Lance O. Bauer

Obesity, smoking, and conduct problems have all been associated with decrements in brain function. However, their additive and interactive effects have rarely been examined. To address the deficiency, we studied P300a and P300b electroencephalographic potentials in 218 women grouped by the presence versus absence of: (1) a BMI ≥ 30 kg/m²; (2) recent smoking; and (3) ≥ 2 childhood conduct problems. Analyses revealed smaller P300a and P300b amplitudes over the posterior scalp among recent smokers versus nonsmokers. No corresponding group differences were found in P300 latencies or frontal scalp amplitudes. The most interesting analysis result was an interaction between conduct problems and obesity limited to the frontally generated P300a component: its latency was significantly greater in women with both attributes than in those with either or neither attribute. An exploratory ANOVA, substituting the genotype of a GABRA2 SNP for conduct problems, also demonstrated an interaction with obesity affecting P300a latency. It is hypothesized that conduct problems, and a conduct‐problem‐associated GABRA2 genotype, decrease the age‐of‐onset and/or increase the lifetime duration of obesity. As a result, they may potentiate the adverse effects of obesity on frontal white matter and thereby increase P300a latency. Smoking may affect brain function by a different mechanism to reduce posterior scalp P300a and P300b amplitudes while preserving frontal scalp P300a latency and amplitude. (Am J Addict 2010;00:1–10)

Aim: The goal was to examine the relationship between a risk factor for poor cognitive control and a health outcome of growing public significance – an excess body mass – among adolescents. Methods: To this end, 109 adolescents aged 14–20 years were recruited and assigned to 1 of 4 groups defined by the crossing of the absence versus presence of a parental history (PH) of externalizing disorders with a body mass index (BMI) percentile (BMIP) Results: The analyses revealed a synergistic interaction between BMIP rank, PH and trial type: the increase in P300 latency and the decrease in response accuracy, elicited by the presence of interfering information, were markedly greater in high-BMIP subjects with a PH of externalizing disorders than in the other subject groups. Analyses of a later component, the N450, previously associated with the Stroop interference effect, revealed no effect of BMI or PH. Conclusions: We conclude that subjects with both a PH of externalizing disorders and an excess BMI constitute a unique group that is less able to resolve cognitive conflict than others. The excessive delay in P300 evoked by conflicting response demands in these subjects may be a marker of a heritable factor that increases risk for both excess body mass and substance use disorders.

Research on electroencephalographic (EEG) correlates of substance use has a long history. The present paper provides a review of recent studies −2001 to the present—with a focus on EEG findings in human participants characterized by a history of chronic substance use, abuse or dependence. In some areas (e.g., alcohol and cocaine dependence), the field has attempted to build upon earlier work by incorporating different methodologies or pursuing research questions of a transdisciplinary nature. New areas of inquiry, such as the investigation of EEG differences among users of ecstasy (MDMA) and methamphetamine, have emerged, primarily as a result of an alarming rise in popularity of these drugs.

The objective of the study was to identify predictors of obesity. One hundred eleven nonobese and 48 obese HIV‐1 seropositive patients provided information on medical history and other characteristics. They were then asked to detect the passage of 2‐s time intervals while the contingent negative variation (CNV) was recorded. Obese patients were healthier, more likely to be receiving Highly Active Antiretroviral Therapy, and less likely to be substance dependent. Obese patients also exhibited a greater CNV slope and responded prematurely. A path model suggested that CD4+count and protease inhibitor use directly predicted obesity. Depression had no direct effect. However, when incorporated into a hypothetical construct, “mood dysregulation,” that also included childhood conduct problems and stimulant dependence, the shared variance among the indicators did predict obesity. This relationship was mediated through premature response preparation (anterior scalp CNV amplitude) and its hypothesized association with impatience/impulsivity.

Although hypertension and alcohol dependence have been linked by epidemiological surveys and clinical observations, their interactive effects on brain function have rarely been tested. The present study involved the recording of P300 event related potentials (ERP) from 106 middle-aged African-American adults assigned to one of four groups: normotensive/nondependent (n = 56), hypertensive/nondependent (n = 11), normotensive/dependent (n = 27), and hypertensive/dependent (n = 12). The numbers of Nicotine Dependence, Major Depressive Disorder, and Conduct Disorder symptoms were specified as covariates within a 2 by 2 factorial design. ERPs were recorded during separate visual and auditory oddball tasks. The major result was a synergistic effect of hypertension and alcohol dependence on auditory P300 latency: the combination of both factors was associated with greater slowing than the sum of their independent effects. Future studies should continue to examine the potential synergistic effects of alcohol dependence and hypertension with a view toward identifying and reducing neurophysiological decrements and stroke risk among middle-aged patients.

Several studies have demonstrated that antiretroviral therapy diminishes the adverse effects of HIV/AIDS on brain function. Yet, few studies have examined the role of comorbid psychiatric disorders in limiting the magnitude of recovery. The present study examined the effects of the presence versus absence of one such disorder – antisocial personality disorder (ASPD) – on brain function in an HIV-1 seronegative control group (n = 68) and in HIV-1 seropositive patients receiving (n = 26), versus not receiving (n = 71), antiretroviral treatment. The primary dependent measures of brain function were the amplitude, latency, and topography of the P300 event-related potential. ANCOVA revealed a significant main effect of ASPD as well as an interaction between ASPD and HIV-1/treatment status. Participants with ASPD exhibited a significant decrement in frontal P300 amplitude in comparison to the ASPD-negative groups. More importantly, further analyses showed that ASPD blunted the decrement in P300 accompanying untreated HIV/AIDS as well as the improvement in P300 accompanying antiretroviral treatment. The results suggest that P300 is minimally improved by antiretroviral therapy among HIV-1 seropositive patients with comorbid ASPD. The lack of antiretroviral efficacy is not easily explained by poor medication compliance. The diminished response to treatment is more likely related to a pre-existing neurophysiological decrement localized to the same brain regions where HIV/AIDS and antiretroviral treatment exert their maximal effect.

Objectives: Balance and gait problems have repeatedly been mentioned in case descriptions of patients infected with Human Immunodeficiency Virus (HIV-1). Objective evidence of these problems has rarely been reported, however. Furthermore, the extent to which balance and gait are influenced by antiretroviral medications or comorbid psychiatric disorders has rarely been examined. Design: The study compared 78 HIV-1 seronegative volunteers to 28 HIV/AIDS patients receiving no antiretroviral therapy, 25 patients receiving only nucleoside analogue therapy, and 37 patients receiving Highly Active Antiretroviral Therapy (HAART). Methods: The dependent measures included Equilibrium Quotient scores recorded during 3 subtests of the Sensory Organization Test (SOT), the number of falls during each subtest, the functional base of support, gait speed and cadence, single leg balance time, proximal strength, and vibrotactile threshold of the foot. The analysis employed the number of alcohol and drug abuse problems, depression severity, and body mass index as covariates. Results: ANCOVAs revealed significant decrements in the 3 HIV-1 seropositive groups relative to the control group on Equilibrium Quotient scores during the most difficult of the SOT subtests (sway-referenced support surface with eyes-closed). HIV/AIDS patients also exhibited a smaller functional base of support and greater vibrotactile thresholds. Antiretroviral treatment did not affect balance; but, it did alter sensory threshold in a complex manner. Conclusions: HIV/AIDS is associated with reliable decrements in balance and peripheral sensory function which are variably sensitive to antiretroviral treatment. The implications of these findings for mobility, and workplace or operator safety, should be contemplated.