The loss of control over drug intake that occurs in addiction was initially believed to result from disruption of subcortical reward circuits. However, imaging studies in addictive behaviours have identified a key involvement of the prefrontal cortex (PFC) both through its regulation of limbic reward regions and its involvement in higher-order executive function (for example, self-control, salience attribution and awareness). This Review focuses on functional neuroimaging studies conducted in the past decade that have expanded our understanding of the involvement of the PFC in drug addiction. Disruption of the PFC in addiction underlies not only compulsive drug taking but also accounts for the disadvantageous behaviours that are associated with addiction and the erosion of free will.

Dysfunction of the prefrontal cortex in addiction: neuroimaging findings and clinical implications

Context Although young adulthood is often characterized by rapid intellectual and social development, college-aged individuals are also commonly exposed to circumstances that place them at risk for psychiatric disorders. Objectives To assess the 12-month prevalence of psychiatric disorders, sociodemographic correlates, and rates of treatment among individuals attending college and their non–college-attending peers in the United States. Design, Setting, and Participants Face-to-face interviews were conducted in the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (N = 43 093). Analyses were done for the subsample of college-aged individuals, defined as those aged 19 to 25 years who were both attending (n = 2188) and not attending (n = 2904) college in the previous year. Main Outcome Measures Sociodemographic correlates and prevalence of 12-month DSM-IV psychiatric disorders, substance use, and treatment seeking among college-attending individuals and their non–college-attending peers. Results Almost half of college-aged individuals had a psychiatric disorder in the past year. The overall rate of psychiatric disorders was not different between college-attending individuals and their non–college-attending peers. The unadjusted risk of alcohol use disorders was significantly greater for college students than for their non–college-attending peers (odds ratio = 1.25; 95% confidence interval, 1.04-1.50), although not after adjusting for background sociodemographic characteristics (adjusted odds ratio = 1.19; 95% confidence interval, 0.98-1.44). College students were significantly less likely (unadjusted and adjusted) to have a diagnosis of drug use disorder or nicotine dependence or to have used tobacco than their non–college-attending peers. Bipolar disorder was less common in individuals attending college. College students were significantly less likely to receive past-year treatment for alcohol or drug use disorders than their non–college-attending peers. Conclusions Psychiatric disorders, particularly alcohol use disorders, are common in the college-aged population. Although treatment rates varied across disorders, overall fewer than 25% of individuals with a mental disorder sought treatment in the year prior to the survey. These findings underscore the importance of treatment and prevention interventions among college-aged individuals.

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Mental health of college students and their non-college-attending peers: results from the National Epidemiologic Study on Alcohol and Related Conditions.

Music, an abstract stimulus, can arouse feelings of euphoria and craving, similar to tangible rewards that involve the striatal dopaminergic system. Using the neurochemical specificity of [(11)C]raclopride positron emission tomography scanning, combined with psychophysiological measures of autonomic nervous system activity, we found endogenous dopamine release in the striatum at peak emotional arousal during music listening. To examine the time course of dopamine release, we used functional magnetic resonance imaging with the same stimuli and listeners, and found a functional dissociation: the caudate was more involved during the anticipation and the nucleus accumbens was more involved during the experience of peak emotional responses to music. These results indicate that intense pleasure in response to music can lead to dopamine release in the striatal system. Notably, the anticipation of an abstract reward can result in dopamine release in an anatomical pathway distinct from that associated with the peak pleasure itself. Our results help to explain why music is of such high value across all human societies.

Anatomically distinct dopamine release during anticipation and experience of peak emotion to music

Impulsivity as a vulnerability marker for substance-use disorders: Review of findings from high-risk research, problem gamblers and genetic association studies

Attentional bias in addictive behaviors: A review of its development, causes, and consequences

Effects of expectancy and abstinence on the neural response to smoking cues in cigarette smokers: an fMRI study

Simultaneous polysubstance use (SPU) is a common phenomenon, yet little is known about how various substances are used with one another. In the present study 149 drug-using university students completed structured interviews about their use of various substances. For each substance ever used, participants provided details about the type, order and amount of all substances co-administered during its most recent administration. Alcohol, tobacco and cannabis were frequently co-administered with each other and with all other substances. Chi-squared tests revealed that when alcohol was used in combination with any of cannabis, psilocybin, MDMA, cocaine, amphetamine, methylphenidate (ps < 0.01) or LSD (p < 0.05) its initial use preceded the administration of the other substance. Paired samples t-tests revealed that when alcohol was used with cocaine (p < 0.01) or methylphenidate (p < 0.05) it was ingested in greater quantities than when used in their absence. Patterns of cannabis use were not systematically related to other substances administered. Finally, using one-sample t-tests, tobacco use was demonstrated to be increased relative to ‘sober’ smoking rates when used with alcohol, cannabis, psilocybin, MDMA, cocaine, amphetamine (ps < 0.001), LSD (p < 0.01) or methylphenidate (p < 0.05). Results suggest that many substances are routinely used in a SPU context and that the pattern in which a substance is used may be related to other substances co-administered. Copyright © 2006 John Wiley & Sons, Ltd.

Patterns of simultaneous polysubstance use in drug using university students

Objective:Methylphenidate (MPH) is a prescription stimulant drug with known abuse potential; however, little is known about its patterns of misuse or the characteristics of its abusers.Methods:A sa...

https://journals.sagepub.com/doi/pdf/10.1177/070674370505000805

Characteristics of methylphenidate misuse in a university student sample.

Nicotine Increases Alcohol Self-Administration in Non-Dependent Male Smokers

Positron emission tomography and [11C]raclopride were used to assess the dopaminergic response to cigarette smoking in ten smokers. Nicotine-deprived smokers were scanned twice on separate days. In one condition, participants smoked their usual brand of cigarettes while in the scanner and in the other condition they remained nicotine abstinent. On each day, subjects monitored the hedonic properties of their experience as well as their levels of craving. Initial analyses revealed no significant differences between the conditions in [11C]raclopride binding potential (BP) in the caudate, putamen, or ventral striatum. Because previous research suggested that drug-induced dopamine transmission is related to levels of craving and/or hedonic drug effects, the relationship between these variables and [11C]raclopride BP was examined. Craving levels were reduced by smoking but were not systematically related to BP change. However, the hedonic response to smoking was correlated with BP reduction in the caudate (P < 0.001) and posterior putamen (P < 0.05) but not in the ventral striatum. Post hoc analyses revealed that only five of the ten smokers reported mood-elevating effects in response to the smoking procedure. In these subjects, smoking was associated with decreased [11C]raclopride BP in the caudate. On the other hand, among subjects that reported a diminished mood response to smoking there was an increase in BP in the caudate and putamen. These results suggest that pleasurable drug experiences are associated with increased dopamine transmission in the dorsal striatum while unpleasant experiences may be related to decreased dopamine release in this region.

/pdf/the-hedonic-response-to-cigarette-smoking-is-proportional-to-37a2bs9g62.pdf

The hedonic response to cigarette smoking is proportional to dopamine release in the human striatum as measured by positron emission tomography and [11C]raclopride.

Sean P. Barrett

Papers

Effects of expectancy and abstinence on the neural response to smoking cues in cigarette smokers: an fMRI study

Patterns of simultaneous polysubstance use in drug using university students

Characteristics of methylphenidate misuse in a university student sample.

Nicotine Increases Alcohol Self-Administration in Non-Dependent Male Smokers

The hedonic response to cigarette smoking is proportional to dopamine release in the human striatum as measured by positron emission tomography and [11C]raclopride.