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Results for “Impulsive Behavior”

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PubMed2005

A least-squares parameter estimation algorithm for switched hammerstein systems with applications to the VOR.

A "Multimode" or "switched" system is one that switches between various modes of operation. When a switch occurs from one mode to another, a discontinuity may result followed by a smooth evolution under the new regime. Characterizing the switching behavior of these systems is not well understood and, therefore, identification of multimode systems typically requires a preprocessing step to classify the observed data according to a mode of operation. A further consequence of the switched nature of these systems is that data available for parameter estimation of any subsystem may be inadequate. As such, identification and parameter estimation of multimode systems remains an unresolved problem. In this paper, we 1) show that the NARMAX model structure can be used to describe the impulsive-smooth behavior of switched systems, 2) propose a modified extended least squares (MELS) algorithm to estimate the coefficients of such models, and 3) demonstrate its applicability to simulated and real data from the Vestibulo-Ocular Reflex (VOR). The approach will also allow the identification of other nonlinear bio-systems, suspected of containing "hard" nonlinearities.

Algorithms↗

PubMed2000

Progression of consequences among heavy-drinking college students.

Among a sample of 180 male and 226 female undergraduates, 84.2% reported a heavy drinking episode (5+ drinks for men, 4+ for women) within the previous 90 days. Principal-components analysis revealed 3 alcohol-related problem factors among the heavy drinkers (Careless Behavior, Risky/Reckless Behavior, and Authority Problems). Nearly all heavy drinkers experienced a careless behavior that was due to drinking (92.7%), and many reported a risky/reckless behavior (60.2%), yet only one third (33.9%) experienced an authority problem. Guttman scaling procedures revealed a progression from Careless Behavior to Reckless/Risky Behavior to an Authority Problem. Heavy drinkers with an authority problem drank more frequently, consumed more when drinking, endorsed more alcohol expectancies, and reported earlier ages of initial and regular drinking than other groups.

Adult↗

PubMed1983

Strategy production by young Down syndrome children.

A sample of young Down syndrome children was compared with three nonretarded samples, one equated for developmental age, one for language age, and one for ability to delay touching an attractive but prohibited stimulus. Results indicated that Down syndrome children were significantly less able to delay touching than were nonretarded children of similar developmental or language level; in addition, several kinds of within-task strategy behavior were identified that facilitated performance of the nonretarded children. These included turning attention, verbal and nonverbal, away from the stimulus. Implications for assessment were discussed, as were ramifications for the question of "developmental vs. difference" conceptualizations of mental retardation.

Child Development↗

PubMed1982

Coincident timing behavior of young mentally retarded workers under varying conditions of target velocity and exposure.

The degree to which response complexity affects the ability of moderately mentally retarded adults to perform on a coincident timing task was examined. In Experiment 1 subjects were required to depress a key to estimate accurately the arrival of a moving target at a predetermined coincident point. Analyses of both constant and variable error scores suggested that subjects had difficulty inhibiting their responses and that an optimal exposure distance for the task existed. In Experiment 2 subjects were required to make a movement response to the target. Subjects made more constant errors in this experiment but improved when provided maximum target preview. These mixed findings are discussed in terms of subjects' impulsivity and their sensitivity to the characteristics of the display.

Adult↗

PubMed2006

Gender and risk factors for suicide: evidence for heterogeneity in predisposing mechanisms in a psychological autopsy study.

OBJECTIVE: It is unclear whether clinical and behavioral suicide risk factors, identified primarily among men, can be extended to women. We therefore explored sex differences in psychopathology and personality variants among suicide completers. METHOD: Using the psychological autopsy method, we compared personality variants and the prevalence of psychopathology as a function of sex among 351 consecutive suicides in a large, urban community. Psychiatric diagnoses were obtained using the Structured Clinical Interview for DSM-IV-TR Axis I Disorders and the Structured Clinical Interview for DSM-IV Axis II Personality Disorders, and measures of impulsive aggression, temperament, and character were administered. Subsequently, we carried out secondary analyses between male and female suicides matched 2:1 for age, current depression, and number of lifetime depressive episodes. The study was conducted from late 2000 to 2005. RESULTS: Females were less likely to meet criteria for current and lifetime alcohol abuse, but those who did were less likely than males to have concurrent depression. On average, females were less impulsive, yet similar proportions of males and females were highly impulsive and impulsivity was associated with alcohol abuse irrespective of gender. Females were more likely to meet criteria for lifetime anxiety disorders; these were associated with nonviolent suicide methods, irrespective of gender. CONCLUSIONS: Despite a lower prevalence among females, high levels of impulsivity and alcohol abuse appear to be valid risk factors for both sexes. Researchers should focus on females for the identification of other suicide mediators.

Adult↗

PubMed1997

Serotonergic function and self-injurious behavior in personality disorder patients.

Self-directed aggression, whether in the form of non-suicidal self-mutilation or suicidal behavior, is a prominent feature of personality disorders. We hypothesized that self-injurious behavior, like suicidal behavior, represents a form of self-directed aggression, and may, like suicidal behavior and impulsive aggression, be associated with a decrease in central serotonin function in personality disorder patients. Ninety-seven patients with DSM-III personality disorder underwent D,L-fenfluramine challenge as an assessment of serotonergic activity. Patients with a history of self-mutilation or suicide had blunted prolactin and cortisol responses to D,L-fenfluramine compared to those with neither, and those with both had the most blunted responses to fenfluramine. These data raise the possibility that the central 5-HT abnormality, previously associated with suicidal behavior, may be associated with self-directed violence and not necessarily specifically with suicidal intent.

Adult↗

PubMed2004

A call for research on planned vs. unplanned suicidal behavior.

Unplanned acts of suicidal behavior involve little preparation or forethought whereas planned acts may be carefully conceived and implemented. Planned acts are associated with greater depression, hopelessness, and lethality, but there are meager data on other factors associated with planning. The prevention of planned and unplanned acts may require different strategies, but in either case improved knowledge is required to tailor prevention efforts. Improved knowledge can be facilitated by the acceleration of validation studies on assessments of planning, taking steps to avoid the conflation of assessments of planning with measurements of psychopathology such as impulsivity, and the use of controlled research designs.

Depression↗

PubMed1994

[Open self-injury behavior].

Patients showing self-mutilation behavior are supposed to be a new group of problematic patients in psychiatric institutions. The theme is presented from an anthropological, phenomenological, nosological and etiological point of view. To understand the genesis we apply biological, behavioristic and psychoanalytical concepts. Finally, using this background therapeutic ideas are discussed.

Adolescent↗

PubMed2006

Correlations among measures of executive function and positive psychological attributes in college students.

Executive functions are cognitive abilities that allow for more goal-oriented and autonomous behavior. The authors examined the relationship between self-rated executive functions and 3 positive personality attributes (satisfaction with life, gratitude, and forgiveness) in a nonclinical community sample. The authors used self-report scales (Executive Function Index, Heartland Forgiveness Scale "other" subscale, Satisfaction With Life Scale, and the Gratitude Questionnaire) to examine how executive functions related to the positive psychology attributes. After controlling for age, sex, and formal education, positive relationships emerged among gratitude, satisfaction, and executive function scales of motivational drive, empathy, and strategic planning. However, an inverse relationship emerged between impulse control and forgiveness, perhaps relating to cautiousness and suggesting finer distinctions between adaptive and maladaptive forms of forgiveness. These findings suggest common psychological and neurobiological substrates for executive functions and positive psychology attributes, warranting further, more direct biobehavioral research.

Adolescent↗

PubMed2000

Executive processing and attention deficit hyperactivity disorder: an application of the supervisory attentional system.

Children with attention deficit hyperactivity disorder (ADHD) display many behaviors consistent with an underlying deficit in executive processes. This study examines Norman and Shallice's (1986) supervisory attentional system (SAS) as an approximation of executive functioning thought to be impaired in ADHD. Fifteen ADHD children were compared to a clinical control sample of learning disabled (LD) children and control children matched for age, gender, and IQ on a series of tasks designed to tap the functions of the SAS. The tasks assessed either the inhibition of a strongly triggered response (Star Counting Test, Hayling Sentence Completion Test, and the Random Generation Test) or impulsive responding in the absence of strong trigger-schema contingencies (Brixton Spatial Anticipation Test). Analyses revealed that the ADHD group was significantly impaired, in comparison to the LD and control groups, on tasks requiring the inhibition of a strongly triggered response. Further support for the fractionation of the SAS is provided by the differential performance of the groups on these tasks.

Arousal↗

PubMed2006

Tourette's syndrome (TS): cognitive performance in adults with uncomplicated TS.

Tourette's syndrome (TS) is a neurodevelopmental disorder associated with frontostriatal dysfunction. The extent of any cognitive impairment associated with uncomplicated TS is unclear, as comorbid psychiatric symptomatology is thought to contribute to cognitive deficits. Previous studies have found evidence of mild performance deficits, most commonly on tasks that involve inhibitory processes. The present study evaluated this in carefully screened adult participants with TS. The findings showed the TS group to perform more poorly on one test involving behavioral inhibition (sentence completion), but did not provide strong support for an interpretation based solely on inhibitory deficits, and there was no evidence of impairment on another behavioral inhibition task (flanker test). There were also no differences between the groups on tasks involving working memory (n-back), task switching, or object alternation learning. The findings provide further evidence that uncomplicated TS is associated with only mild, circumscribed impairment. The nature of any impairment is discussed.

Adult↗

PubMed2000

Violent thoughts and violent behavior following hospitalization for mental disorder.

Using a standardized schedule of questions, this study examined (a) the prevalence of self-report of violent thoughts by patients hospitalized for mental disorders compared with nonpatients, (b) the persistence of violent thoughts after discharge, and (c) the relation between patients' violent thoughts while hospitalized and violent acts within 20 weeks after hospital discharge. About 1/3 of the patients reported thoughts of violence while hospitalized, more than twice the proportion found among nonpatients. Reporting violent thoughts in hospital was significantly related to engaging in violent acts within 20 weeks after discharge for non-White patients, patients without major mental disorder but with substance abuse diagnoses, patients with high symptom severity, and patients whose reports of violent thoughts persisted after discharge. Reporting violent thoughts was significantly related to measures of psychopathy, anger, and impulsiveness.

Adult↗

PubMed2005

Differential effects of past-year stimulant and sedative drug use on alcohol-related aggression.

The goals of this study were to determine the effects of past-year stimulant and sedative drug use on alcohol-related aggression and to examine whether the relation between stimulant drug use and intoxicated aggression is better accounted for by behavioral disinhibition. Participants were 330 healthy social drinkers (164 men and 166 women) between 21 and 35 years of age. Past-year stimulant and sedative use and behavioral disinhibition were assessed via self-report questionnaires. Following the consumption of either an alcohol or a placebo beverage, participants were tested on a modified version of the Taylor Aggression Paradigm [Taylor, S. (1967). Aggressive behavior and physiological arousal as a function of provocation and the tendency to inhibit aggression. Journal of Personality, 35, 297-310] in which mild electric shocks were received from, and administered to, a fictitious opponent. Aggressive behavior was operationalized as the shock intensities administered to the fictitious opponent under conditions of low and high provocation. Results indicated that alcohol significantly strengthened the relation between stimulant drug use and aggression, but only among men. Behavioral disinhibition did not account for this effect. Regardless of past-year drug use, alcohol did not facilitate aggression among women. The present findings suggest that stimulant drug use may be a risk factor for intoxicated aggression for men. However, the underlying mechanisms accounting for this effect remain unclear.

Adult↗

PubMed2004

Coping with distress by eating or drinking: role of trait urgency and expectancies.

The authors propose that trait urgency (the tendency to act rashly when distressed) is a risk factor for both alcohol abuse and bulimic symptoms, that disorder-specific expectancies influence whether one engages in one behavior or the other, and that expectancies moderate urgency's influence on those behaviors. Cross-sectional findings were consistent with the model. Problems from alcohol use were comorbid with binge eating and purging. Trait urgency was associated with both behaviors. Alcohol expectancies were associated with drinking levels and with problem drinking, but not with eating. Eating expectancies were associated with binge eating, but not with alcohol use or problems. Urgency's effect on binge eating was moderated by expectancies, but its effect on alcohol use and problem drinking was not.

Adolescent↗

PubMed1996

L-Deprenyl augmentation of fluoxetine in a patient with Huntington's disease.

Fluoxetine and L-deprenyl were prescribed concurrently in a 19-year-old female with Huntington's disease. The patient showed significant affective, behavioral, and motoric improvements and there was no adverse effect resulting from this combination. Concomitant use of L-deprenyl in low doses and fluoxetine may be safe and beneficial in certain clinical situations, although further study is needed.

Adult↗

PubMed2005

Are nonpharmacological induced rewards related to anhedonia? A study among skydivers.

It is well-known that persons with a drug addiction experience feelings of anhedonia during "normal" daily activities. It has been proposed that these symptoms of anhedonia are the result of direct pharmacological influences of drugs on the dopamine system. To test the assumption that nonpharmacological processes are also involved in anhedonia, we studied anhedonic symptoms in skydivers who regularly expose themselves to thrillful extreme sport activity and then experience intense hedonic feelings. A group of skydivers completed anhedonia scales and their scores were compared to a control group (a group of rowers). The main finding of the present study was that subjects who engage in the high-risk activity of skydiving, experienced more anhedonic symptoms than subjects who do not engage in such an extreme sport, but rather prefer a low-risk activity like rowing. This finding supports the notion that skydiving has similarities with addictive behaviors and that frequent exposure to "natural high" experiences is related to anhedonia. This suggests that the negative emotional state as observed in drug users may not be exclusively the results of exogenous psychopharmacological effects, but might also result from psychological mechanisms that are partly responsible for these anhedonic feelings.

Adult↗

PubMed2006

Efficacy and tolerability of OROS methylphenidate in Korean children with attention-deficit/hyperactivity disorder.

This study evaluated the efficacy and tolerability in the initiation treatment of Concerta (OROS methylphenidate HCl) in Korean children with Attention-Deficit/Hyperactivity Disorder (AD/HD). One hundred and nineteen children with AD/HD were entered into a multi-center, open-label, four-week trial. The dosage of Concerta was adjusted by the investigators based on symptoms and safety assessments performed on a weekly basis. The safety of the drug and its efficacy for attention, behavior, and cognitive function were assessed. The primary outcome measures for efficacy were the Parent and Teacher IOWA Conners Rating Scales, Peer Interaction Items, and the Clinical Global Impression Scale. Cognitive tests (Continuous Performance Test, Matched Familiar Figure Test, Verbal Fluency Test, and Trail Making Test) were included as the secondary outcome measures. In most participants, OROS methylphenidate was well tolerated. There were significant improvements in attention, behavior, and function as measured by parents, teachers, and investigators. The benefit of the initiation of OROS methylphenidate in children with AD/HD was shown on the cognitive tests as well. These data provide support for the benefit of the once-daily methylphenidate preparation, Concerta in the treatment of Korean children with AD/HD. Children were initiated safely in this short-term trial, and its effectiveness was evident in the behavioral, as well as neuropsychological measurements.

Adolescent↗

PubMed2000

Gambling problems in substance abusers are associated with increased sexual risk behaviors.

OBJECTIVES: This study evaluated the association between gambling problems and HIV risk behaviors in substance abusers. PARTICIPANTS AND SETTING: One hundred and thirty-four substance abusers were recruited from advertisements placed in newspapers and at social service agencies. INTERVENTION: Gambling problems were assessed using the South Oaks Gambling Screen (SOGS). The Addiction Severity Index evaluated drug and psychosocial problems, and the HIV Risk Behavior Scale assessed risk behaviors. FINDINGS: Based on SOGS scores, 24% (n = 31) of substance abusers evidenced probable pathological gambling. Problem gambling substance abusers were more likely to be male than non-problem gamblers, but no other differences in demographic characteristics or drug use variables were noted. Compared to non-problem gamblers, problem gamblers reported more sex partners and less frequent use of condoms with casual and paid sex partners. Stepwise logistic regression confirmed the association between severity of gambling problems and more risky sexual behaviors; higher SOGS scores predicted having more than 50 sex partners, exchanging sex for drugs/money, and engaging in anal intercourse (p < 0.05). Participants with gambling problems were also less knowledgeable about HIV transmission. CONCLUSIONS: These data suggest that gambling problems may be a risk factor for contracting HIV. Increased efforts are needed to screen for and treat gambling problems among substance abusers.

Adult↗