doses of alcohol on cardiovascular reactivity in high- versus low-risk men. Cardiovascular reactivity to a stressor (unavoidable shock) was examined in men with multigenerational family histories of alcoholism and in family history negative men while they were sober and after they had consumed one of five alcohol doses (active placebo, 0.50, 0.75, 1.00 or 1.32 ml 95% USP alcohol/kg body weight). No significant placebo effects were observed in the active placebo condition. Furthermore, the cardiovascular reactivity dampening effect in high-risk men was evident only at moderate to high doses of alcohol, suggesting that men at high risk for the development of alcoholism must consume moderately high doses of alcohol in order to obtain this potentially reinforcing consequence.

Adolescent↗
PubMed1990

The effects of processing requirements on neurophysiological responses to spoken sentences.

Ten English speaking subjects listened to sentences that varied in sentential constraint (i.e., the degree to which the context of a sentence predicts the final word of that sentence) and event-related potentials (ERPs) were recorded during the presentation of the final word of each sentence. In the Control condition subjects merely listened to the sentences. In the Orthographic processing condition subjects merely listened to the sentences. In the Orthographic processing condition subjects decided, following each sentence, whether a given letter had been present in the final word of the preceding sentence. In the Phonological processing condition the subjects judged whether a given speech sound was contained in the terminal word. In the Semantic processing condition subjects determined whether the final word was a member of a given semantic category. A previous finding in the visual modality that the N400 component was larger in amplitude for low constraint sentence terminations than for high was extended to the auditory modality. It was also found that the amplitude of a N200-like response was similarly responsive to contextual constraint. The hypothesis that N400 amplitude would vary significantly with the depth of processing of the terminal word was not supported by the data. The "N200" recorded in this language processing context showed the classic frontocentral distribution of the N200. The N400 to spoken sentences had a central/centroparietal distribution similar to the N400 in visual modality experiments. It is suggested that the N400 obtained in these sentence contexts reflects an automatic semantic processing of words that occurs even when semantic analysis is not required to complete a given task. The cooccurrence and topographical dissimilarity of the "N200" and N400 suggest that the N400 may not be a delayed or a generic N200.

Adolescent↗
PubMedDate not supplied

Examination of the short form of the Inventory of Drinking Situations (IDS-42) in a young adult university student sample.

The 42-item version of the Inventory of Drinking Situations (IDS-42) assesses relative frequency of drinking behavior across eight categories of drinking situations and was originally developed as a method for identifying high-risk situations in alcoholic samples. This study was designed to examine the psychometric properties of the IDS-42 in a sample of university students in order to assess its suitability as an assessment tool in the non-clinical population. Three hundred and ninety-six students (111 M, 283 F, 2 with missing gender data) completed the IDS-42 and a well established measure of drinking motives, the Drinking Motives Questionnaire (DMQ). Confirmatory factor analysis of the IDS-42 established a hierarchical factor structure with eight lower-order factors and three higher-order factors of negatively-reinforcing situations, positively-reinforcing situations, and temptation situations. The eight lower-order IDS-42 factors demonstrated moderate to high internal consistency and excellent concurrent validity with conceptually-similar DMQ subscale scores. Non-parametric analyses revealed that male students reported a higher drinking frequency overall as compared to female students, particularly in IDS-42 situations involving Social Pressure to Drink, Pleasant Times with Others, Testing Personal Control, and Urges and Temptations. Across the entire sample of university student drinkers, a higher drinking frequency was reported in positively-reinforcing situations as compared to negatively-reinforcing situations and temptation situations, as predicted. Results suggest the IDS-42 possesses good psychometric properties and support its utility as a tool in identifying situation-specific antecedents to drinking among university students.

Adolescent↗
PubMedDate not supplied

The context-specific positive alcohol outcome expectancies of university women.

Alcohol outcome expectancies are subjective beliefs about the psychological and physical effects of alcohol consumption. The primary purpose of the present study was to determine whether the types and strengths of university women's positive alcohol outcome expectancies differ across three typical student drinking contexts. Seventy-eight female undergraduates completed three versions of the Expectancy Context Questionnaire (ECQ) depicting Social, Sexual, and Tension drinking contexts, respectively, and then prospectively self-monitored their own drinking behavior. Respondent's total positive expectancies were strongest, overall, in the Sexual context and weakest in the Tension context. Consistent with hypothesis, the strengths of certain specific alcohol expectancies varied significantly across contexts: Arousal expectancies were strongest in the Sexual context and weakest in the Social context; Social/Sexual Enhancement expectancies were strongest in the Sexual context and weakest in the Tension context; and Global Positive Affect expectancies were strongest in the Social context and weakest in the Tension context. Drinking levels over the week of self-monitoring were significantly predicted by Global Positive Affect and Relaxation expectancies in the Social Context, and by Social/ Sexual Enhancement, Arousal, and Relaxation expectancies in the Sexual Context. The theoretical and clinical importance of identifying drinking context when examining alcohol expectancies is discussed.

Adolescent↗