Choice to view cocaine images predicts concurrent and prospective drug use in cocaine addiction.

Background: Identifying variables that predict drug use in treatment-seeking drug addicted individuals is a crucial research and therapeutic goal. This study tested the hypothesis that choice to view cocaine images is associated with concurrent and prospective drug use in cocaine addiction.

Methods: To establish choice-concurrent drug use associations, 71 cocaine addicted subjects (43 current users and 28 treatment seekers) provided data on (A) choice to view cocaine images and affectively pleasant, unpleasant, and neutral images [collected under explicit contingencies (when choice was made between two fully visible side-by-side images) and under more probabilistic contingencies (when choice was made between pictures hidden under flipped-over cards)]; and (B) past-month cocaine and other drug use.

Methylphenidate enhances executive function and optimizes prefrontal function in both health and cocaine addiction.

Previous studies have suggested dopamine to be involved in error monitoring/processing, possibly through impact on reinforcement learning. The current study tested whether methylphenidate (MPH), an indirect dopamine agonist, modulates brain and behavioral responses to error, and whether such modulation is more pronounced in cocaine-addicted individuals, in whom dopamine neurotransmission is disrupted. After receiving oral MPH (20 mg) or placebo (counterbalanced), 15 healthy human volunteers and 16 cocaine-addicted individuals completed a task of executive function (the Stroop color word) during functional magnetic resonance imaging (fMRI).

Sensitivity to monetary reward is most severely compromised in recently abstaining cocaine addicted individuals: a cross-sectional ERP study.

Recent studies suggest that drug-addicted individuals have a dampened cortical response to non-drug rewards. However, it remains unclear whether recency of drug use impacts this impairment. Therefore, in this event-related potential study, recency of cocaine use was objectively determined by measuring cocaine in urine on study day.

Enhanced midbrain response at 6-month follow-up in cocaine addiction, association with reduced drug-related choice.

Drug addiction is characterized by dysregulated dopamine neurotransmission. Although dopamine functioning appears to partially recover with abstinence, the specific regions that recover and potential impact on drug seeking remain to be determined. Here we used functional magnetic resonance imaging (fMRI) to study an ecologically valid sample of 15 treatment-seeking cocaine addicted individuals at baseline and 6-month follow-up.

Neuroimaging for drug addiction and related behaviors.

In this review, we highlight the role of neuroimaging techniques in studying the emotional and cognitive-behavioral components of the addiction syndrome by focusing on the neural substrates subserving them. The phenomenology of drug addiction can be characterized by a recurrent pattern of subjective experiences that includes drug intoxication, craving, bingeing, and withdrawal with the cycle culminating in a persistent preoccupation with obtaining, consuming, and recovering from the drug. In the past two decades, imaging studies of drug addiction have demonstrated deficits in brain circuits related to reward and impulsivity.

Motivated attention to cocaine and emotional cues in abstinent and current cocaine users--an ERP study.

Event-related potentials (ERPs) are a direct measure of neural activity and are ideally suited to study the time-course of attentional engagement with emotional and drug-related stimuli in addiction. In particular, the late positive potential (LPP) appears to be enhanced following cocaine-related compared with neutral stimuli in human participants with cocaine use disorders (CUD). However, previous studies have not directly compared cocaine-related with emotional stimuli while examining potential differences between abstinent and current cocaine users.

A pattern of perseveration in cocaine addiction may reveal neurocognitive processes implicit in the Wisconsin Card Sorting Test.

The ability to adapt behavior in a changing environment is necessary for humans to achieve their goals and can be measured in the lab with tests of rule-based switching. Disease models, such as cocaine addiction, have revealed that alterations in dopamine interfere with adaptive set switching, culminating in perseveration. We explore perseverative behavior in individuals with cocaine use disorders (CUD) and healthy controls (CON) during performance of the Wisconsin Card Sorting Test (WCST) (N=107 in each group).

Gene x disease interaction on orbitofrontal gray matter in cocaine addiction.

Context: Long-term cocaine use has been associated with structural deficits in brain regions having dopamine-receptive neurons. However, the concomitant use of other drugs and common genetic variability in monoamine regulation present additional structural variability.

Objective: To examine variations in gray matter volume (GMV) as a function of lifetime drug use and the genotype of the monoamine oxidase A gene, MAOA, in men with cocaine use disorders (CUD) and healthy male controls.

Oral methylphenidate normalizes cingulate activity in cocaine addiction during a salient cognitive task.

Anterior cingulate cortex (ACC) hypoactivations during cognitive demand are a hallmark deficit in drug addiction. Methylphenidate (MPH) normalizes cortical function, enhancing task salience and improving associated cognitive abilities, in other frontal lobe pathologies; however, in clinical trials, MPH did not improve treatment outcome in cocaine addiction. We hypothesized that oral MPH will attenuate ACC hypoactivations and improve associated performance during a salient cognitive task in individuals with cocaine-use disorders (CUD).

Disrupted functional connectivity with dopaminergic midbrain in cocaine abusers.

Background: Chronic cocaine use is associated with disrupted dopaminergic neurotransmission but how this disruption affects overall brain function (other than reward/motivation) is yet to be fully investigated. Here we test the hypothesis that cocaine addicted subjects will have disrupted functional connectivity between the midbrain (where dopamine neurons are located) and cortical and subcortical brain regions during the performance of a sustained attention task.

Methodology/principal Findings: We measured brain activation and functional connectivity with fMRI in 20 cocaine abusers and 20 matched controls.

Impaired insight in cocaine addiction: laboratory evidence and effects on cocaine-seeking behaviour.

Neuropsychiatric disorders are often characterized by impaired insight into behaviour. Such an insight deficit has been suggested, but never directly tested, in drug addiction. Here we tested for the first time this impaired insight hypothesis in drug addiction, and examined its potential association with drug-seeking behaviour.

The Substance Use Risk Profile Scale: a scale measuring traits linked to reinforcement-specific substance use profiles.

The Substance Use Risk Profile Scale (SURPS) is based on a model of personality risk for substance abuse in which four personality dimensions (hopelessness, anxiety sensitivity, impulsivity, and sensation seeking) are hypothesized to differentially relate to specific patterns of substance use. The current series of studies is a preliminary exploration of the psychometric properties of the SURPS in two populations (undergraduate and high school students). In study 1, an analysis of the internal structure of two versions of the SURPS shows that the abbreviated version best reflects the 4-factor structure.

Neural mechanisms of anger regulation as a function of genetic risk for violence.

Genetic risk may predispose individuals to compromised anger regulation, potentially through modulation of brain responses to emotionally evocative stimuli. Emphatically expressed, the emotional word No can prohibit behavior through conditioning. In a recent functional magnetic resonance imaging study, the authors showed that healthy males attribute negative valence to No while showing a lateral orbitofrontal response that correlated with their self-reported anger control.

Anterior cingulate cortex hypoactivations to an emotionally salient task in cocaine addiction.

Anterior cingulate cortex (ACC) hypoactivations during cognitive processing characterize drug addicted individuals as compared with healthy controls. However, impaired behavioral performance or task disengagement may be crucial factors. We hypothesized that ACC hypoactivations would be documented in groups matched for performance on an emotionally salient task.

Dopaminergic response to drug words in cocaine addiction.

When exposed to drug conditioned cues (stimuli associated with the drug), addicted individuals experience an intense desire for the drug, which is associated with increased dopamine cell firing. We hypothesized that drug-related words can trigger activation in the mesencephalon, where dopaminergic cells are located. During functional magnetic resonance imaging (fMRI), 15 individuals with cocaine use disorders and 15 demographically matched healthy control subjects pressed buttons for color of drug-related versus neutral words.

Enhanced choice for viewing cocaine pictures in cocaine addiction.

Background: Individuals with cocaine use disorder (CUD) chose cocaine over nondrug rewards. In two newly designed laboratory tasks with pictures, we document this modified choice outside of a cocaine administration paradigm.

Methods: Choice for viewing cocaine, pleasant, unpleasant, or neutral pictures--under explicit contingencies (choice made between two fully visible side-by-side images) and under more implicit contingencies (selections made between pictures hidden under flipped-over cards)--was examined in 20 CUD and 20 matched healthy control subjects.

Compromised sensitivity to monetary reward in current cocaine users: an ERP study.

We studied modulation of the P300 by monetary reward expected to be received on a sustained attention task in 18 individuals with current cocaine use disorders (CUD) and 18 control subjects. Results in the controls revealed sensitivity to money as measured with P300 amplitude and speed of behavioral response and their intercorrelations. In contrast, despite generally faster P300 waveforms and higher self-reported interest in the task, individuals with CUD did not display these responses to money versus nonreward; at the behavioral level, this impairment correlated with frequency of recent cocaine use.

The neuropsychology of cocaine addiction: recent cocaine use masks impairment.

Individuals with current cocaine use disorders (CUD) form a heterogeneous group, making sensitive neuropsychological (NP) comparisons with healthy individuals difficult. The current study examined the effects on NP functioning of four factors that commonly vary among CUD: urine status for cocaine (positive vs negative on study day), cigarette smoking, alcohol consumption, and dysphoria. Sixty-four cocaine abusers were matched to healthy comparison subjects on gender and race; the groups also did not differ in measures of general intellectual functioning.