Jean-Marc Assaad

Cognitive–Neuropsychological Function in Chronic Physical Aggression and Hyperactivity

Histories of violence and of hyperactivity are both characterized by poor cognitive–neuropsychological function. However, researchers do not know whether these histories combine in additive or interactive ways. The authors tested 303 male young adults from a community sample whose trajectories of teacher-rated physical aggression and motoric hyperactivity from kindergarten to age 15 were well defined. No significant interaction was found. In a 1st model, both histories of problem behavior were independently associated with cognitive–neuropsychological function in most domains. In a 2nd model controlling for IQ, general memory, and test motivation, the 3 working-memory tests (relevant to executive function) remained associated with physical aggression, and 1 remained associated with hyperactivity. These results support an additive model.

Salivary testosterone and aggression, delinquency, and social dominance in a population-based longitudinal study of adolescent males

Testosterone (T) has been found to have a stimulating effect on aggressive behavior in a wide range of vertebrate species. There is also some evidence of a positive relationship in humans, albeit less consistently. In the present study we investigated the relationship between T and aggression, dominance and delinquency over time, covering a period from early adolescence to adulthood. From a large population-based sample (n = 1.161) a subgroup of 96 boys was selected whose behavior had been assessed repeatedly by different informants from age 12 to 21 years, and who had provided multiple T samples over these years of assessment. On the whole, a decrease in aggressive and delinquent behavior was observed in a period in which T rises dramatically. Boys who developed a criminal record, had higher T levels at age 16. In addition, positive associations were observed between T and proactive and reactive aggression and self-reported delinquent behavior. Over the pubertal years different forms of aggressive and delinquent behavior were positively related to T, which may indicate that specific positive links are dependent on the social setting in which this relationship is assessed.

Heightened Heart Rate Response to Alcohol Intoxication Is Associated With a Reward-Seeking Personality Profile

BACKGROUND The psychomotor stimulant theory of addiction posits that sensitivity to the positively rewarding properties of alcohol puts certain individuals at higher risk for alcohol abuse. A valid and reliable index of overactivation in the reward system has been a heightened baseline heart rate (HR) increase on the ascending limb of the blood alcohol curve. The main goal of this study was to investigate the relationship between this HR response and a questionnaire measuring sensitivity to reward and sensitivity to punishment. Additional goals included looking at (1). the association between a high HR response and various personality traits (hopelessness/introversion, anxiety sensitivity, impulsivity, and sensation-seeking) and (2). the relationship between these personality traits and stimulant use. METHODS A total of 18 low- and 19 high-HR responders completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), the Substance Use Risk Profile Scale (SURPS), and a modified version of the Addiction Severity Index. RESULTS High-HR responders obtained significantly higher scores than low-HR responders on the sensitivity to reward scale of the SPSRQ, as well as increased sensation-seeking scores on the SURPS. High-HR responders were not at significantly higher risk of having used stimulants, but stimulant use was associated with higher impulsivity scores on the SURPS. CONCLUSIONS Novelty/sensation-seeking is among the personality traits that have been linked to heavy alcohol use. This study suggests that reward sensitivity might mediate the relationship between this personality profile and drinking behavior.

Aggressive disposition, alcohol, and aggression

This study investigated the effect of aggressive disposition on intoxicated and non-intoxicated aggressive behavior, Prior aggressiveness was measured with a structured questionnaire, Based on a bipartite split of scores, 28 subjects were assigned to the high aggressor group, and 29 to the low aggressor group. Subjects in both disposition groups were then randomly assigned to either a drunk or sober condition, and participated in a competitive reaction time task involving the administering and receiving of electric shocks to/from a fictitious opponent under conditions of high and low provocation. Aggression was defined as shock level intensity delivered to the sham opponent. When highly provoked, sober high aggressors were significantly more aggressive than low aggressors, thus validating the measure of aggressive disposition. When intoxicated, highly provoked individuals in both the high and low aggressive disposition groups attained equal levels of aggression, It was low aggressors who responded to escalated provocation with a significant increase in aggression responding when intoxicated. These results lend support to the notion that a pharmacological effect of alcohol can increase aggressive behaviour.

The neurocognition of conduct disorder behaviors: specificity to physical aggression and theft after controlling for ADHD symptoms

There is growing evidence that among the different conduct disorder (CD) behaviors, physical aggression, but not theft, links to low neurocognitive abilities. Specifically, physical aggression has consistently been found to be negatively related to neurocognitive abilities, whereas theft has been shown to be either positively or not related to neurocognition. The specificity of these links needs further examination because attention deficit hyperactivity disorder (ADHD) links to both physical aggression and neurocognitive variation. The development of self-reported physical aggression and theft, from age 11 to 17 years, was studied in a prospective at-risk male cohort via a dual process latent growth curve model. Seven neurocognitive tests at age 20 were regressed on the growth parameters of physical aggression and theft. The links between neurocognition and the growth parameters of physical aggression and theft were adjusted for ADHD symptoms at ages 11 and 15 (parent, child and teacher reports). Results indicated that verbal abilities were negatively related to physical aggression while they were positively associated with theft. However, inductive reasoning was negatively associated with increases in theft across adolescence. Symptoms of ADHD accounted for part of the neurocognitive test links with physical aggression but did not account for the associations with theft. These differences emphasize the importance of examining specific CD behaviors to better understand their neurodevelopmental mechanisms. They also suggest that youth who engage in different levels of physical aggression or theft behaviors may require different preventive and corrective interventions.

BRIEF REPORT Exaggerated Ethanol-Induced Cardiac Reactivity as an Indicator of Increased Risk for Gambling

Pathological gambling and alcohol dependence show a high rate of co-occurrence. Some individuals at risk for alcohol dependence display an exaggerated heart rate (HR) increase following alcohol consumption, a characteristic suggesting sensitivity to reward. This study examined whether exaggerated ethanol-induced cardiac reactivity was associated with increased gambling behaviors. One hundred five young men (M = 20.13 years, SD = 1.07) consumed 1 ml of ethanol (95% volume) per kilogram of body weight. HR was measured and participants completed the South Oaks Gambling Screen (SOGS; H. R. Lesieur & S. B. Blume, 1987). Those with higher intoxicated HRs reported significantly greater scores on the SOGS (p = .02). This suggests that ethanol-induced HR increase is a possible marker for addictive disorders.

A longitudinal study of pain sensitivity and blood pressure in adolescent boys: results from a 5-year follow-up.

A growing literature has observed a significant reduction in pain sensitivity among hypertensive animals and humans. It is uncertain whether a reduced sensitivity to pain can be observed in nonnotensive individuals who go on to develop high blood pressure. Blood pressure (BP) was reassessed in one hundred fifteen 19-year-old boys initially tested at age 14, when they were also presented with a pain stimulus (mechanical finger pressure). Hierarchical regression analyses indicated that information regarding pain tolerance improved prediction of changes in systolic and diastolic blood pressure beyond that afforded by differences in BP at age 14, parental history of hypertension, and body mass index. These analyses suggest that pain sensitivity may be associated with physiological processes involved in the development of sustained high blood pressure.

Aggressiveness, family history of alcoholism, and the heart rate response to alcohol intoxication.

Some sons of male alcoholics (SOMAs) are characterized by an increased heart rate (HR) response to alcohol intoxication, which is thought to reflect increased sensitivity to alcohol-induced reward. Such a response has also been related to increased physical aggression. However, the confounding effect of aggression in SOMAs may be obscuring the interpretation of these findings. The HR response to alcohol was therefore assessed in 4 groups: high/low aggressive SOMAs and high/low aggressive non-SOMAs. Results indicate that aggressive SOMAs had the highest intoxicated HR response and that they reported the most alcohol consumption. This suggests that in some cases the high comorbidity between alcohol misuse and aggression is related to an increased sensitivity to alcohol-induced reward.

Intoxicated behavioral disinhibition and the heart rate response to alcohol

This study examined the association between the heart rate (HR) response to alcohol intoxication, which is thought to reflect sensitivity to alcohol-induced reward and alcohol-induced behavioral disinhibition. High- and low-HR responders to alcohol participated in a go/no-go task, under sober and intoxicated conditions. Errors of commission on this task have previously been related to behavioral disinhibition. High-HR responders made more intoxicated commission errors as compared with low-HR responders. High-HR responders also reported increased alcohol consumption, and controlling for the latter did not alter the significant association between high-HR responders and increased intoxicated errors of commission. These results are consistent with previous findings of an increased risk for addictive and disinhibited behavioral propensities in individuals with a high-HR response to alcohol intoxication.