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Background and Objectives: This study examined how a promoter variant of TH (rs10770141) affects subjective effects of cocaine in 65 nontreatment-seeking individuals with cocaine dependence., Methods: Participants received cocaine/saline intravenously, and TH genotypes were evaluated., Results: Homozygous individuals for the minor T allele reported greater "good" and "bad" subjective effects to cocaine than those with the major C allele., Discussion and Conclusions: TH rs10770141 modulates subjective effects of cocaine in participants with cocaine dependence., Scientific Significance: These results are among the first to indicate that homozygosity of the T allele of rs10770141 modulates greater sensitivity to cocaine., (© 2023 The American Academy of Addiction Psychiatry (AAAP).)

Background and Objectives: No medication has Food and Drug Administration approval for cannabis use disorder (CUD), and most medication development focuses on the withdrawal syndrome. We evaluated the effects of short-term treatment using the α-2A-adrenergic receptor agonist, guanfacine, on withdrawal symptoms in volunteers with CUD and a history of early onset of cannabis use., Methods: Non-treatment-seeking healthy volunteers (n = 7) who met the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition criteria for CUD participated in a two-phase, within-subjects study. Volunteers received placebo or guanfacine (3 mg/day) for the first 8-day inpatient study and the alternative medication for the second 8-day inpatient study. On day 1 of both treatment periods, participants received 30 mg of synthetic Δ 9 -tetrahydrocannabinol for standardization of abstinence onset. On days 2 to 7, participants received study medication. Cannabis withdrawal symptoms, sleep, craving, and physiology were assessed on all inpatient days., Results: Compared with placebo, guanfacine did not show significant effects on withdrawal, craving, or sleep, although there were trends for guanfacine to increase positive mood symptoms and decrease craving-associated compulsivity., Discussion and Conclusions: Compared with former studies, we could not prove significant improvement in sleep or decrease of negative symptoms, but we found trends for increased positive mood symptoms. Our data did not show significant effects of guanfacine on withdrawal symptoms or craving. Due to early and longer cannabis use, our subjects indicate a great severity of illness increasing the likelihood of treatment resistance., Scientific Significance: On the basis of trends demonstrated here and other lines of evidence, further investigation is warranted regarding the utility of guanfacine as a potential treatment for CUD. (Am J Addict 2019;00:1-10)., (© 2019 American Academy of Addiction Psychiatry.)

Background and Objectives: Recent surveys confirm continued increases in the use of electronic-cigarettes (e-cigarettes) in adolescents and adults. Users often state that e-cigarettes reduce tobacco craving and withdrawal symptoms in addition to their smoking. Data from laboratory studies and clinical trials have confirmed these statements, though there are inconsistencies in the outcomes. In this pilot study, we set out to evaluate the effects of e-cigarettes, as compared to the participants' own cigarettes, on baseline craving and smoking severity., Methods: Using a within-subjects, placebo-controlled study design, 15 tobacco-dependent, e-cigarette naïve participants sustained abstinence overnight. They completed distinct phases of this protocol during four separate study sessions. Participants were randomized to an e-cigarette device containing one of three doses of nicotine (0, 18, or 36 mg/ml) or their own cigarette. Each study visit was ~3 hours long and separated by at least 7 days. Visits included assessments of craving and smoking severity., Results: The data showed that after 10 puffs in both the Own cigarette and e-cigarette conditions, breath carbon monoxide levels increased significantly in the former but not the latter. Questionnaire of Smoking Urges and Choices to Smoke scores were not statistically different across groups after two distinct bouts of 10 puffs each. Additionally, E-cigarette Perceptions Questionnaire responses were not significantly different according to dose., Conclusion and Scientific Significance: This experiment provides data demonstrating that e-cigarettes did not reduce craving or smoking severity in e-cigarette naïve users. However, since this was a pilot study, the conclusions that can be drawn are limited. (Am J Addict 2019;28:361-366)., (© 2019 American Academy of Addiction Psychiatry.)

Background and Objectives: The endogenous cannabinoid anandamide (AEA), an agonist at type-1 cannabinoid (CB1) receptors, is metabolized by fatty acid amide hydrolase (FAAH). The common variant rs324420 C->A within the FAAH gene on chromosome 1 codes for a missense substitution (Pro129Thr), resulting in decreased FAAH activity and increased endocannabinoid potentiation. This FAAH variant has been linked to alterations in mood and stress reactivity, as well as being independently linked to increased risk for addiction. We hypothesized that cocaine use disordered (CUD) participants with the FAAH Pro129 Thr variant would exhibit a distinct profile of cocaine-induced subjective effects in the laboratory., Methods: A total of 70 CUD participants received intravenous doses of saline (placebo, 0 mg) and cocaine (20, 40 mg) in a lab-controlled setting and rated 10 subjective effect measures prior to and following saline and cocaine administration, using a Visual Analog Scale (VAS)., Results: The variant allele was associated with increased cocaine-induced subjective ratings for "Drug Effect," "High," and "Depressed." The prevalence of the variant allele A and the AA genotypes were greater in our CUD group than in the general population (A allele: 47% vs. 34%; AA genotype: 30% vs. 13%; p < .05). Finally, the reported amount and frequency of tobacco and cocaine use was higher in subjects with the AC/AA allele., Conclusions and Scientific Significance: These results add to existing evidence that this variant of the FAAH genotype may be over-represented among those who have CUD, and this over-representation may result from greater subjective responses to cocaine administration. (Am J Addict 2018;27:567-573)., (© 2018 American Academy of Addiction Psychiatry.)

Background and Objectives: Delay discounting is associated with numerous clinically significant aspects of substance use disorders (SUDs). Recent studies have demonstrated that different models for assessing discounting may result in disparate conclusions. The current study compared two discounting tasks: money now versus money later (M-M) and methamphetamine now versus money later (MA-M) among non-treatment seeking individuals (N = 59) with methamphetamine use disorder (MAUD). Results from each task were assessed using three different models for assessing delay discounting., Methods: Discounting data were fit to three models of discounting, log k using Mazur's hyperbolic formula, area under the curve (AUC), and an alternative AUC model in which the delay values have been log transformed (AUClog)., Results: For both discounting tasks, the distribution of model-related outcomes were normally distributed when using log k and AUClog, but skewed for AUC. Discounting in the MA-M task was significantly greater compared to the M-M task when using log k and AUClog but not AUC., Conclusion: To our knowledge, the current study is the first to report significantly greater discounting in a MA-M relative to M-M discounting task among individuals with MAUD, an outcome consistent with other psychomotor stimulants and drugs of abuse., Scientific Significance: The differential results observed across the three discounting models reaffirm potential issues with AUC noted in recent studies and highlight that researchers must be cautious when deciding on their final model of discounting. (Am J Addict 2018;XX:1-8)., (© 2018 American Academy of Addiction Psychiatry.)

Background and Objectives: Chronic cocaine use has been linked to several abnormalities in cardiac functioning. The objective of this study was to further characterize baseline heart rate and electrocardiograph (ECG) profiles of individuals with cocaine use disorder (CUD) by evaluating demographic and drug use variables that may impact cardiovascular profiles., Methods: Participants with CUD (n = 335, primarily African-American males) provided demographic and drug use data and ECG profiles (eg, heart rate, PR Interval, QRS, and QTc) were obtained via 12-lead ECG., Results: Forty-eight percent and ten percent of cocaine users met criteria for sinus bradycardia (heart rate ≤60) and severe bradycardia (heart rate ≤50), respectively. Females had significantly higher heart rate (p = .020, d = .30) and QTc (p < .001, d = .75) and significantly lower QRS (p = .002, d = .42) in comparison to males. Those who were cocaine positive had higher QTc (p = .025, d = .26) with a higher prevalence of bradycardia (chi-square = 3.91, p = .048) than those who were negative. Cocaine users who also used alcohol had significantly lower PR Interval (p = .003, d = .36), QRS (p = .014, d = .29), and QTc (p = .037, d = .25) than those who denied alcohol use., Conclusions: These findings characterize the baseline heart rate and ECG profiles of individuals with CUD, confirm previous reports of cocaine-induced alterations in cardiovascular function, and demonstrate factors impacting cardiovascular profiles., Scientific Significance: While exploratory, these results suggest the presence of bradycardia may serve as a useful biomarker for initiating therapy for individuals with CUD and averting potential adverse cardiovascular events. Future prospective studies are needed to assess this possibility. (Am J Addict 2017;26:221-227)., (© 2017 American Academy of Addiction Psychiatry.)

Background and Objectives: The anterior cingulate cortex (ACC) is hypothesized to be involved in decision making and emotion regulation. Previous observations of drug dependent individuals indicate that substance dependence may be associated with cingulum white matter abnormalities. The present study evaluated cingulum white matter in cigarette smokers., Methods: Diffusion tensor imaging (DTI) in adult tobacco smokers and healthy non-smoker controls (total N = 70) was performed in a 3T Siemens Trio MRI scanner., Results: Analyses of DTI tractography of the cingulum in tobacco-smoking individuals and controls indicated that tobacco abusers have significantly reduced fractional anisotropy (FA) in the right cingulum. In addition, FA in the left cingulum white matter was negatively associated with the number of cigarettes smoked per day and the Fagerstrom test for nicotine dependence, a self-report measure of tobacco dependence severity., Conclusions: The white matter of the cingulum is altered in a non-symmetrical way in tobacco smokers. An inverse relationship between FA and reported number of cigarettes per day was observed. Previous studies have also noted altered neural connectivity in cigarette smokers using similar methods. Similar white matter differences in the cingulum have been observed in methamphetamine dependent individuals and patients with dementia, which suggests that the cingulum may be altered by mechanisms not specific to tobacco exposure., Scientific Significance: By better understanding the effects of tobacco abuse on the brain, we hope to gain insight into how drug dependence influences the neurological foundations of behavior., (© 2016 American Academy of Addiction Psychiatry.)

Modafinil improves working memory in healthy subjects and individuals diagnosed with schizophrenia and Attention Deficit/Hyperactivity Disorder, though the effects of modafinil have not been evaluated on working memory in methamphetamine-dependent subjects. This double-blind, placebo-controlled study evaluated whether a daily dose of 400 mg of modafinil, administered over three consecutive days, would enhance performance on a measure of working memory relative to test performance at baseline and following 3 days of placebo administration in 11 methamphetamine addicted, nontreatment-seeking volunteers. The results revealed that participants demonstrating relatively poor performance on the third day of a 3-day washout period (ie, at baseline), showed significant improvement on measures of working memory, but not on measures of episodic memory or information processing speed. In contrast, for participants demonstrating relatively high performance at baseline, modafinil administration did not affect test scores. The findings provide an initial indication that modafinil can reverse methamphetamine-associated impairments in working memory.

It has long been postulated that stress increases the risk of drug abuse and relapse. The principal goal of this project was to evaluate the effects of verbal recall of a recent stress experience (specifically meaningful to each individual) on physiological and subjective measures in cocaine-addicted participants. Subjects described a recent stressful non-drug-related experience and a neutral non-stressful experience, and then completed mood and drug effect questionnaires, while heart rate and blood pressure were recorded. Participants (N = 25) were predominantly African American and male. As a group, participants used cocaine for more than 15 years and approximately 18 of the last 30 days, and a majority reported use of nicotine and/or alcohol. All participants were evaluated during a time in which they tested positive for cocaine metabolite. On a scale of 1-10, participants reported their verbal recall of a recent stress event as highly stressful and their verbal recall of a recent neutral event as non-stressful (p < 0.0001). The self-reported vividness of this recall was high (>8 out of 10) for both the stress and neutral events. Heart rate and systolic and diastolic blood pressure did not differ after verbal recall of either stress or neutral events. Similarly, self-reported subjective effects (including ratings of anxiety and craving for cocaine) did not differ after verbal recall of either stress or neutral events. In summary, despite the fact that participants recounted highly stressful and vivid memories, this experience did not elicit significant changes in cardiovascular or subjective effects. These data suggest that simply recalling a stressful event may not be a sufficient enough stimulus to contribute to craving or relapse in cocaine-addicted individuals.

A variety of preclinical models have been constructed to emphasize unique aspects of addiction-like behavior. These include Negative Reinforcement ("Pain Avoidance"), Positive Reinforcement ("Pleasure Seeking"), Incentive Salience ("Craving"), Stimulus Response Learning ("Habits"), and Inhibitory Control Dysfunction ("Impulsivity"). We used a survey to better understand why methamphetamine-dependent research volunteers (N = 73) continue to use methamphetamine, or relapse to methamphetamine use after a period of cessation of use. All participants met DSM-IV criteria for methamphetamine abuse or dependence, and did not meet criteria for other current Axis I psychiatric disorders or dependence on other drugs of abuse, other than nicotine. The questionnaire consisted of a series of face-valid questions regarding drug use, which in this case referred to methamphetamine use. Examples of questions include: "Do you use drugs mostly to make bad feelings like boredom, loneliness, or apathy go away?", "Do you use drugs mostly because you want to get high?", "Do you use drugs mostly because of cravings?", "Do you find yourself getting ready to take drugs without thinking about it?", and "Do you impulsively take drugs?". The scale was anchored at 1 (not at all) and 7 (very much). For each question, the numbers of participants rating each question negatively (1 or 2), neither negatively or affirmatively (3-5), and affirmatively (6 or 7) were tabulated. The greatest number of respondents (56%) affirmed that they used drugs due to "pleasure seeking." The next highest categories selected were "impulsivity" (27%) and "habits"(25%). Surprisingly, many participants reported that "pain avoidance" (30%) and "craving" (30%) were not important for their drug use. Results from this study support the contention that methamphetamine users (and probably other drug users as well) are more heterogeneous than is often appreciated, and imply that treatment development might be more successful if treatments targeted subtypes of patients, though a range of limitations to the approach used are acknowledged.

The primary objective of this study was to compare and contrast psychotic symptoms reported by cocaine- and methamphetamine-dependent individuals. Participants included 27 cocaine-dependent and 25 methamphetamine-dependent males, as well as 15 cocaine-dependent and 18 methamphetamine-dependent females. After screening, participants were excluded if they met criteria for any Axis I diagnosis other than nicotine dependence, or methamphetamine or cocaine dependence (ie, participants had to use either methamphetamine or cocaine but were excluded if they met dependence criteria for both). The participants were administered the newly developed Psychotic Symptom Assessment Scale (PSAS), which assesses psychotic symptoms. A high proportion of both cocaine- and methamphetamine-dependent men and women reported delusions of paranoia and auditory hallucinations. However, during the abstinent and intoxicated conditions, methamphetamine-dependent men and women were more likely than cocaine-dependent men and women to report psychotic symptoms. Future studies will compare psychotic symptoms reported by non-dependent recreational stimulant users to stimulant-dependent individuals.

The goal of the present investigation was to determine predictors of cardiovascular response to methamphetamine administrated in the laboratory. Heart rate (HR) and blood pressure (BP) were measured at baseline and at several time points following the administration of methamphetamine or saline placebo. One-way ANOVA was used to determine the differences between female and male subjects in their cardiovascular response. In male subjects, linear regression and one-way ANOVA were used to determine the influence of potential predictors on cardiovascular response, including age, weight, drug use indicators, concurrent use of other substances, route of administration, and race. Methamphetamine administration provoked significant increases in HR and BP, as compared to placebo. Female gender was associated with larger peak change in diastolic BP following administration. Baseline HR and BP were found to be strong predictors of cardiovascular response to methamphetamine administration in male subjects. Lifetime use and recent use of methamphetamine and nicotine did not predict cardiovascular response to methamphetamine. Recent alcohol use was associated with increased peak change in diastolic BP. Also, current use of cannabis was negatively correlated with peak HR change. Male cannabis users show lower peak change in HR as compared to non-cannabis users. As compared to methamphetamine smokers, intravenous users demonstrated higher peak change in diastolic BP following drug administration. Race did not have a significant effect on cardiovascular response. Taken together, these findings may help in the prevention and treatment of cardiovascular events in a population at high risk of premature morbidity and mortality.