The genetics of personality disorder

The Endurance of Uncertainty: Antisociality and Ontological Anarchy in British Psychiatry, 1950–2010

Research into the biological markers of pathology has long been a feature of British psychiatry. Such somatic indicators and associated features of mental disorder often intertwine with discourse on psychological and behavioral correlates and causes of mental ill-health. Disorders of sociality – particularly psychopathy and antisocial personality disorder – are important instances where the search for markers of pathology has a long history; research in this area has played an important role in shaping how mental health professionals understand the conditions. Here, I characterize the multiplicity of psychiatric praxis that has sought to define the mark of antisociality as a form of “ontological anarchy.” I regard this as an essential feature of the search for biological and other markers of an unstable referent, positing that uncertainties endure – in part – precisely because of attempts to build consensus regarding the ontology of antisociality through biomedical means. Such an account is suggestive of the co-production of biomarkers, mental disorder, and psychiatric institutions.

The neuropsychology of prefrontal function in antisocial personality disordered offenders with varying degrees of psychopathy

BACKGROUND

Despite methodological differences between studies, it has been suggested that psychopathy may be associated with a ventromedial prefrontal cortex (VMPFC) deficit and antisocial personality disorder (ASPD), as classified in the DSM-IV, with a broader range of deficits in dorsolateral prefrontal cortex (DLPFC) and VMPFC function.

METHOD

Ninety-six male offenders with ASPD who were assessed using the psychopathy checklist: screening version (PCL:SV) and 49 male right-handed healthy controls (HCs), matched for age and IQ, completed a neuropsychological test battery.

RESULTS

Offenders with ASPD displayed subtle impairments on executive function tasks of planning ability and set shifting and behavioural inhibition compared to HCs. However, among the offenders with ASPD there was no significant association between executive function impairment and scores on the measure of psychopathy.

CONCLUSIONS

Psychopathic traits in offenders with ASPD are not associated with greater executive function impairment.

Childhood antecedents of personality disorder: an alternative perspective

One of the fundamental limitations of the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, Text Revision (DSM-IV-TR) categorical model of personality disorder classification has been the lack of a strong scientific foundation, including an understanding of childhood antecedents. The DSM-IV-TR personality disorders, however, do appear to be well understood as maladaptive variants of the domains and facets of the general personality structure as conceptualized within the five-factor model (FFM). Integrating the classification of personality disorder with the FFM brings to an understanding of the personality disorders a considerable body of scientific research on childhood antecedents. The temperaments and traits of childhood do appear to be antecedent to the FFM of adult personality structure, and these temperament and traits of childhood and adolescence are the likely antecedents for adult personality disorder, providing further support for the conceptualization of the adult personality disorders as maladaptive variants of the domains and facets of the FFM. Conceptualizing personality disorders in terms of the FFM thereby provides a basis for integrating the classification of abnormal and normal personality functioning across the life span.

Personality disorder and drug use: a review

The concept of personality disorder (PD) is more relevant in the clinical management of drug users than other approaches to personality assessment. A problem in diagnosis is separating behaviours inherent in the activity of drug misuse from true evidence of PD, especially the anti-social type (ASPD), and rating instruments vary in their ability to do this. Nevertheless, the available evidence suggests that approximately two-thirds of drug users in treatment have PD, with ASPD the most common. Studies have mainly been in opiate users, while the prevalence of PD may be lower across the range of drugs, and in non-treatment settings. PD has been found to be associated with a range of complications and adverse outcomes in drug use, including psychiatric problems, poor social functioning, dropout from treatment, and increased HIV risk behaviours and infection rates. Outcomes for ASPD individuals in methadone maintenance treatment appear reasonable, however, and it may be that early recourse to such treatment is the most practical option for many PD opiate users, a potential criticism being that this does not directly address the PD problems.

The Behavioral Genetics of Personality Disorder

Behavioral genetics research has opened a new window on understanding personality disorder. The earliest studies were focused on establishing the relative contributions of genes and the environment in these disorders. Although these studies provided solid evidence of the importance of genetic and environmental influences on personality disorder and showed that all aspects of personality disorder are subject to genetic influence, heritability studies are limited because they are not helpful in explicating causal mechanisms. More recent research has focused on the relative contributions of the covariation of personality disorder diagnoses and traits, which allows one to examine etiological relationships. These developments are leading to major changes in ideas about what constitutes the environment and nature of the interplay between genes and environment. The present review examines major themes in this growing body of research in the context of current issues in the personality disorders.

A genetic factor explains most of the variation in the psychopathic personality

The psychopathic personality can be conceptualized as three interrelated dimensions, (a) an interpersonal style of glibness, grandiosity, and manipulation; (b) an affective disposition of callousness, lack of empathy, and unemotionality; and (c) a behavioral/lifestyle dimension of impulsivity, need for stimulation, and irresponsibility, underpinning a higher order construct, psychopathic personality. The authors used a self-report questionnaire (The Youth Psychopathic Traits Inventory) to study the importance of genetic and environmental influences on psychopathic personality traits in a sample of 1,090 monozygotic and dizygotic twin pairs, aged 16-17 years. Results showed a strong genetic influence behind the higher order "psychopathic personality" factor, underpinned by the three psychopathic personality dimensions. Over and above the effects to the higher order factor, significant unique genetic influences were also found in the callous/unemotional and in the impulsive/irresponsible dimension, but not in the grandiose/manipulative dimension. The authors propose that this latent psychopathic personality factor is a meaningful target for future etiological research.

Personality in young adults who are born preterm

INTRODUCTION

Very preterm birth (VPT; <33 weeks' gestation) is associated with later neuromotor and cognitive impairment, reduced school performance, and psychiatric morbidity. Several follow-up studies have demonstrated increased anxiety and social rejection and reduced self-esteem in preterm children and adolescents, but few studies have examined the effects of preterm birth on adult personality.

METHODS

We assessed 108 VPT individuals and 67 term-born controls at ages 18 to 19 years with the Eysenck Personality Questionnaire-Revised, short form (EPQ-RS). This questionnaire rates 3 dimensions of personality: extraversion (sociability, liveliness, sensation seeking); neuroticism (anxiety, low mood, low self-esteem); and psychoticism (coldness, aggression, predisposition to antisocial behavior). A fourth scale, "lie," which measures dissimulation, is also derived.

RESULTS

VPT individuals had significantly lower extraversion scores, higher neuroticism scores, and higher lie scores than term-born controls, after controlling for age at assessment and socioeconomic status. P scores were not significantly different between the 2 groups. There was a gender difference in that the increased neuroticism and decreased extraversion scores were accounted for mainly by VPT females. Associations between EPQ-RS scores and neonatal status, adolescent behavioral ratings, and body size at 18 to 19 years were assessed by using Kendall partial correlations, correcting for age at assessment and socioeconomic status. Gestational age, indices of neonatal hypoxia, and neonatal ultrasound ratings were not correlated with EPQ-RS scores. Birth weight was weakly associated with increased lie scores. Rutter Parents' Scale score, a measure of adolescent psychopathology, was associated with an increased neuroticism score. Poor social adjustment in adolescence was associated with an increased lie score. Height and weight at 18 to 19 years were not associated with EPQ-RS, but reduced occipitofrontal circumference was associated with both decreased extraversion and increased lie scores.

CONCLUSIONS

Young adults who are born VPT have different personality styles from their term-born peers. This may be associated with an increased risk of psychiatric difficulties.

Personality disorders in a total population twin cohort with eating disorders

Findings regarding the occurrence of personality disorders (PDs) in eating disorders (EDs) have been contradictory. Most previous studies have been clinic-based. The aims of the current study were to assess the prevalence of PD in ED in a population-based twin group and to establish the distribution of PD in three subgroups of ED. A two-step screening and diagnostic study of ED was performed in a large Danish twin population. Axis I and axis II DSM-III-R and DSM-IV ED diagnoses were made on the basis of results obtained at clinical investigations and interviews. Forty-nine percent of the participants with ED had at least one PD, compared to 26% in those with no ED (P <.001). Cluster C PD was the most common type of PD in all subgroups of ED, and cluster B PD was found only in participants with bulimic symptoms. Genetic factors appeared to contribute significantly to the variance of cluster C PD in ED, which was evaluated as a possibly important background factor in ED.

Is borderline personality disorder part of the bipolar spectrum?

In recent years, advances in the areas of both bipolar and borderline personality disorders have generated considerable interest in the clinical interface between these two conditions. Developments in the study of the neurobiology of borderline personality disorder suggest that many patients with this diagnosis have etiological features in common with those diagnosed with bipolar disorders. This claim is supported by new insights into the phenomenology of both disorders and by evidence that mood stabilizers are efficacious in the pharmacological management of borderline patients. This area of research is an important one because of the considerable morbidity and public health costs associated with borderline personality disorder. Since borderline patients can be so challenging to care for, it may be that a reframing of the disorder as belonging to the broad clinical spectrum of bipolar disorders holds benefits for patients and clinicians alike.

Schizotaxia: current status and future directions

Schizophrenia is a biologic disorder whose etiology involves a combination of genetic and environmental risk factors. In this review, the authors update the conceptual basis of schizotaxia, consider evidence for its validity, and look toward its likely evolution in the future.

Toward a molecular architecture of personality

Epidemiological studies provided a large body of evidence that personality dimensions are influenced by genetic factors and that the genetic component is highly complex, polygenic, and epistatic. However, consistent findings on the genetic basis of personality have yet remained sparse. In recent years, molecular genetics has begun to identify specific genes coding in particular for components of the serotonergic and dopaminergic neurotransmitter systems representing quantitative trait loci (QTLs) for behavioral traits. The QTL concept suggests that complex traits are not attributable to single genes. According to this polygenic model, the genetic basis of personality and behavior and its pathological variations thus results from additive or nonadditive interactions of various genes. As the number of suitable candidate genes constantly increases, the QTL model provides a reasonable explanation for the genetic basis of personality and its disorders. In this review, the current knowledge on the impact of a large number of candidate gene polymorphisms (e.g. variations in serotonin and dopamine receptor and serotonin transporter genes) on personality and temperament is summarized. Additionally, investigations of gene-gene and gene-environment interactions in humans and animals, which currently intensify the identification of genes that underlie behavioral variations, are examined. The findings converge on the notion that a probabilistic rather than deterministic impact of genes on the expression of behavior will contribute to the demystification of behavioral disorders.

Understanding predisposition to schizophrenia: toward intervention and prevention

OBJECTIVE

Early intervention to prevent schizophrenia is one of the most important goals of schizophrenia research. However, the field is not yet ready to initiate trials to prevent prodromal or psychotic symptoms in people who are at risk for developing the disorder. In this paper, we consider some of the major obstacles that must be studied before prevention strategies become feasible.

METHOD AND RESULTS

One of the most important hurdles is the identification of a syndrome or set of traits that reflects a predisposition to schizophrenia and that might provide potential targets for intervention. In a recent reformulation of Paul Meehl's concept of schizotaxia, we integrate research findings obtained over the last 4 decades to propose a syndrome with meaningful clinical manifestations. We review the conceptualization of this syndrome and consider its multidimensional clinical expression. We then describe preliminary research diagnostic criteria for use in adult, nonpsychotic, first-degree relatives of patients diagnosed with schizophrenia, based on negative symptoms and neuropsychological deficits. We follow this with evidence supporting the validity of the proposed syndrome, which mainly includes social dysfunction and response to a low dosage of one of the newer antipsychotic medications.

CONCLUSIONS

Continued progress toward the eventual initiation of prevention strategies for schizophrenia will include sustained efforts to validate the traits reflecting a predisposition to develop the disorder (for example, schizotaxia), follow-up studies to confirm initial findings, and the identification of potentially useful preventive interventions.

The borderline diagnosis II: biology, genetics, and clinical course

In Part I of this three-part article, consideration of the core features of BPD psychopathology, of comorbidity with Axis I disorders, and of underlying personality trait structure suggested that the borderline diagnosis might be productively studied from the perspective of dimensions of trait expression, in addition to that of the category itself. In Part II, we review the biology, genetics, and clinical course of borderline personality disorder (BPD), continuing to attend to the utility of a focus on fundamental dimensions of psychopathology. Biological approaches to the study of personality can identify individual differences with both genetic and environmental influences. The aspects of personality disorder that are likely to have biologic correlates are those involving regulation of affects, impulse/action patterns, cognitive organization and anxiety/inhibition. For BPD, key psychobiological domains include impulsive aggression, associated with reduced serotonergic activity in the brain, and affective instability, associated with increased responsivity of cholinergic systems. There may be a strong genetic component for the development of BPD, but it seems clear, at least, that there are strong genetic influences on traits that underlie it, such as neuroticism, impulsivity, anxiousness, affective lability, and insecure attachment. The course of BPD suggests a heterogeneous disorder. Predictors of poor prognosis include history of childhood sexual abuse, early age at first psychiatric contact, chronicity of symptoms, affective instability, aggression, substance abuse, and increased comorbidity. For research purposes, at least, biological, genetic, and prognostic studies all continue to suggest the need to supplement categorical diagnoses of BPD with assessments of key underlying personality trait dimensions and with historical and clinical observations apart from those needed to make the borderline diagnosis itself.

Differential effects of haloperidol and clozapine on [(3)H]cAMP binding, protein kinase A (PKA) activity, and mRNA and protein expression of selective regulatory and catalytic subunit isoforms of PKA in rat brain

The present study was undertaken to examine whether the mechanism of action of typical and atypical antipsychotics is related in their ability to regulate key phosphorylating enzyme of adenylyl cyclase-cAMP pathway, i.e., protein kinase A (PKA). For this purpose, regulatory (R) and catalytic (Cat) activities of PKA and expression of various isoforms of regulatory and catalytic subunits were examined in rat brain after single or chronic (21-day) treatment with haloperidol (HAL, 1 mg/kg) or clozapine (CLOZ, 20 mg/kg). It was observed that chronic but not acute treatment of CLOZ significantly decreased [(3)H]cAMP binding to the regulatory subunit of PKA as well as catalytic activity of PKA in particulate and cytosol fractions of the rat cortex, hippocampus, and striatum. In these fractions, CLOZ significantly decreased protein levels of selective RII alpha-, RII beta-, and Cat beta-subunit isoforms of PKA. These decreases were accompanied by decreases in their respective mRNA expression. In contrast, chronic but not acute treatment of HAL significantly increased [(3)H]cAMP binding and the catalytic activity of PKA in particulate and cytosol fractions of only the striatum brain area. In addition, chronic treatment of HAL significantly increased mRNA and protein levels of RII alpha- and RII beta-subunit isoforms in the striatum. None of the antipsychotics caused any change in the expression of the Cat alpha-, RI alpha-, or RI beta-subunit isoform. These results, thus, suggest that HAL and CLOZ differentially regulate PKA catalytic and regulatory activities and the expression of selective catalytic and regulatory subunit isoforms of PKA, which may be associated with their mechanisms of action.

Therapeutic effect of pirenzepine for clozapine-induced hypersalivation: a randomized, double-blind, placebo-controlled, cross-over study

The objective of this study was to investigate the efficacy of pirenzepine in the treatment of clozapine-induced hypersalivation. Pirenzepine is reported to counteract hypersalivation by its selective antagonistic activity on the M4-muscarinic receptor, which is stimulated by clozapine. Twenty patients with clozapine-induced hypersalivation underwent a random-order, double-blind, placebo-controlled, cross-over trial which lasted 8 weeks each for the pirenzepine and placebo investigations, with a 4-week washout period in between. The severity of hypersalivation was assessed using an objective measure: saliva production monitored through the diameter of wetted surface on tissue paper placed over the patient's pillow. Our study showed that pirenzepine had no significant therapeutic effect on hypersalivation compared with placebo, suggesting that hypersalivation induced by clozapine might have a neurobiological basis other than the M4-muscarinic receptor.

Privacy and the Human Genome Project

The Human Genome Project has raised many issues regarding the contributions of genetics to a variety of diseases and societal conditions. With genetic testing now easily conducted with lowered costs in nonmedical domains, a variety of privacy issues must be considered. Such testing will result in the loss of significant privacy rights for the individual. Society must now consider such issues as the ownership of genetic data, confidentiality rights to such information, limits placed on genetic screening, and legislation to control genetic testing and its applications. There is often a conflict between individual rights to privacy and the need for societal protection.

Are personality traits associated with cognitive disturbance in psychosis?

OBJECTIVE

Personality and cognition are often considered as disparate constructs, both in normal individuals and in those with a psychosis. The goal of the present study was to analyze the relationship between dimensions of personality and cognitive performance in individuals with psychosis.

METHODS

Sixty-one consecutively admitted patients with an acute psychotic episode were recruited for this study. Personality was assessed through a semistructured interview with a close relative using the Personality Assessment Schedule. A wide neuropsychological battery was applied, including attentional, executive, memory tasks and global cognition. Assessments took place when symptomatology was in remission.

RESULTS

Higher scores on a passive-dependent dimension were significantly associated with poorer memory performance. Similarly, higher levels for a schizoid dimension were significantly associated with poorer executive performance. The results remained significant after partialling out the effect of gender, psychopathological dimensions and drug status.

CONCLUSION

It is hypothesized that personality traits and cognitive performance are interrelated domains in psychosis.

Schizophrenia: vulnerability versus disease

One of the most important trends in the treatment of schizophrenia involves its early diagnosis and intervention. The ultimate goal of research is the prevention of the disorder, A major impediment to the development of prevention strategies, however, is that we do not yet know what the liability for schizophrenia is before the onset of psychosis. Consequently, early treatment attempts are focused on the “prodrome,” which involves the early symptoms of psychosis. In a companion paper, we recently suggested that prevention work should focus not only on the prodrome, but also on “schizotaxia,” which is a clinically meaningful condition that may reflect the vulnerability to schizophrenia in the absence of psychosis. Because schizotaxia can be assessed prior to the prodrome, studies of schizotaxia might lead to more effective prevention programs. We continue the characterization of schizotaxia in this paper by focusing on the etiological roots of schizotaxia, plus its likely neurodevelopmental course, clinical expression, and treatment. Finally, the importance of including neurobiological variables in the conceptualization and eventual diagnosis of schizotaxia is reviewed.

Genetic studies of substance abuse

Genetic studies of substance abuse indicate that variation in the risk for the disorder in the population is contributed by differences in both individual genotypes and environment. Recent developments in genetics raise the possibility of disentangling the complex system of genotype-environment interaction that determines the development of the individual behavioral phenotype. This paper reviews the concepts, methods and results pertaining to genetic investigation of substance abuse.

Serum levels of thyroid hormones as biological markers in a Swedish forensic psychiatric population

BACKGROUND

In a Swedish study, delinquent boys had high serum levels of triiodothyronine (T3). Furthermore, former delinquents, followed up after about 30 years, had T3 levels significantly related to repeated criminality. The aim of the present study was to shed further light on the relationship between the thyroid hormones and specific behaviors and personality characteristics.

METHODS

Serum levels of T3 and free thyroxine (FT4) were measured in 61 nonpsychotic male subjects at forensic psychiatric examinations and 66 normal controls. Psychopathy was determined by means of the Psychopathy Checklist-Revised (PCL-R) and DSM-III-R, DSM-IV, and ICD-10 diagnoses.

RESULTS

The study population had high T3 and low FT4 values. Elevated T3 levels were related to type II alcoholism, Cluster B personality disorders, psychopathy as measured by the PCL-R, criminality, a diagnosis of a DSM-IV antisocial disorder, and an ICD-10 dissocial disorder. Serum levels of FT4 were negatively related to the same disorders and personality traits.

CONCLUSIONS

The results indicate an intimate relationship between T3 and FT4, and abuse and antisocial behavior. They emphasize the importance of further studies on T3 as a biological marker for abuse, social deviance, and repeated violent behavior.

Does childhood trauma cause personality disorders in adults?

OBJECTIVE

To examine the relationship between trauma in childhood and personality disorders in adulthood.

METHOD

A review of the literature was conducted.

RESULTS

The reported associations between trauma and personality pathology are illuminated by the following research findings: 1) personality is heritable; 2) only a minority of patients with severe personality disorders report childhood trauma; and 3) children are generally resilient, and traumatic experiences do not consistently lead to psychopathology.

CONCLUSIONS

The role of trauma in the personality disorders is best understood in the context of gene-environment interactions.

Schizotypal disorder: at the crossroads of genetics and nosology

The aim of this paper is to review the available evidence in support of the correctness of including the DSM-III/III-R schizotypal personality disorder (SPD) in the schizophrenia spectrum, to discuss the components that may account for the familial segregation of SPD, and to consider the implications for research and clinical use of this diagnostic category. The majority of the available data from genetic epidemiology studies, starting from probands with schizophrenia or with SPD, suggest that SPD is one of several phenotypes of liability for the schizophrenia spectrum. Recent twin studies suggest that the affect-constricted and eccentric aspects of SPD are the features that truly belong to the spectrum of schizophrenia, sharing important genetic influences. However, other components are more useful for the identification of SPD in clinical settings, and these may be the specific focus of treatment. The present categorization appears to be a reasonable trade-off for the purposes of both the investigator and the clinician, even though different components within SPD may have different origins and can be selectively emphasized according to the different aims involved.

A twin study of antisocial and neurotic symptoms in childhood

There is some evidence to suggest that the role of genetic and environmental influences may vary for different types of psychiatric symptoms in childhood. The aim of this study was to examine to what extent genetic and environmental factors influence parent-rated conduct and neurotic symptoms in childhood and adolescence, using data obtained from a systematically ascertained sample of twins (198 same sex pairs) aged between 8 and 16 years. For symptoms of antisocial behaviour, transmission could be explained entirely by shared environmental factors. Social class effects were also found to have a significant influence on antisocial behaviour, although these effects only accounted for a small proportion of the variance explained by shared environmental factors. In contrast, transmission of neurotic symptoms was best explained by additive genetic influences alone with no contribution from shared environment. Non-shared environmental factors accounted for a substantial component of the variation for both antisocial behaviour and neurotic symptoms.

Genetic and environmental influences on the covariation between hyperactivity and conduct disturbance in juvenile twins

Structural equation models were applied to the maternal ratings of 265 MZ and 163 DZ male-male, 347 MZ and 160 DZ female-female, and 262 male-female twin pairs, aged 8-16 years, who participated in the Virginia Twin Study of Adolescent Behavioral Development (VTSABD). Substantial additive genetic influences and contrast effects were found for hyperactivity, and additive genetic and shared environmental effects or positive comparison effects (particularly for the girls) for oppositional/ conduct disturbance. Bivariate model fitting showed that the covariation between hyperactivity and oppositional/conduct problems in both younger and older boys and girls is almost entirely attributable to genetic factors. However, whereas in the younger males and females the same set of genes explain all the variation in hyperactivity and conduct disturbance, in the older cohort at least some of the genetic effects are behavior- and gender-specific.

Mating assortment and the liability to substance abuse

Assortative mating can exert a profound influence on the phenotypic composition of the population since it may result in an increase in the frequency of the genotypes associated with extreme phenotypes. Applied to the risk for a disorder such as substance abuse, this would mean a possibility for an increase in the risk and severity of the disorder in consecutive generations. This paper reviews the theoretical and empirical literature on mechanisms related to mate resemblance for the liability to substance abuse, sources and consequences of such resemblance, and suggests directions for further research.

A comparison of DSM-III-R and ICD-10 personality disorder criteria in an out-patient population

This study reports the results of a comparison of DSM-III-R and ICD-10 personality disorder criteria by application of both sets of criteria to the same group of patients. Despite the clinical relevance of these disorders and the need for reliable diagnostic criteria, such a comparison has not previously been reported. DSM-III-R and ICD-10 have converged in their classification of personality disorders, but some important differences between the two systems remain. Personality disorder diagnoses from both systems were obtained in 52 out-patients, using the Standardized Assessment of Personality (SAP), a brief, informant-based interview which yields diagnoses in both DSM-III-R and ICD-10. For individual personality disorder diagnoses, agreement between systems was limited. Thirty-four subjects received a personality disorder diagnosis that had an equivalent form in both systems, but only 10 subjects (29%) received the same primary diagnosis in each system. There was a difference in rate of diagnosis, with ICD-10 making significantly more personality disorder diagnoses. The lower diagnostic threshold of the ICD-10 contributed most of this effect. Further modifications in ICD-10 Diagnostic Criteria for Research (DCR) and DSM-IV to the personality disorder category have been considered. The omission in DSM-IV of three categories unique to that system and the raising of the threshold in ICD-10 DCR, do seem to have been helpful in promoting convergence.

Additive effects, but no synergistic interaction of stressful life-events and genetic loading in affective disorders

Life-event research as well as neurobiological findings point to the relevance of adverse stress for the pathogenesis of affective disorders. The well established genetic root might be related to the sensitivity to stress. In concordance, recent studies showed a synergistic interaction between genetic loading and life-events concerning the precipitation of depression, i.e. there might exist a genetic sensitization to the adverse effects of stressors. The present investigation, using information extracted from 877 case records, did not reveal a synergistic interaction concerning the age at onset and the mean frequency and duration of episodes.

Familial aggregation of phonological disorders: results from a 28-year follow-up

This investigation is a follow-up to a longitudinal speech and educational outcome study involving approximately 400 normally developing children that was initiated in 1960. From this database, two groups of subjects (now aged 32-34), their spouses, and all of their offspring over the age of 3:0 (years:months) completed a battery of cognitive-linguistic and interview measures. One group (probands) consisted of 24 adults with a documented history of a moderate phonological-language disorder that persisted through at least the end of the first grade. The other group (controls) consisted of 28 adults who were known to have had normal articulation abilities as children. Results of this study demonstrated that, in comparison to the children of controls, the children of the proband subjects performed significantly more poorly on all tests of articulation and expressive language functioning and were significantly more likely to have received articulation treatment. There was, however, no evidence that specific misarticulations or phonological processes traveled within proband families. These results are in agreement with those of most previous family studies that have demonstrated an increased rate of occurrence of speech-language disorders of unknown origin in families including a first-degree relative who is similarly affected.

Personality and trait disturbances in an adult mental retardation population: significance for psychiatric management

The authors demonstrate the high prevalence of personality disorders in 384 intellectually impaired individuals examined in both community and institutional settings in southwestern Ontario, Canada. The relationship of specific clusters of personality disorders to later onset of psychiatric disorders in intellectually impaired individuals is suggested. New approaches to the management of personality disorders are noted utilizing clinical case studies. Differences and similarities in nomenclature in American and International diagnostic classifications are illustrated in this study. The use of a detailed longitudinal and cross-sectional collection of biological, social and standardized personality schedules is demonstrated as feasible in this special population.

The genetic epidemiology of self-esteem

BACKGROUND

Previous studies on self-esteem have focused exclusively on its psychosocial determinants. The goal of the present study is to clarify genetic v. environmental determinants of self-esteem.

METHOD

Participants were Caucasian women sampled from the Virginia Twin Register: 363 pairs of MZ and 238 pairs of DZ twins were available from the first wave of the study, and 430 pairs of MZ and 308 pairs of DZ twins from the second. Self-esteem was assessed with the Rosenberg's Self-Esteem Scale.

RESULTS

Using univariate twin analyses of self-esteem and a repeated measurement twin model, we found that self-esteem is a moderately heritable trait (heritability = 52% in the repeated measurement model); environmental influences are also very important, and are probably mostly not shared by members of a twin pair.

CONCLUSIONS

Aetiological models of self-esteem which examine only psychosocial factors are incomplete; genetic factors need to be integrated.

A twin study of depressive symptoms in childhood

BACKGROUND

Although depression in childhood appears to be familial, transmission of symptoms could be genetic or environmental. Twin studies enable us to separate these effects. Our aim was to assess the importance of genetic and environmental factors on depressive symptoms during childhood and adolescence in an epidemiological sample of twins.

METHOD

Questionnaires (including the Mood and Feelings questionnaire) were mailed to a systematically ascertained sample (411 twin pairs) aged between 8 and 16 years. The overall response rate was 77%.

RESULTS

Data for the whole sample were best explained by an additive genetic model, with heritability of depressive symptom scores estimated at 79%. However, on splitting the sample, symptoms in children (aged 8 to 11) could be explained by shared environmental factors only, while symptoms in adolescents (aged 11 to 16) remained highly heritable.

CONCLUSIONS

The results suggest that although depressive symptoms appear to be largely heritable, the influence of genetic and environmental factors may vary with age.

Heredity in personality disorders--an overview

The concept of personality disorders is based on deviant personality traits in both the DSM-III-R and ICD-10 classifications. A diagnosis of personality disorder can be made reliably with structured interviews. Many individuals are diagnosed with more than one personality disorder, and other mental disorders are often found at the same time. Among the 11 personality disorders in DSM-III-R, only the schizotypal, borderline, and antisocial have been examined to any considerable extent for gene effects. The problems of studying heredity are here demonstrated for borderline and antisocial personality disorders. Recommendations are given as to strategies for further study of heredity in personality disorders.