Endophenotypes in the personality disorders

Reliability and factorial validity of long and brief versions of the inventory of personality organization in a Latvian sample

The aim of this study was to examine the construct validity and reliability of long and brief versions (57 and 16 items) of the Inventory of Personality Organization (IPO) in a Latvian non-clinical sample. The actuality of this study is dictated by the number of persons suffering from personality disorders, and the excessive need for reliable constructs for the assessment of personality in the normality-abnormality range. The total number of participants of the study was 1118, recruited in several subsamples, which were employed for the investigation of the factor structure, psychometric properties, test-retest, and convergent validity of the IPO-57 and IPO-16 scales. The 3-factor structure, obtained by confirmatory factor analysis, was replicated in the Latvian-speaking sample for long and brief IPO versions. Both constructs achieved adequate model fit psychometric indices and sufficient internal consistency, and the test-retest reliability was also approved. The convergent validity of IPO with aggressivity, negative affectivity, and non-adaptive personality measures was established. In the current study, we adapted a very fundamental psychodynamic/psychoanalytic construct in the Latvian language and replicated the previously empirically established IPO three-dimensional model, whereas the novelty in IPO construct convergent validity research was the establishment of convergent validity with non-adaptive personality traits measured by the Personality Inventory for DSM-5 Brief Form (PID-5-BF). Both versions of IPO are recommended for further use in the research in Latvian language samples, for clinical purposes to assess the level of psychic functioning, and for treatment planning and evaluation purposes.

Heschl's gyrus duplication pattern and clinical characteristics in borderline personality disorder: A preliminary study

Inter-individual variations in the sulco-gyral pattern of Heschl's gyrus (HG) might contribute to emotional processing. However, it remains largely unknown whether borderline personality disorder (BPD) patients exhibit an altered HG gyrification pattern, compared with healthy individuals, and whether such a brain morphological feature, if present, might contribute to their clinical characteristics. The present study used magnetic resonance imaging to investigate the distribution of HG gyrification patterns (single or duplicated) and their relationship to clinical characteristics in teenage BPD patients with minimal treatment exposure. No significant difference was noted for the prevalence of HG patterns between 20 BPD and 20 healthy participants. However, the BPD participants with left duplicated HG were characterized by higher prevalence of comorbid disruptive behavior disorders, with higher externalizing score compared with those with left single HG. Our preliminary results suggest that neurodevelopmental pathology associated with gyral formation might be implicated in the neurobiology of early BPD, especially for emotional and behavioral control.

Borderline Personality Disorder in Patients With Medical Illness: A Review of Assessment, Prevalence, and Treatment Options

OBJECTIVE

Borderline personality disorder (BPD) occurs in 0.7% to 3.5% of the general population. Patients with BPD experience excessive comorbidity of psychiatric and somatic diseases and are known to be high users of health care services. Because of a range of challenges related to adverse health behaviors and their interpersonal style, patients with BPD are often regarded as "difficult" to interact with and treat optimally.

METHODS

This narrative review focuses on epidemiological studies on BPD and its comorbidity with a specific focus on somatic illness. Empirically validated treatments are summarized, and implementation of specific treatment models is discussed.

RESULTS

The prevalence of BPD among psychiatric inpatients (9%-14%) and outpatients (12%-18%) is high; medical service use is very frequent, annual societal costs vary between &OV0556;11,000 and &OV0556;28,000. BPD is associated with cardiovascular diseases and stroke, metabolic disease including diabetes and obesity, gastrointestinal disease, arthritis and chronic pain, venereal diseases, and HIV infection as well as sleep disorders. Psychotherapy is the treatment of choice for BPD. Several manualized treatments for BPD have been empirically validated, including dialectical behavior therapy, transference-focused psychotherapy, mentalization-based therapy, and schema-focused therapy.

CONCLUSIONS

Health care could be substantially improved if all medical specialties would be familiar with BPD, its pathology, medical and psychiatric comorbidities, complications, and treatment. In mental health care, several empirically validated treatments that are applicable in a wide range of clinical settings are available.

Schizotypal personality disorder

Early phenomenological descriptions of schizophrenia have acknowledged the existence of milder schizophrenia spectrum disorders characterized by the presence of attenuated symptoms typically present in chronic schizophrenia. The investigation of the schizophrenia spectrum disorders offers an opportunity to elucidate the pathophysiological mechanisms giving rise to schizophrenia. Differences and similarities between subjects with schizotypal personality disorder (SPD), the prototypical schizophrenia personality disorder, and chronic schizophrenia have been investigated with genetic, neurochemical, imaging, and pharmacological techniques. Patients with SPD and the more severely ill patients with chronic schizophrenia share cognitive, social, and attentional deficits hypothesized to result from common neurodevelopmentally based cortical temporal and prefrontal pathology. However, these deficits are milder in SPD patients due to their capacity to recruit other related brain regions to compensate for dysfunctional areas. Individuals with SPD are also less vulnerable to psychosis due to the presence of protective factors mitigating subcortical DA hyperactivity. Given the documented close relationship to other schizophrenic disorders, SPD will be included in the psychosis section of DSM-5 as a schizophrenia spectrum disorder as well as in the personality disorder section.

Toward a definition of affective instability

Affective instability is a psychophysiological symptom observed in some psychopathologies. It is a complex construct that encompasses (1) primary emotions, or affects, and secondary emotions, with each category having its own characteristics, amplitude, and duration, (2) rapid shifting from neutral or valenced affect to intense affect, and (3) dysfunctional modulation of emotions. Affective instability is often confused with mood lability, as in bipolar disorders, as well as with other terms. To clarify the concept, we searched databases for the term affective instability and read related articles on the topic. In this article we situate the term within the current affective nomenclature and human emotional experience, explore its psychophysiological features, and place it within the context of psychopathology. We explain why the term can potentially be confused with mood pathology and then define affective instability as an inherited temperamental trait modulated by developmental experience.

The neuroscience of suicidal behaviors: what can we expect from endophenotype strategies?

Vulnerability to suicidal behavior (SB) is likely mediated by an underlying genetic predisposition interacting with environmental and probable epigenetic factors throughout the lifespan to modify the function of neuronal circuits, thus rendering an individual more likely to engage in a suicidal act. Improving our understanding of the neuroscience underlying SBs, both attempts and completions, at all developmental stages is crucial for more effective preventive treatments and for better identification of vulnerable individuals. Recent studies have characterized SB using an endophenotype strategy, which aims to identify quantitative measures that reflect genetically influenced stable changes in brain function. In addition to aiding in the functional characterization of susceptibility genes, endophenotypic research strategies may have a wider impact in determining vulnerability to SB, as well as the translation of human findings to animal models, and vice versa. Endophenotypes associated with vulnerability to SB include impulsive/aggressive personality traits and disadvantageous decision making. Deficits in realistic risk evaluation represent key processes in vulnerability to SB. Serotonin dysfunction, indicated by neuroendocrine responses and neuroimaging, is also strongly implicated as a potential endophenotype and is linked with impulsive aggression and disadvantageous decision making. Specific endophenotypes may represent heritable markers for the identification of vulnerable patients and may be relevant targets for successful suicide prevention and treatments.

Borderline personality disorder traits and their relationship with dimensions of normative personality: a web-based cohort and twin study

OBJECTIVE

To describe the structure of genetic and environmental risk factors for four dimensions of borderline personality disorder (BPD) and to understand the source of resemblance of these dimensions and normal personality.

METHOD

A web-based sample (n = 44,112 including 542 twin pairs) completed items from 4 scales of the Dimensional Assessment of Personality Pathology Basic Questionnaire and the Big Five Inventory.

RESULTS

A one-factor common pathway model best fits the 4 BPD scales producing a highly heritable latent liability (heritability = 60%) and strong loadings on all 4 dimensions. Affective instability had the lowest trait-specific genetic loading, suggesting that it was a core feature of BPD. A complex pattern of genetic and environmental associations was found between the big five personality traits and BPD dimensions. The strongest genetic correlations with the BPD traits were generally seen for neuroticism (positive), followed by conscientiousness and agreeableness, both negative.

CONCLUSION

In the general population, these four BPD dimensions reflect one underlying highly heritable factor. The association between normative personality and dimensions of BPD is complex with high degrees of genetic correlation.

Superior temporal gyrus volume in teenagers with first-presentation borderline personality disorder

This magnetic resonance imaging study investigated the superior temporal gyrus (STG) subregion volumes in 20 teenagers with first-presentation borderline personality disorder (BPD) and 20 healthy controls. While the STG volume early in the course of BPD did not differ from that of healthy controls, the BPD participants with violent episodes had a smaller left caudal STG volume compared with those without such episodes during the previous 6 months. Our preliminary findings might reflect the neurobiological heterogeneity of the disorder.

The genetic epidemiology of personality disorders

Genetic epidemiologic studies indicate that all ten personality disorders (PDs) classified on the DSM-IV axis II are modestly to moderately heritable. Shared environmental and nonadditive genetic factors are of minor or no importance. No sex differences have been identified. Multivariate studies suggest that the extensive comorbidity between the PDs can be explained by three common genetic and environmental risk factors. The genetic factors do not reflect the DSM-IV cluster structure, but rather: i) broad vulnerability to PD pathology or negative emotionality; ii) high impulsivity/low agreeableness; and iii) introversion. Common genetic and environmental liability factors contribute to comorbidity between pairs or clusters of axis I and axis II disorders. Molecular genetic studies of PDs, mostly candidate gene association studies, indicate that genes linked to neurotransmitter pathways, especially in the serotonergic and dopaminergic systems, are involved. Future studies, using newer methods like genome-wide association, might take advantage of the use of endophenotypes.

Insular cortex volume and impulsivity in teenagers with first-presentation borderline personality disorder

Fronto-limbic neural dysfunction has been implicated in the emotional dysregulation and impulsivity seen in borderline personality disorder (BPD). However, it remains unclear whether affected individuals exhibit morphologic changes of the insular cortex, a fronto-limbic integration cortex engaged in emotional regulation and impulse control. This magnetic resonance imaging study examined the insular cortex volume and its relationship to clinical characteristics in a first-presentation teenage BPD sample. No significant difference was found in the insular volume between 20 BPD participants (5 males) and 20 healthy control participants (5 males). There was no association between the insular volume and parasuicidal episodes, trauma exposure, or comorbid Axis I disorders, but the BPD participants with violent episodes during the previous 6 months had a smaller insular volume bilaterally compared with those without such episodes. Furthermore, right anterior insular volume in the BPD participants was negatively correlated with impulsivity score. These preliminary findings suggest that insular cortex volume does not significantly differ in early BPD, but that there might be a relationship with violent and impulsive behavior that is often seen in the disorder. Further studies are needed to clarify whether the potential relationship between the insular cortex volume and impulsivity is specific to BPD.

Genetics of personality disorders

This review of the literature on genetic contributions to the etiology of personality disorders broadly follows the DSM classification, and begins by evaluating the current evidence for genetic influences on the DSM axis II disorders. One of the most exciting directions in psychiatric genetics is the rapidly developing field of molecular genetic studies aiming to identify specific genes correlated with psychiatric phenotypes. Personality disorders, like most other psychiatric diagnostic categories, are etiologically complex, which implies that they are influenced by several genes and several environmental factors. The interplay between genes and the environment is a field that is receiving increasing attention and is addressed both in relation to quantitative and molecular methods.

Recent advances in the biological study of personality disorders

While it is premature to provide a simple model for the vulnerability to the development of either borderline (BPD) or schizotypal (SPD) personality disorder, it is clear that these heritable disorders lend themselves to fruitful neurobiological exploration. The most promising findings in BPD suggest that a diminished top-down control of affective responses, which is likely to relate to deceased responsiveness of specific midline regions of prefrontal cortex, may underlie the affective hyperresponsiveness in this disorder. In addition, genetic and neuroendocrine and molecular neuroimaging findings point to a role for serotonin in this affective disinhibition. Clearly SPD falls within the schizophrenia spectrum, but precisely the nature of what predicts full-blown schizophrenia as opposed to the milder symptoms of SPD is not yet clear.

Emotional processing in male adolescents with childhood-onset conduct disorder

BACKGROUND

Boys with early onset of conduct disorder (CD), most of whom also meet diagnostic criteria of a comorbid attention deficit hyperactivity disorder (ADHD), tend to exhibit high levels of aggression throughout development. While a number of functional neuroimaging studies on emotional processing have been performed in antisocial adults, little is known about how CD children process emotional information.

METHOD

Functional magnetic resonance imaging data were analyzed in 22 male adolescents aged 12 to 17 years with childhood-onset CD (16 of them with comorbid ADHD) compared to 22 age-matched male healthy controls. In order to consider the likely confounding of results through ADHD comorbidity, we performed a supplementary study including 13 adolescent subjects with pure ADHD who were compared with healthy controls. To challenge emotional processing of stimuli, a passive viewing task was applied, presenting pictures of negative, positive or neutral valence.

RESULTS

When comparing CD/combined disorder patients with healthy controls, we found enhanced left-sided amygdala activation in response to negative pictures as compared to neutral pictures in the patient group. In addition, these boys exhibited no reduced activation in the orbitofrontal, anterior cingulate and insular cortices. By contrast, children with pure ADHD did not show any abnormalities in amygdala activation but showed decreased neural activity in the insula only in response to negative pictures.

CONCLUSIONS

Increased rather than reduced amygdala activation found in our study may indicate an enhanced response to environmental cues in adolescents with early-onset CD (most of whom also met the condition of ADHD), and is not consistent with the assumption of a reduced capacity to take note of affective information in the social environment. Further studies with an emphasis on developmental aspects of affect regulation are needed to clarify the relationship between CD and adult personality pathology associated with different modes of persistent antisocial behavior.

Sex, aggression and impulse control: an integrative account

There is evidence that the male sex and a personality style characterized by low self-control/high impulsivity and a propensity for negative emotionality increase the risk for impulsive aggressive, antisocial and criminal behavior. This article aims at identifying neurobiological factors underlying this association. It is concluded that the neurobiological correlates of impulsive aggression act through their effects on the ability to modulate impulsive expression more generally, and that sex-related differences in the neurobiological correlates of impulse control and emotion regulation mediate sex differences in direct aggression. A model is proposed that relates impulse control and its neurobiological correlates to sex differences in direct aggression.

Psychiatric endophenotypes and the development of valid animal models

Endophenotypes are quantifiable components in the genes-to-behaviors pathways, distinct from psychiatric symptoms, which make genetic and biological studies of etiologies for disease categories more manageable. The endophenotype concept has emerged as a strategic tool in neuropsychiatric research. This emergence is due to many factors, including the modest reproducibility of results from studies directed toward etiologies and appreciation for the complex relationships between genes and behavior. Disease heterogeneity is often guaranteed, rather than simplified, through the current diagnostic system; inherent benefits of endophenotypes include more specific disease concepts and process definitions. Endophenotypes can be neurophysiological, biochemical, endocrine, neuroanatomical, cognitive or neuropsychological. Heritability and stability (state independence) represent key components of any useful endophenotype. Importantly, they characterize an approach that reduces the complexity of symptoms and multifaceted behaviors, resulting in units of analysis that are more amenable to being modeled in animals. We discuss the benefits of more direct interpretation of clinical endophenotypes by basic behavioral scientists. With the advent of important findings regarding the genes that predispose to psychiatric illness, we are at an important crossroads where, without anthropomorphizing, animal models may provide homologous components of psychiatric illness, rather than simply equating to similar (loosely analogized) behaviors, validators of the efficacy of current medications or models of symptoms. We conclude that there exists a need for increased collaboration between clinicians and basic scientists, the result of which should be to improve diagnosis, classification and treatment on one end and to increase the construct relevance of model organisms on the other.