David H. Morris

Acute alcohol effects on impulsivity: associations with drinking and driving behavior

AIMS Although drink drivers exhibit higher levels of trait impulsivity, no studies have tested the hypothesis that drink drivers experience increased impulsivity while intoxicated. We tested this hypothesis for two impulsivity constructs: delay discounting and behavioral inhibition. DESIGN A within-subjects study comparing performance of drink drivers and non-drink drivers on behavioral measures of impulsivity in alcohol and no-beverage sessions. SETTING A laboratory setting at the University of Missouri. PARTICIPANTS Twenty-nine young adults who were at least moderate drinkers were recruited from the local community and the University of Missouri. MEASUREMENTS Impulsivity was assessed using the Two Choice Impulsivity Paradigm (TCIP) and the Stop-Signal Task. Participants also completed self-report measures of binge drinking and trait impulsivity. FINDINGS In the no-beverage session, TCIP impulsive choices did not differ between drinking and driving groups (P = 0.93). In the alcohol session, drink drivers made more TCIP impulsive choices on both the ascending (P < 0.01) and descending limb (P < 0.01) of the blood alcohol concentration curve than their peers who did not drink and drive. Drinking and driving groups did not differ on the Stop-Signal Task. Supplementary analyses indicated that effects for the TCIP were not explained by individual differences in trait impulsivity. CONCLUSIONS Individuals who report having three or more drinks before driving show greater impulsivity when under the influence of alcohol than those who do not report heavy drinking before driving.

Increased behavioral economic demand and craving for alcohol following a laboratory alcohol challenge.

BACKGROUND AND AIMS Although increases in subjective alcohol craving have been observed following moderate doses of alcohol (e.g. priming effects), the effects of alcohol consumption on behavioral economic demand for alcohol are largely unstudied. This study examined the effects of alcohol intoxication on alcohol demand and craving. DESIGN A between-subjects design in which participants were randomly assigned to either an alcohol (n = 31), placebo (n = 29) or control (n = 25) condition. SETTING A laboratory setting at the University of Missouri, USA. PARTICIPANTS Eighty-five young adult moderate drinkers were recruited from the University of Missouri and surrounding community. MEASUREMENTS Change in demand for alcohol across time was measured using three single items: alcohol consumption at no cost (i.e. intensity), maximum price paid for a single drink (i.e. breakpoint) and total amount spent on alcohol (i.e. Omax). Alcohol demand at baseline was also assessed using an alcohol purchase task (APT). Craving was assessed using a single visual analog scale item. FINDINGS In the alcohol group compared with the combined non-alcohol groups, intensity, breakpoint and craving increased from baseline to the ascending limb and decreased thereafter (Ps < 0.05; Omax , P = 0.06). Change in craving following alcohol consumption was significantly associated with change in each of the demand indices (Ps < 0.0001). Finally, the demand single items were associated with corresponding indices from the APT (Ps < 0.05). CONCLUSIONS Alcohol demand increases following intoxication, in terms of both the maximum amount people are willing to pay for one drink and the number of drinks people would consume if drinks were free. Behavioral economic measures of alcohol value can complement subjective craving as measures of moment-to-moment fluctuations in drinking motivation following intoxication.

A psychometric evaluation of the Posttraumatic Cognitions Inventory with Veterans seeking treatment following military trauma exposure

Trauma-related beliefs have salient relationships to the development and maintenance of Posttraumatic Stress Disorder (PTSD) following stress exposure. The Posttraumatic Cognitions Inventory (PTCI) has the potential to be a standard assessment of this critical construct. However, some critical aspects of validity and reliability appear to vary by population. To date, the PTCI has not been psychometrically evaluated for use with military-specific traumas such as combat and military sexual trauma (MST). Based on exploratory and confirmatory analyses with 949 Veterans seeking trauma-focused treatment for military traumas, we found a four factor model (negative view of the self, negative view of the world, self-blame, and negative beliefs about coping competence) provided the best fit. In contrast, the original three factor model was not confirmed. Both models demonstrated convergent and discriminative validity. Although gender was associated with PTCI total and factor scores, differences did not persist after controlling for trauma type. MST was associated with higher PTCI scores even when controlling for gender, though the clinical magnitude of these differences is likely negligible. Internal reliability validity was demonstrated with PTCI total and subscale scores.

Separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation

RationaleCaffeine is commonly believed to offset the acute effects of alcohol, but some evidence suggests that cognitive processes remain impaired when caffeine and alcohol are coadministered.ObjectivesNo previous study has investigated the separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation, processes thought to be critical for self-regulation. This was the purpose of the current study.MethodsHealthy, young adult social drinkers recruited from the community completed a flanker task after consuming one of four beverages in a 2 × 2 experimental design: Alcohol + caffeine, alcohol + placebo caffeine, placebo alcohol + caffeine, or placebo alcohol + placebo caffeine. Accuracy, response time, and the amplitude of the N2 component of the event-related potential (ERP), a neural index of conflict monitoring, were examined as a function of whether or not conflict was present (i.e., whether or not flankers were compatible with the target) on both the previous trial and the current trial.ResultsAlcohol did not abolish conflict monitoring or adaptation. Caffeine eliminated conflict adaptation in sequential trials but also enhanced neural conflict monitoring. The combined effect of alcohol and caffeine was apparent only in how previous conflict affected the neural conflict monitoring response.ConclusionsTogether, the findings suggest that caffeine leads to exaggeration of attentional resource utilization, which could provide short-term benefits but lead to problems conserving resources for when they are most needed.

Association of persistent postconcussion symptoms with violence perpetration among substance-using veterans.

Objective: Traumatic brain injury (TBI) and persistent postconcussion symptoms (PPCS) are associated with increased substance use among veterans. Each factor is independently associated with the perpetration of violence; however, little is known about the associations TBI and PPCS have with violence among substance users. This study examined the distinct associations probable TBI and PPCS have with partner aggression (PA) and nonpartner aggression (NPA) in substance-using veterans. Method: Present sample included 810 veterans (6.7% women; Mage = 48.2, SD = 13.3) who completed self-report measures assessing sociodemographic characteristics, past month binge drinking and cocaine use, probable TBI, PPCS, probable posttraumatic stress disorder (PTSD), and chronic pain. Aggression measures included psychological, physical, and injury-related PA and NPA. Results: Bivariate analyses revealed age, probable PTSD, and PPCS were associated with most forms of PA and NPA, whereas race, cocaine use, pain, and TBI severity were mostly associated with NPA. Multivariate negative binomial regression analyses adjusting for other identified risk factors (e.g., age, probable PTSD, and chronic pain) revealed PPCS, but not TBI, was associated with most forms of PA and NPA. Conclusions: Findings highlight the importance of PPCS as a risk factor for PA and NPA in substance-using veterans and have important implications concerning the screening of violence risk.

Associations Between Posttraumatic Stress and Legal Charges Among Substance Using Veterans.

Substance misuse is prevalent among veterans entering the criminal justice system, and is related to recidivism. Research demonstrates that trauma exposure and posttraumatic stress (PTS) symptoms, which commonly co-occur with substance misuse, also increase the risk of legal involvement and recidivism. However, it is unclear whether the associations between trauma, PTS symptoms and violent and nonviolent crime may be conflated by substance use. The aim of the present study was to understand the association between PTS symptoms and criminal justice involvement (both violent and nonviolent crime) among substance-using veterans seeking Veterans Affairs (VA) specialty mental health care after accounting for substance use frequency and demographics including age, gender, and ethnicity. Further, this study examined whether specific clusters of PTS were associated with violent and nonviolent veteran offending. Participants included 697 veterans (52 women) aged 21 to 75 (M = 47.49, SD = 13.51) with a history of trauma exposure. Veterans self-reported past-month PTS symptoms, substance use, and lifetime legal charges. Logistic regression results indicated total PTS symptoms were associated with violent, but not nonviolent charges, above and beyond age, sex, race, cocaine use, and heavy alcohol use. Intrusion symptoms, in particular, were associated with violent charges. Results highlight the utility of examining PTS as a multifaceted construct and have implications for the assessment and treatment needs of justice-involved veterans. For example, the findings suggest that treatment needs appear to differ for those reporting violent or nonviolent offending, with a greater need for assessing and treating PTS for those involved with violent crime.

Association between overall rate of change in rising breath alcohol concentration and the magnitude of acute tolerance of subjective intoxication via the Mellanby method

The magnitude of acute tolerance is a strong predictor of the development of longer‐term chronic tolerance and plays a decisive role in risky decisions (e.g., driving after drinking). Therefore, it is important to identify factors that increase the magnitude of this adaptive process. This study explored whether acute tolerance magnitude varied as a function of the overall rate of increase in breath alcohol concentration (BrAC).

Response to Tucker & Vuchinich (2015): Behavioral economics in the broader context of addiction science

Keywords: Alcohol; behavioral economics; craving; demand; efficient causes, within-person variation.