Inhibitory Performance in Smokers Relative to Nonsmokers When Exposed to Neutral, Smoking- and Money-Related Pictures

Introduction: Smoking is associated with significant negative health consequences. It has been suggested that deficient inhibitory control may be implicated in (nicotine) addiction, but its exact role has not yet been elucidated. In the current study, our aim was to investigate the role of inhibitory control in relation to nicotine addiction in contexts that differ in terms of reward. Methods: Participants filled out questionnaires and performed a go/no-go task with three conditions. In one condition, the stimuli were neutral color squares, and in the reward conditions, these were smoking-related pictures and money-related pictures, respectively. In total, 43 non-abstinent individuals that smoke and 35 individuals that do not smoke were included in the sample. Results: The main results showed that individuals that smoke, relative to individuals that do not smoke, had reduced inhibitory control in both reward contexts, relative to a neutral context. The reductions in inhibitory control were mirrored by speeded responses. Conclusions: Individuals that smoke seem to present with reduced inhibitory control, which is most pronounced in contexts of reward. Consistent with incentive sensitization theory, the reduced inhibitory control may be (at least partly) due to the heightened approach bias to reward-related stimuli as indicated by the speeded responses.

Exploring the factors of excessive smartphone use by undergraduate students

There is an exponential increase of apprehension in the uptake, affordances and the excessive use of smartphones by multiple categories of users and the impact on the society. The research evaluates excessive use within a user community in a developing country landscape. It is estimated that many young people spend too much time on their phones and the projections suggest even higher numbers with disturbing estimations. The unravelling of contexts surrounding the excessive use of digital devices such as smartphones and the elements that lead to it are mostly unexplored. Consequently, the study illuminated the fundamental mechanisms that influence excessive use of smartphones by learners using perspectives from the Incentive-sensitization Theory (IST) to add scope and breadth. A total of 110 undergraduate students participated in the study. The fundamental results showed that the increase in the volume of activities such as online games, virtual world games and social media was responsible for excessive use. The findings provided an understanding of the relationship between depression-like behaviour and anxiety and shed new light on the influence of excessive use, smartphone stress and depression-related symptoms on students. The study outlined the implications of the results for prevention and regulation.

Mechanisms of Alcohol Addiction: Bridging Human and Animal Studies

Aim The purpose of this brief narrative review is to address the complexities and benefits of extending animal alcohol addiction research to the human domain, emphasizing Allostasis and Incentive Sensitization, two models that inform many pre-clinical and clinical studies. Methods The work reviewed includes a range of approaches, including: a) animal and human studies that target the biology of craving and compulsive consumption; b) human investigations that utilize alcohol self-administration and alcohol challenge paradigms, in some cases across 10 years; c) questionnaires that document changes in the positive and negative reinforcing effects of alcohol with increasing severity of addiction; and d) genomic structural equation modeling based on data from animal and human studies. Results Several general themes emerge from specific study findings. First, positive reinforcement is characteristic of early stage addiction and sometimes diminishes with increasing severity, consistent with both Allostasis and Incentive Sensitization. Second, evidence is less consistent for the predominance of negative reinforcement in later stages of addiction, a key tenant of Allostasis. Finally, there are important individual differences in motivation to drink at a given point in time as well as person-specific change patterns across time. Conclusions Key constructs of addiction, like stage and reinforcement, are by necessity operationalized differently in animal and human studies. Similarly, testing the validity of addiction models requires different strategies by the two research domains. Although such differences are challenging, they are not insurmountable, and there is much to be gained in understanding and treating addiction by combining pre-clinical and clinical approaches.

Dissociation between wanting and liking for coffee in heavy drinkers

Background: There is an ongoing discussion about the addictive strength of caffeine. According to the incentive-sensitization theory, the development and the maintenance of drug addiction is the result of a selective sensitization of brain regions that are relevant for wanting without a corresponding increase in liking. Dissociations of wanting and liking have been observed with a wide range of drugs in animals. For human subjects, results are inconclusive, which is possibly due to invalid operationalizations of wanting and liking. Aim: The present study examined dissociations of wanting and liking for coffee in heavy and low/non-consumers with newly developed and validated response time-based assessment procedures for wanting and liking. Methods: For this study 24 heavy and 32 low/non-consumers of coffee completed two versions of the Implicit-Association Test (IAT), one of which has been developed and validated recently to assess wanting for coffee, whereas the other reflects an indicator of liking for coffee. Results: Results revealed a significant interaction between group (heavy vs. low/non-consumers) and IAT type ( wanting vs. liking) indicating that heavy coffee drinkers differed from low/non-consumers by displaying increased wanting but not liking for coffee. Interpretation: These data confirm that heavy coffee consumption is associated with strong wanting despite low liking for coffee, indicating that wanting becomes independent from liking through repeated consumption of caffeine. This dissociation provides a possible explanation for the widespread and stable consumption of caffeine-containing beverages.

Intermittent access cocaine self-administration produces psychomotor sensitization: effects of withdrawal, sex and cross-sensitization

The psychomotor activating effects of drugs such as cocaine or amphetamine can change in very different ways – showing sensitization or tolerance – depending on whether they are administered more or less intermittently. This behavioral plasticity is thought to reflect, at least in part, changes in dopamine (DA) neurotransmission, and therefore, may provide insights into how repeated drug use promotes the development of substance use disorders. Indeed, the most widely used preclinical model of cocaine addiction, which involves Long Access (LgA) self-administration procedures, is reported to produce tolerance to cocaine’s psychomotor activating effects and effects on DA activity. This is cited as evidence in support of the view that in addiction, drug-seeking and-taking is motivated to overcome this DA deficiency and associated anhedonia. In contrast, Intermittent Access (IntA) cocaine self-administration is more effective than LgA in producing addiction-like behavior, but sensitizes DA neurotransmission. There is, however, very little information concerning the effects of IntA experience on the psychomotor activating effects of cocaine. The purpose of the studies reported here, therefore, was to determine whether IntA experience produces psychomotor sensitization with similar characteristics to that produced by the intermittent, noncontingent administration of cocaine. It did. The psychomotor sensitization produced by IntA experience with cocaine: (1) was greater after a long (30 days) vs short (1 day) period of withdrawal; (2) was greater in females than males; and (3) resulted in cross-sensitization to another psychomotor stimulant drug, amphetamine. This pattern of cocaine experience-dependent plasticity favors an incentive-sensitization view of addiction.

Low sensitivity to, and craving for, alcohol in naturalistic and laboratory settings

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Low sensitivity to alcohol is a well-established risk factor for the development of an alcohol use disorder. This risk is transmitted along several routes included, but not limited to, differences in alcohol expectancies, association with heavier drinking peers, and differences in motivations for drinking. A recent line of inquiry drawing on the Incentive Sensitization Theory of Addiction has emerged as another potential factor through which alcohol sensitivity interfaces with alcohol use disorder. The Incentive Sensitization Theory of Addiction posits that formerly neutral cues become imbued with incentive salience through their repeated pairing with drug use and become highly sought after in their own right. Psychophysiological laboratory work has produced promising results that suggest that this process is stronger for low sensitivity drinkers relative to their higher sensitivity peers. The present work attempts to extend these laboratory results into drinkers' natural environment. Participants completed a 10-day period of Ecological Momentary Assessment where they reported on their exposure to cues for alcohol use, levels of craving for alcohol, and their use of alcohol. Results indicated that lower sensitivity drinkers were exposed to alcohol cues more frequently, were more likely to drink, and to drink more heavily when drinking. Cue exposure was a robust predictor of momentary craving, which in turn was a predictor of the likelihood of drinking and marginally associated with the heaviness of drinking. Contrary to hypotheses, alcohol sensitivity was not a moderator of any associations between cue exposure and drinking or craving and drinking. Despite the lack of the expected moderating effects of alcohol sensitivity, the results indicate that craving is a substantial predictor for drinking behavior in an at-risk population. This association between craving and drinking in the "real world" in a non-clinical population has only been rarely documented previously and presents an exciting avenue for continued research.