Item response theory modeling of substance use: An index based on 10 drug categories.

This study examined the psychometric characteristics of an index of substance use involvement using item response theory. The sample consisted of 292 men and 140 women who qualified for a Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) substance use disorder (SUD) diagnosis and 293 men and 445 women who did not qualify for a SUD diagnosis. The results indicated that men ha4 a higher probability of endorsing substance use compared with women. The index significantly predicted health, psychiatric, and psychosocial disturbances as well as level of substance use behavior and severity of SUD after a 2-year follow-up. Finally, this index is a reliable and useful prognostic indicator of the risk for SUD and the medical and psychosocial sequelae of drug consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validation of the Adolescent Drug Use Screening Inventory: Preliminary findings.

Documented the validity of the Substance Use and Psychiatric Disorder scales of the newly developed Drug Use Screening Inventory (DUSI). 25 adolescents (mean age 15.6 yrs) were administered the DUSI. Results were correlated with the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) and Diagnostic and Statistical Manual of Mental Disorders-III-Revised (DSM-III-R) substance abuse symptoms. Significant positive correlations were observed between number of symptoms on the DSM-III—R checklist and severity scores on the Substance Use, Health Status, Psychiatric Disorder, Social Skills, Family System, School, Work, and Peer Relations scales of the DUSI. Number of psychiatric symptoms reported on the K-SADS correlated with severity scores on the Substance Use, Behavior Problems, Health Status, and Psychiatric Disorder scales of the DUSI. Drug use was also related to psychosocial disturbances in this sample of adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Potential Improvements in Shock-Mitigation Efficacy of a Polyurea-Augmented Advanced Combat Helmet

The design of the currently used Advanced Combat Helmet (ACH) has been optimized to attain maximum protection against ballistic impacts (fragments, shrapnel, etc.) and hard-surface collisions. However, the ability of the ACH to protect soldiers against blast loading appears not to be as effective. Polyurea, a micro-segregated elastomeric copolymer has shown superior shock-mitigation capabilities. In the present work, a combined Eulerian/Lagrangian transient non-linear dynamics computational fluid/solid interaction analysis is used to investigate potential shock-mitigation benefits which may result from different polyurea-based design augmentations of the ACH. Specific augmentations include replacement of the currently used suspension-pad material with polyurea and the introduction of a thin polyurea internal lining/external coating to the ACH shell. Effectiveness of different ACH designs was quantified by: (a) establishing the main forms of mild traumatic brain injury (mTBI); (b) identifying the key mechanical causes for these injuries; and (c) quantifying the extents of reductions in the magnitude of these mechanical causes. The results obtained show that while the ACH with a 2-mm-thick polyurea internal lining displays the best blast mitigation performance, it does not provide sufficient protection against mTBI.     

Social dominance mediates the association of testosterone and neurobehavioral disinhibition with risk for substance use disorder.

This investigation determined the influence of testosterone and neurobehavioral disinhibition (ND) on risk for substance use disorder (SUD). Testosterone level during puberty was hypothesized to promote social dominance associated with norm-violating behavior that, in turn, predisposes individuals to use of illicit drugs and, subsequently, SUD. Using a prospective paradigm, the authors recruited 179 boys (mean age=11.62 years, SD=0.88) and followed up when participants were ages 12-14, 16, 19, and 22. Results indicated that social dominance/norm-violating behavior (SD/NVB) at age 16 mediated the association between testosterone level (ages 12-14) and SUD (age 22). In addition, SD/NVB mediated the association between ND and SUD. These findings suggest that development of SUD is influenced by androgen-dependent and neurobehavioral processes via a social motivational style characterized by SD/NVB. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Executive cognitive functioning, temperament, and antisocial behavior in conduct-disordered adolescent females.

The authors assessed whether low executive cognitive functioning (ECF) and a difficult temperament are related to aggressive and nonaggressive forms of antisocial behavior (ASB) in 249, 14–18-year-old, conduct-disordered females and controls. ECF was measured using neuropsychological tests; temperament was measured using the Dimensions of Temperament Survey—Revised; and ASB was assessed using psychiatric symptom counts for conduct disorder. The conduct-disordered females exhibited lower ECF capacity and a greater difficult temperament compared with the controls. The combined influence of low ECF and difficult temperament was significantly related to both forms of ASB. In comparison with low ECF, difficult temperament was more strongly related to nonaggressive ASB, whereas in comparison with difficult temperament, low ECF was more strongly related to aggressive ASB. Last, ECF mediated the relation between difficult temperament and aggressive ASB. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coarse-grained Molecular-level Analysis of Polyurea Properties and Shock-mitigation Potential

Several experimental investigations reported in the open literature clearly established that polyurea (PU), an elastic copolymer, has an unusually high ability to attenuate and disperse shock waves. This behavior of PU is normally attributed to its unique nanometer-scale two-phase microstructure consisting of (high glass-transition temperature, T _g) hydrogen-bonded discrete, hard domains dispersed within a (low T _g) contiguous soft matrix. However, details regarding the mechanism(s) responsible for the superior shock-wave mitigation capacity of PU are still elusive. In the present study, molecular-level computational methods and tools are used to help us identify and characterize these mechanism(s). Because the shock-wave front structure and propagation involve coordinated motion of a large number of atoms and nano-second to micro-second characteristic times, these phenomena cannot be readily analyzed using all-atom molecular-level modeling and simulation techniques. To overcome this problem, all-atom PU microstructure is coarse-grained by introducing larger particles (beads), which account for the collective degrees of freedom of the constituent atoms, the associated force-field functions determined and parameterized using all-atom computational results, and the resulting coarse-grained model analyzed using conventional molecular-level computational methods and tools. The results thus obtained revealed that a combination of different deformation mechanisms (primarily shock-induced ordering and crystallization of hard domains and coordinated shuffle-like lateral motion of the soft-matrix segments) is most likely responsible for the superior ability of PU to attenuate/disperse shock waves.     

Association between hyperactivity and executive cognitive functioning in childhood and substance use in early adolescence

OBJECTIVE: To determine whether deficient executive cognitive functioning (ECF) in association with high behavioral activity level comprise components of the liability to substance abuse. METHOD: A high-risk (HR) group having fathers with a lifetime DSM-III-R diagnosis of a psychoactive substance use disorder was compared with a low-average-risk (LAR) group whose fathers had neither psychoactive substance use disorder nor another adult Axis I psychiatric disorder. ECF and behavioral activity were measured using neuropsychological tests, activity monitor, diagnostic interview, and informant ratings when the subjects were 10 to 12 years of age. Alcohol, tobacco, and cannabis use were measured at 2-year follow-up. RESULTS: At baseline, the HR group had a significantly higher behavioral activity level and exhibited poorer performance on ECF tests than the LAR group. By early adolescence, HR subjects had a higher lifetime rate of tobacco and cannabis use and earlier age at onset of cannabis use. ECF capacity, but not behavioral activity level, predicted tobacco and cannabis use, total number of drugs ever tried, and severity of drug involvement. ECF accounted for additional variance beyond the effects of conduct problems on these outcomes. CONCLUSION: Whereas behavioral activity and ECF capacity in late childhood distinguishes HR from LAR youth, childhood ECF capacity is the more salient predictor of drug use in early adolescence.     

Association Among Parental Substance Use Disorder, P300 Amplitude, and Neurobehavioral Disinhibition in Preteen Boys at High Risk for Substance Use Disorder.

The P300 amplitude of the event-related potential as a mediator of the association between parental substance use disorder (SUD) and child's neurobehavioral disinhibition was assessed. The P300 amplitude was recorded using an oddball task in sons of fathers having either lifetime SUD (n = 105) or no psychiatric disorder (n = 160). Neurobehavioral disinhibition was assessed using measures of affect regulation, behavior control, and executive cognitive function. Parental SUD and child's P300 amplitude accounted for, respectively, 16.6% and 16.8% of neurobehavioral disinhibition variance. Controlling for parental and child psychopathology, an association between parental SUD and child's P300 amplitude was not observed. It was concluded that the P300 amplitude does not mediate the association between parental SUD and child's neurobehavioral disinhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental trajectory classes in substance use disorder etiology.

Three trajectory classes culminating in substance use disorder (SUD) were discerned in a longitudinal study of boys from ages 10-12 to 22 years. Neurobehavior disinhibition, parental SUD, socioeconomic status, and affiliation with deviant peers were measured at baseline. Approval of socially nonnormative behavior was measured at ages 10-12, 12-14, 16, and 19 years. Two high-risk trajectories, indicated by increasing approval of antisociality and progressive social maladjustment during adolescence (SUD rate = 72.7%) and stable high level of disturbance (SUD rate = 85%), were identified. Individual characteristics (neurobehavior disinhibition) in conjunction with contextual factors (low socioeconomic status, parental SUD, affiliation with deviant friends) promote approval of antisociality during adolescence and a high rate of SUD by young adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Altered motor control in chronic alcoholics.

Compared the performance of 48 male chronic alcoholic patients and 48 nonalcoholic medical patients on a test of motor control (turning a knob as slowly as possible) and other tasks (e.g., time estimation). Results show that alcoholics turned the knob significantly faster than nonalcoholics. The differences between groups were greatest when Ss performed with eyes closed. The difference in knob-turning can not be accounted for by performance on the other tasks; alcoholics showed visual-spatial difficulties, muscle weakness, hand tremor, and subjective-time overestimation. In addition, impaired control was found in both hands and on a slow line-drawing test. 2 possible neuropsychological explanations are advanced to account for the alcoholics' performance: (a) damage to the frontal-limbic diencephalic circuit resulted in disrupted inhibitory motor control, and (b) right hemisphere damage interfered with utilization of kinesthetic-proprioceptive information in the feedback control of motor behavior. (25 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)