Neurobiologic function and temperament in subjects with personality disorders

BACKGROUND

Personality traits have been hypothesized to involve specific neurotransmitter systems. In order to test this model, the relationship between the responses to serotonergic and noradrenergic probes, central cerebrospinal fluid (CSF) measures of monoamine neurotransmitters and the Tridimensional Personality Questionnaire (TPQ) were evaluated in a cohort of personality disorder subjects.

METHODS

A total of 142 patients meeting at least one personality disorder (meeting Diagnostic and Statistical Manual of Mental Disorders, Third Edition-Revised criteria) participated in these studies. The prolactin response to fenfluramine (a measure of serotonin function) was obtained for 110 subjects; growth hormone response to clonidine (a measure of noradrenergic function) was obtained for 77 subjects, while homovanillic acid (HVA) at baseline, an index of dopaminergic function, was available for 103 subjects. Measures of central neurotransmitter function (dopaminergic, serotonergic, and noradrenergic: HVA, 5-hydroxyindolacetic acid, and 3-methoxy-4-hydroxyphenylglycol, respectively) were available for 36 subjects. Separate regression analyses utilizing each of the hypothesized associations, where the TPQ total scores were used as the dependent measures and the biologic indices were the independent measures were conducted. Exploratory correlational analyses between these biologic measures and the four dimensions of the TPQ (and its subscales) were also conducted. (Correlations are reported if they would remain significant at P<.01 level after Bonferroni correction for multiple comparisons across the six neuroendocrine measures).

RESULTS

In the regression analyses, there was a trend association between CSF and plasma HVA in predicting novelty-seeking (P<.07). No other significant associations were found in the other three measures. Regarding the individual correlational analyses, the persistence scale of the TPQ was significantly positively correlated with the growth hormone response to clonidine (r=.30, P<.008). The sentimentality subscale (reward dependence) was positively correlated with CSF 5-hydroxyindolacetic acid (r=0.45, P<.001), while the attachment subscale (also reward dependence) was correlated with CSF 3-methoxy-4-hydroxyphenylglycol (r=0.49, P<.002).

CONCLUSION

Limited support was provided for a relationship between monoamines, particularly dopamine and novelty-seeking as well as norepinephrine and reward dependence but other hypothesized relationships were not supported by these measures.

Norepinephrine function in personality disorder: plasma free MHPG correlates inversely with life history of aggression

OBJECTIVE

Clinical and pre-clinical data suggest the possibility of a facilitory role for norepinephrine (NE) in impulsive-aggressive behavior. While clinical studies have focused on putative central measures of NE activity, few studies have been published using peripheral measures. In this study, the relationship between plasma free NE metabolite, plasma free 3-methoxy-4-hydroxyphenylglycol (pMHPG), and impulsive aggression was explored in subjects with personality disorder.

METHODS

Subjects were 30 male subjects with personality disorder in whom basal plasma free MHPG concentrations were obtained. Aggression was assessed using the Life History of Aggression (LHA) assessment and the Buss-Durkee Aggression scales; impulsivity was assessed using the Barratt Impulsiveness and the Eysenck Personality Questionnaire Impulsivity scales.

RESULTS

A significant inverse correlation was found between LHA-Aggression and pMHPG in these subjects. Correlations with other behavioral measures were not statistically significant. pMHPG was significantly lower among subjects with borderline personality disorder but not significantly lower after controlling for LHA-Aggression scores.

CONCLUSION

These data suggest that pMHPG is inversely correlated with life history of aggression in subjects with personality disorder and that central and/or peripheral NE may play a role in modulating aggressive behavior in these subjects.

Aggression: the testosterone-serotonin link

The relevance of central neurotransmission to aggressive and impulsive behavior has become more evident due to extensive research in humans and animals. Among other findings, there are abundant data relating low serotonergic activity--as measured by low cerebrospinal fluid 5-hydroxyindolacetic acid, and a blunted response of prolactin to fenfluramine--to impulsive behavior. Many studies on testosterone activity show a relation between high plasma levels and a tendency towards aggression. It is hypothesized that the interaction between low serotonin and high testosterone levels in the central nervous system has a significant effect on the neural mechanisms involved in the expression of aggressive behavior. It seems that testosterone modulates serotonergic receptor activity in a way that directly affects aggression, fear and anxiety. Our survey reviews the main findings on serotonin, testosterone and the possible interaction between them with regard to these behavioral phenomena.

Impulsivity and prefrontal hypometabolism in borderline personality disorder

Prefrontal hypoperfusion and decreased glucose uptake in the prefrontal cortex (PFC) are found in violent criminal offenders, murderers and aggressive psychiatric patients. These abnormalities may be independent of diagnosis and associated with impulsive-aggression as a personality trait. Impulsive-aggression is a clinical characteristic of borderline personality disorder (BPD) where it is associated with assaultive and suicidal behaviors. We conducted FDG-PET studies in 13 non-depressed, impulsive female subjects with BPD and 9 healthy controls to look for abnormalities in glucose metabolism in areas of the PFC associated with regulation of impulsive behavior. Statistical Parametric Mapping-99 (SPM99) was used to analyze the PET data with Hamilton depression scores as covariate. Significant reductions in FDG uptake in BPD subjects relative to healthy controls were found bilaterally in medial orbital frontal cortex, including Brodmann's areas 9, 10 and 11. There were no significant areas of increased uptake in BPD subjects compared to control subjects. Covarying for measures of impulsivity or impulsive-aggression rendered insignificant the differences between groups. Decreased glucose uptake in medial orbital frontal cortex may be associated with diminished regulation of impulsive behavior in BPD.

Prefrontal 5-HT2a receptor binding index, hopelessness and personality characteristics in attempted suicide

BACKGROUND

Depression, hopelessness, impaired problem solving capacities and deficient serotonergic functions have been identified as major causes of suicidal behaviour. In general, the relation between biological markers of attempted suicide and psychological functions has been investigated using indirect peripheral markers of, e.g. the serotonergic system. Recently, functional neuroimaging techniques with radioligands allow direct in vivo assessment of the neurobiological status of the central nervous system.

METHODS

We studied the binding index of serotonin-(2a) (5-HT(2a)) receptors in the frontal cortex of attempted suicide patients (n=9) and normal controls (n=13) using [123I]5-I-R91150, a highly selective 5-HT(2a) receptor ligand. Moreover, we measured personality characteristics (using Cloninger's Temperament and Character Inventory) and levels of hopelessness (using Beck's Hopelessness Scale), and studied the association between 5-HT(2a) receptor binding index, hopelessness and these personality dimensions.

RESULTS

When compared to normal controls, attempted suicide patients had a significantly lower binding potential of frontal 5-HT(2a) receptors, a higher level of hopelessness, a higher score on the temperament dimension harm avoidance and lower scores on the character dimensions self-directedness and cooperativeness. A significant correlation was found between harm avoidance, hopelessness and binding index in the population of patients that attempted suicide.

LIMITATIONS

The limited number of patients and potential ingestion of psychotropic drugs may influence the results of the study.

CONCLUSIONS

Lower central serotonergic function, hopelessness and harm avoidance are interrelated phenomena, which may increase the probability of the occurrence of attempted suicide.

Pathological gambling. A comprehensive review

Due to recent changes of gambling laws, accessibility to gambling has become more widespread and thus, there has also been an increase in the prevalence of pathological gambling (PG). The wide range of social, economic, and psychological problems associated with PG are well known. There is a need for better understanding of PG and this review attempts to do so. Literature searches using the Medline and PsycINFO databases were used. Critical examining of the literature showed that familial/genetic, sociological, and individual factors (e.g., an individual's personality, biochemistry, psychological states, and cognitions) are implicated in the development and maintenance of PG, yet at present, the evidences are not solid. Similarly, there have been a lot of theories for PG but again, none of them are solid enough to provide a clear understanding of PG. Recent psychological-based theories seem to provide some solid ground for further research. We highlight four areas for future consideration for research. (1) Most studies have generalized findings from one form of gambling to another. It is suggested that it is now not tenable to consider gambling as a single phenomenon that can explain all forms of gambling. (2) Almost all of the studies in the gambling literature are Western-based and the results are often generalized to other ethnic and cultural groups. There is now an urgent need to close this gap. (3) Future studies need to address methodological problems in the current gambling/PG literature. (4) Almost all of the gambling literature has focused on the issue of why people start gambling. It is suggested that looking at variables as to why people stop gambling in a single episode may be a more fruitful area of research then why people start gambling. This is because what motivates one to continue gambling, despite losses in a session and across sessions, is a characteristic that distinguishes nonproblem gamblers from problem gamblers and pathological gamblers (PGs).

The search for determinants of chronic depression: a review of six factors

While strides have been made in the classification, assessment and identification of chronic depression, there remains a limited understanding of the factors underlying chronicity. This review focuses on six putative determinants of chronic depression: developmental factors, personality and personality disorders, psychosocial stressors, comorbid disorders, biological factors and cognitive factors. The strongest support was found for the role of developmental factors in the chronicity of depression. Some support was found for the role of chronic stressors and certain personality features such as stress reactivity. Few other factors found support. The determinants of chronic depression do not differ qualitatively from acute depression. Rather, the development of chronic depression may involve increased levels of childhood adversity, protracted environmental stress and heightened stress reactivity. However, it is difficult to determine to what extent these putative determinants might reflect retrospective bias in data collection, or even parental reaction to children with subthreshold depressive traits. Detailed etiological models await further research attention to understudied areas and improved research designs. Suggestions for future research include greater specification of criteria for chronicity, use of more appropriate comparison groups and longer term prospective follow-up studies.

[Dopamine receptor gene (DRD2) polymorphism in patients with endogenous psychoses with regard to their clinical heterogeneity]

Recently an association between genetic dopamine receptor gene (DRD2) polymorphism and schizophrenia was observed in several studies. In the current investigation we attempted to undertake further study of such association using an extended sample which comprised patients with schizophrenia (n = 184), schizoaffective psychosis (n = 63), affective disorders (n = 121)); healthy control subjects (n = 117) and first-degree relatives of the patients with psychoses who show no signs of mental diseases (n = 111). The genotypes A1A1, A1A2 and A2A2 and the relationship between Taq1DRD2 variants and some clinical symptoms and pathogenetic features of the patients with schizophrenia were studied. The results did not confirm the association between DRD2 genotype and any of disorders studied. But the A2A2 genotype frequency in the schizophrenic patient's group, with illness duration above 20 years and highly expressed positive, negative and psychopathological symptoms, increased significantly as compared to control group (73.7% vs 52.9%) and patients with less illness duration (73.7% vs 42.5%). In the latter case odds ratio was calculated as 4.12. In the light of this finding, A2A2 DRD2 genotype appears to be related to chronicity of schizophrenia.

Developmental changes in cortisol secretion in normal and at-risk youth

Adolescence is associated with an increase in the rate of certain psychiatric symptoms, and it is typically the developmental period when prodromal features of the major psychiatric disorders emerge. This is especially true of schizophrenia, with the majority of patients showing a marked postpubertal rise in schizotypal signs that predates the onset of clinical symptoms in early adulthood. Cross-sectional studies of youth have revealed a positive correlation between age and saliva cortisol level, suggesting a normative maturational increase in activity of the hypothalamic-pituitary-adrenal (HPA) axis. It has been hypothesized that this increase may trigger the expression of symptoms in vulnerable individuals. The present longitudinal study measured cortisol secretion and its relation with symptom development in samples of youth with schizotypal personality disorder (SPD), other personality disorders, or no Axis II disorder. The findings indicate moderate stability in cortisol levels across a 2-year period, with a longitudinal increase in cortisol levels over time. Cortisol levels at the first and second assessments were correlated with the severity of SPD symptoms at follow-up. The results are consistent with the notion that the HPA axis undergoes a postpubertal maturational process that moderates the expression of psychiatric symptoms.

Selected biochemical parameters of blood serum in soldiers committing self-mutilation

OBJECTIVE

This project attempts to establish a possible link between selected biochemical parameters (cholesterol and triglyceride concentrations and levels of malonyl dialdehyde and superoxide dismutase) in soldiers with autoaggressive behaviors.

MATERIALS AND METHODS

The study involved 33 soldiers treated for self-aggressive behavior from July 1, 1998, to June 30, 1999. Average patient age was 20.7 years. The control group consisted of 21 soldiers hospitalized for mental disturbances but not showing autoaggressive tendencies. Total cholesterol and activity of platelets, considering the generation of free radicals and triglyceride concentration levels, were determined in the blood serum of members of both groups.

RESULTS

The results indicate significantly lower concentrations of total cholesterol in the serum of soldiers showing self-aggressive behaviors. Also, increased concentrations of malonyl dialdehyde in blood platelets and decreased superoxide dismutase activity were found in individuals prone to autoaggression.

CONCLUSION

The results suggest that the dysfunction of oxidation-reduction processes in brain tissue leads to excessive generation of free radicals, which can cause brain cell damage and disturb metabolic processes, resulting in mental disturbances that may constitute a background for self-aggressive behavior. The decreased activity of superoxide dismutase is a major factor in the observed oxidation-reduction disturbances.

Relationships between personality disorders and anthropometry, hormones and metabolism in women

This study sought to examine the potential influence of personality disorders (PD) on anthropometry, hormones and metabolism in women. In a population sample of women born in 1956 (no.=270), estimates of PD:s by Structured Clinical Interview for DSM-III-R, Axis II, were correlated with anthropometric, endocrine, and metabolic factors. The PD:s were grouped into three thematic clusters: cluster A (characterized by oddness or eccentricity), cluster B (characterized by self-centeredness, emotionality, and erratic behavior) and cluster C (characterized by anxiety and fear). Subjects with cluster A PD:s had significantly increased body mass index (BMI, kg/m2) and abdominal sagittal diameter (cm) as well as lower salivary cortisol after dexamethasone (DEX) compared to controls. Subjects with cluster B also had a significantly higher abdominal sagittal diameter and significantly lower salivary cortisol levels after DEX than controls. In addition, subjects with cluster B PD:s had decreased levels of ACTH, and significantly higher concentrations of lactate and triglycerides, while high-density lipoprotein (HDL) cholesterol was significantly lower compared to controls. A significantly higher waist/hip ratio was seen among subjects with cluster C PD:s. In addition, these subjects had higher levels of insulin, glucose, lactate, triglycerides, total cholesterol and low-density lipoprotein (LDL) cholesterol than controls. Moreover, IGF-I and HDL cholesterol were significantly decreased in the former group. These results suggest that PD:s are involved in the development of obesity and abdominal fat accumulation in women, with different endocrine and metabolic profiles depending on the type of PD.

Pet studies of serotonin synthesis in the human brain

The method for measuring serotonin synthesis in human brain uses [11C]alpha-methyl-L-tryptophan as a tracer and positron emission tomography. The alpha-methyl-L-tryptophan is converted to alpha-methylserotonin, which is not a substrate for monoamine oxidase and therefore accumulates in the brain. In a pilot study published recently, rates of serotonin synthesis were found to be higher in men than in women. This was due to the lower plasma free tryptophan in the women under the experimental conditions used, and does not necessarily reflect the situation in all circumstances. Acute tryptophan depletion lowered brain serotonin synthesis by 90% or more. Patients with borderline personality disorder, who exhibit emotional lability and impulsivity, may have lower brain serotonin synthesis rates than healthy controls.

Low HDL cholesterol, aggression and altered central serotonergic activity

Many studies support a significant relation between low cholesterol levels and poor impulse, aggression and mood control. Evidence exists also for a causal link between low brain serotonin (5-HT) activity and these behaviors. Mechanisms linking cholesterol and hostile or self-destructive behavior are unknown, but it has been suggested that low cholesterol influences 5-HT function. This study was designed to explore the relationship between plasma cholesterol, measures of impulsivity and aggression, and indices of 5-HT function in personality disordered cocaine addicts. Thirty-eight hospitalized male patients (age 36.8+/-7.1) were assessed with the DSM-III-R, the Buss-Durkee Hostility Inventory (BDHI), the Barratt Impulsiveness Scale (BIS) and the Brown-Goodwin Assessment for Life History of Aggression. Fasting basal cholesterol (total, LDL and HDL) was determined 2 weeks after cocaine discontinuation. On the same day 5-HT function was assessed by neuroendocrine (cortisol and prolactin) and psychological (NIMH and 'high' self-rating scales) responses following meta-chlorophenylpiperazine (m-CPP) challenges. Reduced neuroendocrine responses, 'high' feelings and increased 'activation-euphoria' following m-CPP have been interpreted as indicating 5-HT alterations in a variety of psychiatric conditions. Significantly lower levels of HDL cholesterol were found in patients who had a history of aggression (P=0.005). Lower levels of HDL cholesterol were also found to be significantly associated with more intense 'high' and 'activation-euphoria' responses as well as with blunted cortisol responses to m-CPP (P=0.033, P=0.025 and P=0.018, respectively). This study gives further support to existing evidence indicating that in some individuals, the probability of exhibiting impulsive and violent behaviors may be increased when cholesterol is low. It also suggests that low cholesterol and alterations in 5-HT activity may be causally related.

Borderline personality disorder. Overview of biologic factors

Exploring the biology of neurotransmitters and polymorphic genes that influence behavior most certainly will increase understanding of the complexity of personality disorders and the people who suffer with them. Continuing biologic exploration of the personality disorders will also provide new and valuable information that will inform and direct ever more sophisticated and specific psychiatric treatments. Further, it will supply knowledge that might begin to erode the strong biases and negative labels that have for too long been applied to these patients. These labels may have been applied not because these patients are bad people, but because of ignorance in understanding their complexity and limited ability to improve their condition. Nonetheless, clinicians must refrain from concluding that the answers to all problems in psychiatric treatment can be answered by the molecular geneticist or biologic researcher. As Reiss et al have written when speaking about nonshared environmental effects and its role in the development of psychopathology: "Psychiatry has been forced into the chronically uncomfortable position of straddling biomedicine and the social sciences and seems always to hunger for relief.... [Yet] the data simply do not permit a conception of the future centered on a straightforward biomedical answer to the fundamental question of the pathogenesis of major disorders. Indeed, a balanced image of the future contains a growing and equal partnership of the social sciences and molecular biology."

Harm avoidance and serotonin

The relationships between the Tridimensional Personality Questionnaire (TPQ) and serotonergic activity has been described in some studies with controversial results. These studies have focused on specific patient populations rather than normal controls. Therefore, the aim of the present study is to examine the relationships between the TPQ and serotonergic activity in a group of non-patient subjects. Twenty-three normal subjects answered the TPQ, and the serotonergic activity was assessed by the prolactin response to a highly potent and selective 5-HT1a agonist (flesinoxan). A positive relationship between harm avoidance and PRL response to flesinoxan was found. This study is consistent with the hypothesized link between serotonergic activity and the harm avoidance dimension of the biosocial model of Cloninger.

Personality disorders in relation to anthropometric, endocrine and metabolic factors

Subjects with abdominal obesity show several signs of a perturbed regulation of the hypothalamic-pituitary-adrenal (HPA) axis. This is known to occur after chronic, submissive stress. Perceived environmental stress is depending on personality characteristics. Therefore, personality disorders (PD:s) were examined in relation to HPA axis status, other endocrine and metabolic variables as well as anthropometry. Men (no.=284) aged 51 years, recruited in similar subgroups of low, median and high waist/hip circumference ratio (WHR) from a sample of 1302 men. Measurements of personality disorders by Structured Clinical Interview for DSM-III-R, Axis II (SCID II), body mass index (BMI, weight, kg/height2, m2), WHR and abdominal sagittal diameter (D), dexamethasone suppression test (0.5 mg, salivary measurements of cortisol), insulin-like growth factor I (IGF-I), testosterone and metabolic variables. Men with cluster A (paranoid, schizotypal, schizoid) PD showed an increased BMI, WHR and D, independent of dexamethasone suppression. Testosterone was decreased in these men in relation to a blunted dexamethasone suppression. BMI, WHR and D were increased in men with cluster B (borderline, histrionic, narcissistic) and cluster C (avoidant, dependent, obsessive compulsive, passive aggressive) PD, only in relation to a blunted dexamethasone suppression. Furthermore, IGF-I was low in cluster B. Metabolic variables were differently associated to clusters of PD but generally followed obesity. Path-analytic models suggested that cluster B and C PD were followed by blunted dexamethasone suppression and obesity. Men with cluster A PD showed centralized body fat distribution, independently of dexamethasone suppression. In contrast, men with impulsive (cluster B) and anxious (cluster C) personality disorders seem often to have abdominal obesity only in combination with a blunted dexamethasone suppression test, suggesting a HPA axis disturbance. These results suggest that PD:s are involved in the development of abdominal obesity in men, with different endocrine and metabolic profiles depending on the type of PD. This might hypothetically be due to frequent exposure and/or an increased sensitivity to environmental stress factors, caused by aberrant personalities.

Impulsive aggression in personality disorder correlates with platelet 5-HT2A receptor binding

The purpose of this study was to examine the relationship between platelet 5-HT2A receptor binding and aggressive behavior. 125I-LSD Bmax and Kd values were measured for 22 subjects meeting DMS-III-R criteria for one or more personality disorders and 12 healthy volunteer subjects. Aggression and impulsivity were assessed using the Buss-Durkee Hostility Inventory (BDHI) Assault scale, Life History of Aggression (LHA) scale, and the Barratt-11 Impulsiveness scale (BIS-11). Bmax and Kd values did not differ between personality disordered subjects and healthy volunteers. However, both Bmax and Kd values correlated positively with BDHI Assault scores in personality-disordered subjects but not in healthy volunteer subjects. These results suggest that assaultiveness in personality-disordered subjects may covary with increasing numbers, but decreasing affinity, of platelet 5-HT2A receptor sites labeled by 125I-LSD.

Physiological responses to d-fenfluramine and ipsapirone challenge correlate with indices of aggression in males with personality disorder

Hormonal responses to challenge with the 5-HT2A/2C probe d-fenfluramine and hormonal and thermal responses to challenge with the 5-HT1A probe ipsapirone were correlated with self-report and historical assessments of aggression in a pilot sample of eight male personality-disordered individuals. Prolactin responses to d-fenfluramine and cortisol responses to ipsapirone challenge were inversely correlated with self-reported assaultiveness. Thermal responses to ipsapirone were inversely correlated with a historical assessment of aggression. Since none of these physiological indices of 5-HT system function were intercorrelated, it is possible that simultaneous assessment of these 5-HT indices may yield a more comprehensive assessment of the relationship between central 5-HT system function and aggressive behavior in humans.

[The violent patient]

The article examines the violence which falls within the domain of the physician. It describes the different patterns of aggressive behavior, the frequency of crimes among psychiatric patients, the violence-related diseases, the main risk-factors. Guidelines are suggested for the examination (interview technique, content of the evaluation, assessment of the danger of violence) and the treatment in the acute and long-term management of violent patients with a particular emphasis on pharmacologic therapy. The neurophysiological, pathological and neurochemical bases of aggression, inhibition and episodic dyscontrol are discussed as well as the most relevant socio-cultural factors.

The TRH-stimulation test in DSM-III personality disorder

The authors examined thyrotropin-releasing hormone (TRH) stimulation testing in the neuroendocrine evaluation of DSM-III major depressive disorder in 26 consecutive medication-free, medically healthy patients meeting a primary DSM-III diagnosis of axis II personality disorder. Thyroid-stimulating hormone (TSH) responses to TRH challenge were not significantly different between patients with or without major depression at time of study, or between patients with or without a life history of major affective disorder. Further, TSH responses to TRH among 11 healthy male nonpsychiatric controls were not significantly different from those in patients with personality disorders. Comparison of those patients with blunted TSH responses (< 7.0 microU/ml) versus those without blunted response (< or = 7.0 microU/ml) also did not reveal a significant difference. In addition, the TSH response to TRH did not correlate with dimensional assessments of state or trait depression, anxiety, or with past history of suicide attempt or alcohol abuse. These data suggest that TRH stimulation testing has limited utility in the evaluation of major depression or other relevant affective states/traits in personality-disordered patients. Affective symptoms in personality-disordered patients do not seem to be associated with dysregulation of the hypothalamic-pituitary-thyroid axis.