Dissertations / Theses on the topic 'Impulsive aggression'

One of the most difficult and serious challenges facing the mental health professional is the prevention of suicide. Efficient prevention, however, depends on early detection of patients at risk for suicidal behaviour, which in turn depends on a better understanding of the predisposing factors. Over the last years, based on a large volume of data, it has become increasingly clear that subjects who commit suicide present high levels of impulsive and impulsive-aggressive behaviours.
In the first approach, we investigate whether levels of the impulsive aggressive diathesis were more important in suicide occurring at different life stages. In the second, we investigate whether levels of the diathesis predicted when during the course of major depressive disorder suicide occurs.
Family studies have consistently indicated that suicidal behaviour tends to cluster in families. However, relatives also present increased risk for psychiatric morbidity, and therefore, the critical question is whether or not the liability to suicidal behavior is given by the same predisposition to the coexistent psychiatric disorders.
Therefore, in the third study, we examined the independence of familial liability using a three group design. The relatives of deceased suicide probands who died in the context of a major depressive episode are compared to the relatives of living depressed subjects without a history of suicide and to the relatives of healthy controls screened for the absence of major depression and suicide.

Antisocial personality disorder (ASPD) is a condition characterized by elevated impulsive aggression and increased risk for criminal behaviour and incarceration. Deficient activity of the monoamine oxidase A (MAOA) gene is suggested to contribute to serotonergic system dysregulation strongly associated with impulsive aggression and ASPD. The potential contribution of epigenetic processes, which modulate gene expression without altering the underlying genomic code, towards the dysregulation of MAOA in ASPD is not yet understood.The current study aimed to elucidate the role of epigenetic processes in altered MAOA expression and serotonin regulation in a population of offenders with ASPD compared to healthy controls. Results suggest MAOA promoter hypermethylation contributes to downregulated gene expression and elevated whole-blood serotonin in offenders with ASPD. These results are consistent with prior literature suggesting MAOA and serotonergic dysregulation in antisocial populations. Further, our results offer the first evidence suggesting epigenetic mechanisms may contribute to MAOA dysregulation in antisocial offenders.
Le trouble de personnalité antisociale est une condition qui se caractérise par un niveau élevé d'agression impulsive ainsi qu'un risque accru de comportements criminels et d'incarcération. Il a été suggéré qu'une activation déficitaire du gène monoamine oxydase A (MAOA) contribuerait à une dysrégulation du système sérotogénique, qui est fortement associé à l'agression impulsive et au trouble de personnalité antisociale. La potentielle contribution des processus épigénétiques modulant l'expression génétique sans altérer le code génomique sous jacent dans la dysrégulation du MAOA chez les individus atteint du trouble de personnalité antisociale n'est pas encore comprise. L'étude suivante avait comme objectif d'élucider le rôle des processus épigénétiques dans l'altération de l'expression du MAOA et de la régulation de la sérotonine dans une population incarcérée avec un trouble de personnalité antisociale, lorsque comparés à des contrôles sains. Les résultats suggérent que le promoteur d'hyperméthylation MAOA contribue à une réduction de l'expression génétique et à un niveau élevé de sérotonine sanguin chez les incarcérés avec un trouble de personnalité antisociale. Ces résultats sont cohérents avec la littérature suggérant que la dysrégulation du MAOA et de la sérotonine est présente dans les populations antisociales. De plus, nos résultats représentent la première évidence suggérant que les méchanismes épigénétiques pourraient contribuer à la dysrégulation du MAOA chez les incarcérés avec un trouble de personnalité antisociale.Le trouble de personnalité antisociale est une condition qui se caractérise par un niveau élevé d'agression impulsive ainsi qu'un risque accru de comportements criminels et d'incarcération. Il a été suggéré qu'une activation déficitaire du gène monoamine oxydase A (MAOA) contribuerait à une dysrégulation du système sérotogénique, qui est fortement associé à l'agression impulsive et au trouble de personnalité antisociale. La potentielle contribution des processus épigénétiques modulant l'expression génétique sans altérer le code génomique sous jacent dans la dysrégulation du MAOA chez les individus atteint du trouble de personnalité antisociale n'est pas encore comprise. L'étude suivante avait comme objectif d'élucider le rôle des processus épigénétiques dans l'altération de l'expression du MAOA et de la régulation de la sérotonine dans une population incarcérée avec un trouble de personnalité antisociale, lorsque comparés à des contrôles sains. Les résultats suggérent que le promoteur d'hyperméthylation MAOA contribue à une réduction de l'expression génétique et à un niveau élevé de sérotonine sanguin chez les incarcérés avec un trouble de personnalité antisociale. Ces résultats sont cohérents avec la littérature suggérant que la dysrégulation du MAOA et de la sérotonine est présente dans les populations antisociales. De plus, nos résultats représentent la première évidence suggérant que les méchanismes épigénétiques pourraient contribuer à la dysrégulation du MAOA chez les incarcérés avec un trouble de personnalité antisociale.

Impulsivity and aggression have been shown to be important behavioral correlates of suicide. Neurobiological and genetic studies, mostly focusing on the serotonergic system, have demonstrated that these behaviors not only have clinical implications in suicide but also play an important biological role in increasing suicide risk. It remains unclear, however, how impulsivity and aggression might mediate suicide risk. The first study presented here was carried out to investigate clinical, behavioral and psychosocial correlates of impulsivity in suicide completers. Impulsive suicides were characterized by a greater psychiatric comorbidity as well as increased levels of aggression, and were more likely to be affected by negative life events. In a separate study, the effect of genetic variants of the 5-HT1B gene on impulsive aggressive behaviors (IABs) in suicide, as well as their contribution to overall suicide risk, was investigated. One 5-HT1B promoter variant significantly influenced levels of aggressive behaviors in suicide completers, suggesting that aggression plays a role as an intermediate phenotype that increases propensity to suicide. Both studies highlight the importance of the role of IABs in mediating suicide at both clinical and biological levels.

A wealth of data supports the hypothesis that the neurotransmitter serotonin regulates the intake of ethanol, and is involved in the development of alcoholism in humans. Reduced functioning of the serotonergic system hypothetically increases alcohol intake in both animals and humans. In this thesis, it was proposed that the effect of lowered serotonergic function on alcohol intake is mediated by an increase in disinhibition. The hypothesis that lowered serotonin increases disinhibition was tested in separate groups of individuals at high risk for the development of psychopathology: nonalcoholic young men with a strong family history of paternal alcoholism, and adolescent men with previous histories of physically aggressive behavior. Lowered serotonergic synthesis (and thus presumably function) was experimentally induced through a transient dietary reduction in the availability of the amino add precursor of serotonin, tryptophan. Disinhibition was quantified using a go/no-go task previously shown to characterize psychopaths and children with attention deficit hyperactivity disorder as disinhibited. In the first study, acute tryptophan depletion had no effect on aggressive responding on a modified competitive reaction time aggression task, but increased disinhibition in young men at risk for alcoholism. This effect was independent of the tryptophan depletion-induced mood alterations. The effect tryptophan depletion on disinhibition was not replicated in the second study with previously aggressive adolescent men. A number of explanations for this were posited, including the presence of a ceiling effect. An association between disinhibition and executive functioning (cognitive abilities associated with proper functioning of the prefrontal cortex, such as working memory, planning abilities) was demonstrated in the second study. In a third preliminary study, no association between disinhibition on the go/no-go task and allelic polymorphisms of the dopamine D4 receptor

Objectives: There is evidence that childhood traumatic brain injury (TBI) is associated with increased risk of offending and violent crime. This study aimed to explore associations between TBI in a group of delinquent and vulnerable young people (VYP) at risk of offending, and facial emotion recognition (FER) abilities, inhibition control (Stop-IT) and self-reported reactive-proactive aggression (RPQ). Methods: There were two studies. The first study used a cross sectional between group design to compare 45 VYP (with and without TBI) and a control group of 59 students on FER task measuring emotion recognition accuracy of six basic emotions. The second study examined differences between TBI and non-TBI groups in the VYP sample (N=21) on a Stop-IT task, FER accuracy and self-reported reactive-proactive aggression. Results: A history of TBI was reported by 60% of the VYP group (48.9% with loss of consciousness [LoC]), whereas 30% of the control group reported a history of TBI (25.4% with LoC). The VYP group (with and without TBI) demonstrated a similar pattern of reduced overall FER accuracy that was significantly different to the control group. Compared to the control group, The VYP groups (with and without TBI) were less accurate on recognising anger, disgust, sadness and surprise, but not happy and fear. There were no significant differences between the TBI- and non-TBI groups. The second study did not find any significant differences between the TBI and non-TBI groups on overall FER accuracy, Stop-IT performance, and RPQ scores. There were also no significant associations between these measures. Conclusions: Future research requires larger samples that enable investigating the association between different severity of TBI, FER and inhibition control ability. Better and more youth-friendly measures are also needed.

Abstract Conduct disorder (CD) among girls is a common but seldom studied psychiatric disorder. The aim of this study was to examine risk factors for CD, the factor structure of CD symptoms, suicidal behaviour, comorbid disorders and nicotine dependence of adolescent girls with CD in an inpatient sample in Northern Finland. The study subjects were 508 12- to 17-year-old inpatients treated in an acute psychiatric ward, Unit 70, at Oulu University Hospital between April 2001 and March 2006. These adolescents were interviewed using the Schedule for Affective Disorder and Schizophrenia for School-Age Children Present and Lifetime (K-SADS-PL) to obtain psychiatric diagnoses according to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). In addition, the European Addiction Severity Index (EuropASI) was used to obtain information on somatic health, family situation and delinquency. From the data collected, 63 girls and 92 boys fulfilled the criteria for current DSM-IV-diagnosed conduct disorder. It was observed that, although the number of symptoms and severity of CD was lower among girls compared to boys, the level of functioning was lowered to the same degree. Physical abuse increased the risk for violent CD, and living apart from at least one biological parent increased the risk for both violent and non-violent CD among girls. The results of this study also suggest a gender difference in the factor structure and developmental model of CD. Alcohol dependence increased the risk for suicide attempt and self-mutilation almost fourfold among girls with CD. Girls with CD had more comorbid affective and anxiety disorders than boys. Girls with CD also had more self-reported allergies. Finally, the number of CD symptoms was positively correlated with the level of nicotine dependence (ND) among both girls and boys, and a gender difference was found in the correlation between symptom subscales and the level of ND. The findings suggest that gender differences exist in conduct disorder. Special attention should be paid to the prevention, identification and treatment of CD among girls. It seems that, among girls with CD, the well-being of primary family is important in prevention. Alcohol dependence and depression in girls with CD should be treated with special care. DSM-IV might not always be sensitive enough to diagnose CD among girls, and this should be considered when behavioural symptoms are evaluated in girls
Tiivistelmä Tyttöjen käytöshäiriö on vähän tutkittu mutta yleinen psykiatrinen häiriö. Tässä tutkimuksessa analysoitiin tyttöjen käytöshäiriön riskitekijöitä, oireiden faktorirakennetta, käytöshäiriöisten itsetuhoisuutta, samanaikaista psykiatrista ja somaattista sairastavuutta sekä nikotiiniriippuvuutta psykiatrisessa osastohoidossa olleiden alaikäisten nuorten keskuudessa. Tutkimusaineistoon kuului 508 12–17-vuotiasta nuorta, jotka olivat hoidossa psykiatrisella akuuttihoito-osastolla Oulun yliopistollisessa sairaalassa 1.4.2001–31.3.2006 välisenä aikana. Nuoret haasteteltiin käyttämällä puolistrukturoitua Schedule for Affective Disorder and Schizophrenia for School-Age Children Present and Lifetime (K-SADS-PL) -haastattelua, jonka avulla määritettiin nuorten psykiatriset diagnoosit Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) -diagnoosiluokituksen mukaisesti. Lisäksi potilaat haastateltiin European Addiction Severity Index (EuropASI) -haastattelulla, josta saatiin tietoa fyysisestä terveydentilasta, perhetilanteesta ja rikollisuudesta. Aineiston nuorista 63 tyttöä ja 92 poikaa täyttivät käytöshäiriön kriteerit. Tämä tutkimus osoitti, että vaikka nykyisten DSM-IV-kriteerien perusteella tytöillä käytöshäiriön vaikeusaste oli aiempien tutkimusten tapaan poikia alhaisempi ja oireiden määrä vähäisempi, oli tyttöjen toimintakyky silti yhtä huono kuin poikien. Fyysinen perheväkivalta lisäsi tyttöjen riskiä väkivaltaiseen käytöshäiriöön ja asuminen erossa vähintään yhdestä biologisesta vanhemmasta lisäsi riskiä sekä väkivaltaiseen että ei-väkivaltaiseen käytöshäiriöön. Käytöshäiriöoireiden faktorianalyysi osoitti, että tytöillä ja pojilla oli eroa oireiden faktorirakenteessa eikä tyttöjen oireiden jako selkeästi noudattanut Loeberin esittämää polkumallia. Alkoholiriippuvuus lisäsi käytöshäiriöisillä tytöillä riskiä itsemurhan yrittämiseen ja itsensä vahingoittamiseen lähes 4-kertaiseksi. Käytöshäiriöisillä tytöillä oli poikia enemmän mieliala- ja ahdistushäiriöitä samanaikaisina psykiatrisina häiriöinä. Somaattisista häiriöistä käytöshäiriöiset tytöt raportoivat poikia enemmän allergioita. Käytöshäiriön oireiden määrä oli yhteydessä sekä tytöillä että pojilla nikotiiniriippuvuuden voimakkuuteen. Tyttöjen ja poikien välillä oli eroa nikotiiniriippuvuuteen korreloivissa oireryhmissä. Tämän tutkimuksen tulosten perusteella tyttöjen ja poikien käytöshäiriöllä on eroavaisuuksia. Tyttöjen käytöshäiriön ennaltaehkäisyyn, tunnistamiseen ja hoitoon tulee kiinnittää erityistä huomiota. Primaariperheen hyvinvointi näyttäisi olevan tärkeää ennaltaehkäisyssä. Käytöshäiriöisen tytön hoidossa tulee kiinnittää erityinen huomio alkoholin käyttöön sekä depression hoitoon itsetuhoisuuden ehkäisemiseksi. DSM-IV ei ehkä nykyisellään ole riittävän herkkä työkalu tyttöjen käytöshäiriön diagnosoimiseksi, ja tähän tulisi kiinnittää huomiota kun käyttäytymisellään oireilevia tyttöjä hoidetaan

Aggression studies in laboratory animals have largely focused on natural species-specific forms of aggression that poorly reflect pathological types of aggression in humans. The primary goal of this dissertation was to identify and characterize a subtype of aggression in support for a congenital animal model of reactive/impulsive-aggression in humans. Experiments using novel second-by-second analyses to investigate for individual differences in aggression and impulsive choice showed detailed quantitative and qualitative differences, and identified a convergence of behaviors to one distinct impulsive-aggressive profile in high-attack frequency (HAF) hamsters. As aggression and impulsivity widely implicate the serotonin (5HT) system, and previous studies have similarly characterized the neural control of aggression in hamsters, it was hypothesized that impulsive-aggression in HAF individuals was associated to common neurobiology. While 5HT does play a role, immunocytochemical experiments and pharmacological manipulations showed a distinct neurobiological profile of decreased 5HT availability, increased densities of 5HT1A and 5HT3 receptor subtypes, and drastically differential and opposite phenotypic-dependent reactivity to 5HT3 receptor blockade. Moreover, the current studies also showed that while 5HT3 receptor activity has broad effects, attenuating all behavioral aspects of the impulsive-aggressive phenotype (i.e. aggression, repetitiveness, fragmentation, and impulsive choice), 5HT1A receptor activity seems to have more limited effects. Additional retrospective studies investigated developmental and etiological differences between the phenotypes. HAF adults were associated with low agonistic activity in early puberty and an early emergence of impulsivity-related characteristics. These data indicate a differential developmental trajectory of behavior and accelerated maturation, consisting of a lack of play fighting during early puberty. The HAF phenotype was additionally associated with paternal, but not maternal influence, suggesting male genetic contribution. Together, these data support a congenital animal model that better reflects reactive forms of aggression in humans through the behavioral, neurobiological, and developmental characterization of HAF hamsters described herein. These data have pre-clinical and clinical significance and can be applied to diagnostic and preventative measures, as they illustrate the importance of distinguishing predictions about extreme fringe populations from that of normal populations, point towards more specific pharmacological therapeutic applications, identify early predictive behaviors of impulsive-aggression, and suggest heritability.
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博士
國立臺灣大學
心理學研究所
106
Intimate partner violence (IPV) not only destroys intimacy and trust in the relationship, but also harms the harmony of the family. Children’s witnessing of intimate partner violence has adverse effect on their mental health, and may contribute as a risk factor to the intergenerational transmission of violence and future intimate partner violence. The purpose of the present research was three-fold: 1) After adjusting for social desirability response bias, tested the possible subtypes of male offenders of intimate partner violence (IPV), namely, predominantly impulsive aggression and predominantly premeditated aggression; 2) tested our proposed impulsive aggression offending process model among male inmates of IPV; and 3) examined whether the risk factors associated with impulsive aggressive offending were also predictive of recidivism among male inmates of IPV. Using purposive sampling, 186 male inmates of IPV were recruited. Data collection methods included semi-structured interview, criminal history review, and self-reports. The results showed that the construct validity of the Impulsive/Premeditated Aggression Scales (IPAS) was confirmed. The aggression of most inmates in the present sample was characterized as predominately impulsive in nature (90%). As to the research purpose 2, it showed that the more severe IPV inmates’ alcohol consumption problems, the higher the likelihood of impulsive aggression. Besides, levels of negative sense of control also had positive effects on impulsive aggression. Finally, regarding the research purpose 3, it revealed that when violation of protection order for the index offense, drop-out from community treatment and 5-year recidivism of intimate partner violence were taken into account, the predictive ability of recidivism of the impulsive aggression subtype of IPV reached almost eighty percent (77.4%) accuracy. Hence, according to the findings of this research, we recommend that in future interventions for domestic violence, treatment approaches could be developed based on reducing IPV inmates’ negative sense of control and alcohol consumption problems. Further, this research revealed high social desirability in inmates of IPV, indicating the need to establish a trusting therapeutic relationship. The duration and termination of treatment also need to be adjusted according to the degree of rapport and trustworthiness established as well as the effectiveness of the treatment.

碩士
嘉南藥理大學
保健營養系
103
According to the literature, the individuals who had insufficient intakes of fruits and vegetables, and preferred to eat high-calorie fried foods and sugar-sweetened beverages are more prone to have unstable emotional control. The purpose of the study is to investigate the associations of the dietary intake related factors to impulsive personality and aggressive behavior among the elementary school children. A total of 146 5th- & 6th-grade students (81 boys, 55.5%; 65 girls,44.5% ) were recruited, by convenience sampling. Self-reported questionnaires of students and parents were employed as measuring tools. The questionnaire included four parts: dietary intake habits, food preferences, impulsive personality and aggressive behavior. The results showed that the dietary intake habits positively correlated with food preferences (r=0.608, p=0.000),and the impulsive personality positively correlated with the aggressive behavior(r=0.718, p=0.000).The dietary intake habits and food preferences had negative correlation with the impulsive personality (r= - 0.370, p=0.000 and r= - 0.396, p=0.000, respectively). The dietary intake habits had significant differences with the overall impulsive personality (F＝5.56﹐p＝0.005). The food preferences had significant differences with the overall impulsive personality (F＝8.46﹐p＝0.000) . The impulsivity was significantly different from the overall dietary intake habits (F＝11.06﹐p＝0.000). The impulsivity was significantly different from the overall the food preferences (F＝11.85﹐p＝0.000).The impulsive personality had significant differences with the dietary intake habit of eating at least three dishes vegetable each day (F＝7.48﹐p＝0.001). The impulsive personality had significant differences with the dietary intake habit of eating at least two servings of fruit each day (F＝6.29﹐p＝0.002). The impulsive personality had significant differences with the dietary intake habit of eating dark green vegetable (F＝8.14﹐p＝0.000). The impulsive personality had significant differences with the dietary intake habit of eating such as apples and kiwi fruit (F＝6.52﹐p＝0.002). The impulsive personality had significant differences with the dietary intake habit of eating foods such as pumpkin seeds and walnuts (F＝8.79﹐p＝0.000). The impulsivity also had differences from the preferences of eating fish (F＝5.06﹐p＝0.008), seafood (F＝4.32﹐p＝0.015), soy foods (F＝4.49﹐p＝0.013), fast foods (F＝6.08﹐p＝0.003), and drinking sugar-sweetened beverages (F＝7.12﹐p＝0.001). The impulsivity was significantly different from the dietary intake habits of vegetables and the overall dietary intake habits. The aggressive behavior was significant different from the dietary intake habits of eating at least three dishes vegetable each day (F＝3.71﹐p＝0.027). The aggressive behavior had significant differences with the food preferences of eating fast foods (F＝3.52﹐p＝0.032), drinking sugar-sweetened beverages (F＝7.28﹐p＝0.001), and the overall food preferences (F＝3.66﹐p＝0.028). The study suggested that it might improve the impulsive personality and aggressive behavior of school children by educating them to reducing their preferences of some high-calorie and low-nutrient density foods including fast foods, and sugar-sweetened beverages, which considered to have some health concerns, as well as eating at least three dishes vegetable each day. Keywords: elementary school students, dietary intake habit, food preference, impulsive personality, aggressive behavior