Alcohol choice and amphetamine effects in light and moderate drinkers

The amphetamine response moderates the relationship between negative emotionality and alcohol use

BACKGROUND

Considerable evidence suggests that sensitivity to the stimulant effects of alcohol and other drugs is a risk marker for heavy or problematic use of those substances. A separate body of research implicates negative emotionality. The goal of the present study was to evaluate the independent and interactive effects of the stimulant response, assessed with an amphetamine challenge, and negative emotionality on alcohol and drug use.

METHODS

Healthy young women and men completed the Multidimensional Personality Questionnaire (MPQ) and an inventory assessing alcohol and other drug use. Subsequently, the effects of 10-mg d-amphetamine were determined in the laboratory using the Stimulant scale of the Biphasic Alcohol Effects Scale. Hierarchical regression analyses evaluated the effects of amphetamine response and the MPQ factor Negative Emotionality on measures of substance use.

RESULTS

The amphetamine response moderated relationships between negative emotionality and alcohol use: in combination with a robust amphetamine response (i.e., enhanced stimulant effects as compared with baseline), negative emotionality predicted greater alcohol consumption, more episodes of binge drinking, and more frequent intoxication in regression models. A strong stimulant response independently predicted having used an illicit drug, and there was a trend for it to predict having used alcohol. Negative emotionality alone was not associated with any measure of alcohol or drug use.

CONCLUSIONS

Consistent with the idea that emotion-based behavioral dysregulation promotes reward seeking, a high level of negative emotionality was associated with maladaptive alcohol use when it co-occurred with sensitivity to drug-based reward. The findings contribute to our understanding of how differences in personality may interact with those in drug response to affect alcohol use.

Response to alcohol in women: role of the menstrual cycle and a family history of alcoholism

The present study determined whether: (1) the response to alcohol varied as a function of menstrual cycle phase and (2) women with a paternal history of alcoholism (FHP) were less sensitive to the effects of alcohol compared to women without a family history of alcoholism (FHN). The behavioral effects of alcohol (0.00, 0.25, and 0.75 g/kg) were evaluated in 21 FHN and 24 FHP women; each dose was tested during both the midfollicular and late luteal phases of the menstrual cycle. Baseline negative mood was increased during the luteal phase compared to the follicular phase (increased Beck Depression scores and decreased Vigor, Arousal, and Friendly scores). Alcohol increased ratings of Drug Liking and Good Drug Effect more in the luteal phase than the follicular phase. FHP women had greater negative mood during the luteal phase and some of these dysphoric effects were increased by alcohol more in FHP women than FHN women. Alcohol impaired performance, with no group or menstrual cycle differences. However, consistent with previous studies, FHP women were less impaired by alcohol than FHN women on the balance task. These data indicate that (1) the differences in response to alcohol across the menstrual cycle are subtle, although alcohol is liked more during the luteal phase; (2) increases in dysphoric mood during the luteal phase are more pronounced in FHP women compared to FHN women, particularly after alcohol; and (3) the differences observed in response to alcohol between FHP and FHN women are less pronounced than previously shown in men.

Amphetamine self-administration in light and moderate drinkers

BACKGROUND

Light and moderate drinkers respond differently to the effects of abused drugs, including stimulants such as amphetamine. The purpose of this study was to determine whether light and moderate drinkers differ in their sensitivity to the reinforcing and subjective effects of d-amphetamine. We hypothesized that moderate drinkers (i.e., participants that reported consuming at least seven alcohol-containing beverages per week) would be more sensitive to the reinforcing and positive subject-rated effects of d-amphetamine than light drinkers.

METHODS

Data from four studies that employed similar d-amphetamine self-administration procedures and subject-rated drug-effect measures were included in the analysis. Light (n = 17) and moderate (n = 16) drinkers sampled placebo, low (8 to 10 mg), and high (16 to 20 mg) doses of oral d-amphetamine administered in eight capsules. Following sampling sessions, participants worked for a maximum of eight capsules, each containing 12.5% of the previously sampled dose, on a modified progressive-ratio schedule of reinforcement.

RESULTS

Both active doses of d-amphetamine functioned as a reinforcer in the moderate drinkers, while only the high dose did so in the light drinkers. The moderate drinkers worked for significantly more capsules that contained the high dose of d-amphetamine than did the light drinkers. d-Amphetamine produced prototypical stimulant-like subjective effects (e.g., dose-dependent increases in ratings of Good Effects; Like Drug and Willing to Take Again). Moderate drinkers reported significantly greater subjective effects than the light drinkers.

CONCLUSION

These results are consistent with those from previous laboratory experiments and suggest that moderate alcohol consumption may increase vulnerability to the abuse-related effects of stimulants.

Psychopharmacological effects of oxycodone in healthy volunteers: roles of alcohol-drinking status and sex

BACKGROUND

Studies have shown that alcohol-drinking status modulates psychopharmacological effects of several drugs. We sought to determine if drinking status modulates the effects of a prescription opioid, oxycodone, in healthy volunteers. We included sex of the volunteer in the statistical analyses since this is a factor that is known to alter several pharmacodynamic effects of opioids in nonhumans and humans.

METHODS

Fifteen light drinkers (eight males) and 14 moderate drinkers (eight males) participated in a crossover, randomized, double-blind study in which they received 0, 10, and 20mg of oxycodone (p.o.). Dependent measures were subjective, psychomotor/cognitive, reinforcing, and physiological effects.

RESULTS

Self-reported alcohol-drinking status did not modulate the effects of oxycodone. However, there were a number of Sex x Dose interactions with females reporting more and larger unpleasant effects than males (e.g., visual analog scale ratings of "nauseated" greater in females than in males).

CONCLUSIONS

Studies have established that moderate drinkers report a greater degree of abuse liability-related effects than do light drinkers with several different drugs, including diazepam, amphetamine, and nitrous oxide, but we were unable to establish this with the prescription opioid, oxycodone. However, we did observe sex differences in several subjective effects of oxycodone, a finding that is consistent with the extant literature showing sex differences in pharmacodynamic effects of opioids.

A possible link between sensation-seeking status and positive subjective effects of oxycodone in healthy volunteers

Sensation-seeking is a personality trait that is linked to use and abuse of drugs. Laboratory studies have established that high sensation seekers, as measured by different instruments, are more likely to report abuse liability-related subjective effects from drugs such as nicotine, alcohol, and d-amphetamine than low sensation seekers. One class of drugs that has not been studied to date in this fashion is opioids. Accordingly, a retrospective analysis encompassing five studies that examined oxycodone effects, including its abuse liability-related effects, was conducted in subjects categorized as high or low sensation seekers. In addition, because there appear to be sex differences in how males and females respond to opioids, this factor was taken into account in the analysis. Seventy one subjects who scored on the lower end (15 and 19 low sensation-seeking males and females, respectively) or the higher end (23 and 14 high sensation-seeking males and females) of the Disinhibition subscale of the Sensation-Seeking Scale-Form V were studied for their responses to 0, 10, and 20mg of oral oxycodone. Ratings of "pleasant bodily sensations" were significantly higher after oxycodone administration than placebo only in male and female high sensation seekers. Ratings of "take again," "drug liking," "carefree," and "elated (very happy)" also tended to differentiate high from low sensation seekers although Group x Dose interactions were only marginally significant with the latter three ratings. Male and female low sensation seekers and female high sensation seekers reported dysphoric effects (e.g., ratings of nauseated) particularly after administration of the 20mg oxycodone dose. The results of this analysis provide suggestive evidence that high sensation seekers are more likely to experience greater positive subjective effects from oxycodone than low sensation seekers, but likelihood of experiencing negative effects is more complex (involving both sensation-seeking status and sex).

Choice of nitrous oxide and its subjective effects in light and moderate drinkers

BACKGROUND

Alcohol-drinking status has been shown to modulate the reinforcing and subjective effects of a number of drugs. We have previously published two studies on the modulating effects of alcohol-drinking status on choice for, and subjective effects of, nitrous oxide, but the results were equivocal. Using a methodology different from our previous studies, we sought to determine in a more definitive fashion the degree to which the choice of nitrous oxide and its subjective effects were modulated by drinking status.

METHODS

Four concentrations of nitrous oxide (0, 20, 30, and 40%) were administered to 16 moderate drinkers (MDs) and 16 light drinkers (LDs) across four 3.5-h sessions. During experimental sessions, subjects first completed two 10-min sampling trials in which one of the nitrous oxide concentrations and placebo (100% oxygen) were inhaled. Subjective and psychomotor tests were given 5min into each sampling trial. During the subsequent choice period, subjects were allowed to choose what they wanted to inhale (drug, placebo, or "drug-free air") on nine contiguous 5-min choice trials.

RESULTS

Choice of nitrous oxide was modulated by drinking status: MDs but not LDs chose nitrous oxide significantly more times than placebo, and MDs also chose nitrous oxide significantly more times than did LDs. At each active nitrous oxide concentration, MDs reported more abuse liability-related subjective effects, especially at the 20% and 30% concentrations.

CONCLUSIONS

The results of the present study provide more conclusive evidence that choice as well as subjective effects of nitrous oxide is modulated by alcohol-drinking status.

Choice of sevoflurane and its subjective and psychomotor effects in light and moderate drinkers

BACKGROUND

Sevoflurane, an inhalant of the volatile anesthetic class, has neurobiological and behavioral effects in common with abused inhalants and ethanol. We sought to determine if choice for subanesthetic doses of sevoflurane, and its subjective and psychomotor effects, would differ as a function of alcohol-drinking status in healthy volunteers.

METHODS

The effects of four concentrations of sevoflurane (0, 0.2, 0.4, 0.8% sevoflurane in oxygen) were studied in 16 light drinkers and 16 moderate drinkers. During each of four sessions, subjects sampled a concentration of sevoflurane and 100% O(2) (placebo) for 10 min each. Subjective and psychomotor testing commenced 5 min into each sampling trial. Later, within the session, subjects chose nine times, once every 5 min, among sevoflurane (e.g., "Agent A"), placebo (e.g., "Agent B," 100% O(2)), or neither (and were administered 100% O(2), identified as "drug-free air").

RESULTS

Choice for sevoflurane at the 0.4% concentration was significantly higher in the moderate drinkers than in the light drinkers. A number of subjective effects reported during inhalation of sevoflurane were markedly lower in the moderate-drinking group than in the light-drinking group. However, psychomotor impairment induced by sevoflurane was similar in magnitude in both groups.

CONCLUSIONS

Alcohol-drinking status affected sevoflurane choice. The results are consistent with several studies comparing light and heavier drinkers, using other drugs. Although both drinking groups were similarly impaired by sevoflurane, the moderate drinkers reported less of a subjective response than light drinkers, suggestive of cross-tolerance.

The reinforcing, subject-rated, performance, and cardiovascular effects of d-amphetamine: influence of sensation-seeking status

Individual differences that may contribute to vulnerability to abuse drugs have been identified. Sensation-seeking status has been shown to influence both vulnerability to drug use and response to acute drug administration. The purpose of the present experiment was to examine the reinforcing effects of d-amphetamine in high and low sensation-seeking subjects using a modified progressive-ratio procedure. A battery of subject-rated, performance, and cardiovascular measures was also included to better characterize the effects of d-amphetamine in these groups. Ten high sensation seekers and ten low sensation seekers that were matched for education, age, drug use, height, and weight, first sampled doses of d-amphetamine (0, 8, and 16 mg). In subsequent sessions, subjects were offered the opportunity to work for the sampled dose on a modified progressive-ratio procedure. d-Amphetamine functioned as a reinforcer and produced prototypical stimulant-like effects (e.g., increased subject-ratings of Like Drug, enhanced performance, and increased heart rate). High sensation seekers were more sensitive than low sensation seekers to the reinforcing and some of the subject-rated effects of d-amphetamine. The results of the present experiment extend those of previous findings by demonstrating that the reinforcing effects of d-amphetamine vary as a function of the biologically based sensation-seeking personality trait. These results suggest that increased stimulant drug use and abuse among high sensation seekers may be related, in part, to increased sensitivity to the reinforcing effects of stimulants among these individuals.

Alprazolam attenuates the behavioral effects of d-amphetamine in humans

The results of preclinical behavioral pharmacology studies suggest that gamma-aminobutyric acidA (GABAA) receptor modulators attenuate the behavioral effects of commonly abused stimulants such as amphetamines and cocaine under a variety of behavioral arrangements including drug discrimination and self-administration. In the present experiment, 6 healthy humans learned to discriminate 15-mg oral D-amphetamine. After acquiring the discrimination (ie, . > or = 80% correct responding on 4 consecutive days), the effects of a range of doses of D-amphetamine (0, 2.5, 5, 10, and 15 mg), alone and following pretreatment with alprazolam (0 and 0.5 mg), a GABAA receptor modulator, were assessed. D-Amphetamine alone functioned as a discriminative stimulus and produced stimulant-like self-reported drug effects (eg, increased scores on a Stimulant-Sensitive Adjective-Rating Scale). These effects were generally a function of dose. Alprazolam alone did not occasion D-amphetamine-like discriminative stimulus effects, nor did it increase ratings of sedation or impair performance. Alprazolam pretreatment significantly attenuated the discriminative stimulus effects of D-amphetamine, and some of the self-reported drug effects. Future human laboratory experiments should compare the behavioral effects of D-amphetamine alone and following pretreatment with alprazolam using other behavioral arrangements such as drug self-administration. Future laboratory experiments with humans should also determine if benzodiazepines with lower abuse potential (eg, oxazepam) might also attenuate the behavioral effects of D-amphetamine.