3 research outputs found
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Effects of stress on emotional reactivity in hostile heavy social drinkers following dietary tryptophan enhancement
Aim: Because individuals high on hostility may be at risk for alcohol abuse due to serotonergic dysfunction and greater reactivity to stress, we examined the effects of acute dietary tryptophan enhancement and stress on mood and craving for alcohol in low-hostile (LoH) and high-hostile (HiH) individuals. Methods: Thirty-four LoH and 33 HiH heavy social drinkers [selection based on the Hostility scale from the Buss and Perry Aggression Questionnaire (1992)] received either tryptophan-enriched or control diet and underwent a stress-induction procedure. Trait differences between the two hostile groups were explored using personality, anxiety, and depression questionnaires. Mood, craving for alcohol, and salivary cortisol levels (CORT) were measured before and after tryptophan and after stress-induction. Heart rate (HR) was measured during stress-induction. Results: HiHs compared to LoHs scored higher on the depression and anxiety trait scales as well in the character dimension Harm Avoidance and reported more of stress exposure over the past month. They also showed more negative mood and higher craving for alcohol. Diet alone did not produce any subjective or physiological effects. Stress increased CORT, HR, negative mood, and craving for alcohol. HiHs displayed higher CORT increase and lower cardiovascular reactivity in response to stress compared to LoHs. Opposite to the predictions, tryptophan enhancement selectively facilitated stress-induced increase in craving in the HiHs. Conclusion: Among heavy drinkers HiHs report higher craving for alcohol and show greater reactivity to stress as measured by CORT and negative mood. The effects of stress on craving in HiHs may be mediated by a serotonergic mechanism
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Degree of dependence influences the effect of smoking on cognitive flexibility.
Pre-frontal cortical (PFC) dysfunction has been put forward as the basis for development and maintenance of addiction. To explore this relationship, the present study investigated the effects of smoking on PFC-mediated cognitive flexibility and subjective states in low- (LD) and high-dependent (HD) smokers. Twenty-four LD and 24 HD smokers (Fagerström dependence scores = 4 and = 5, respectively) were randomly allocated to non-smoking or smoking condition (12 LD and 12 HD participants per condition). After abstaining from smoking for a minimum of two hours volunteers completed a battery of questionnaires [nicotine-specific Visual Analogue Scales (Nic-VAS), Questionnaire of Smoking Urges (QSU) and Profile of Mood States (POMS)] at baseline [T1] and again after smoking one cigarette or remaining abstinent [T2]. Cognitive flexibility was evaluated at T2 using the Intra-Extra Dimensional Set-Shift test. The Rapid Visual Information Processing test was performed as a control nicotine-sensitive task at several time points during the experiment. Compared to LD smokers, HD smokers had higher salivary cotinine and breath CO levels at baseline and reported more craving (QSU) and felt less stimulated (Nic-VAS), vigorous, friendly and elated (POMS) throughout the experiment. Smoking increased Nic-VAS ratings of 'Buzzed' and 'Dizzy' and decreased craving in all participants. Smoking selectively impaired cognitive flexibility in HD smokers since HD smokers allocated to the smoking condition made significantly more errors with the intra-dimensional set-shift than their counterparts in the abstinent condition. No effect of smoking on RVIP test was observed, most likely due to the practice effect which was significant in both groups of smokers. The practice effect, however, was more pronounced in LD smokers. This study demonstrates that PFC-mediated cognitive effects of smoking as well as subjective reports vary according to the degree of nicotine dependence
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A role for glutamate in subjective response to smoking and its action on inhibitory control
Rationale Our previous study using memantine in smokers suggests that there may be a differential role for N-methyl-d-aspartate (NMDA) receptors in the subjective and cognitive effects of smoking. Objectives This study was designed to investigate if d-cycloserine (DCS) would modulate the subjective and cognitive effects of limited smoking. Methods Forty-eight habitual smokers abstinent for a minimum of 2 h were randomly allocated to receive either placebo or 50 mg DCS (double-blind) and were subsequently required either to smoke half of one cigarette or to remain abstinent. Subjective and physiological effects of DCS were measured at baseline, 90 min postcapsule, and again after the partial-smoking manipulation, while the effects on sustained attention (rapid visual information processing test—RVIP) and cognitive flexibility (intra–extra dimensional set-shift test—IED) were evaluated only after the partial-smoking manipulation. Results DCS alone did not produce significant subjective effects other than an increase in ratings of “Stimulated”. In combination with partial smoking, however, DCS blocked the smoking-induced increase in “Stimulated” and the decrease in “Relaxed” ratings. Furthermore, in combination with smoking, DCS reduced the number of false alarms during the RVIP test (an index of inhibitory control) and produced a small increase in diastolic blood pressure. DCS failed to modulate IED performance. Conclusions These findings provide further evidence of a role for glutamate release in the subjective effects of smoking but not the effects on attention and cognitive flexibility. Furthermore, our results indicate that glutamate release may also be involved in the effect of smoking on inhibitory control