Schizotypal personality traits in Gilles de la Tourette syndrome

The Transdiagnostic Relevance of Self-Other Distinction to Psychiatry Spans Emotional, Cognitive and Motor Domains

Self-other distinction refers to the ability to distinguish between our own and other people's physical and mental states (actions, perceptions, emotions etc.). Both the right temporo-parietal junction and brain areas associated with the human mirror neuron system are likely to critically influence self-other distinction, given their respective contributions to theory of mind and embodied empathy. The degree of appropriate self-other distinction will vary according to the exact social situation, and how helpful it is to feel into, or remain detached from, another person's mental state. Indeed, the emotional resonance that we can share with others affords the gift of empathy, but over-sharing may pose a downside, leading to a range of difficulties from personal distress to paranoia, and perhaps even motor tics and compulsions. The aim of this perspective paper is to consider how evidence from behavioral and neurophysiological studies supports a role for problems with self-other distinction in a range of psychiatric symptoms spanning the emotional, cognitive and motor domains. The various signs and symptoms associated with problematic self-other distinction comprise both maladaptive and adaptive (compensatory) responses to dysfunction within a common underlying neuropsychological mechanism, compelling the adoption of more holistic transdiagnostic therapeutic approaches within Psychiatry.

A Comprehensive Review of Tic Disorders in Children

Tics are characterized by sudden, rapid, recurrent, nonrhythmic movement or vocalization, and are the most common movement disorders in children. Their onset is usually in childhood and tics often will diminish within one year. However, some of the tics can persist and cause various problems such as social embarrassment, physical discomfort, or emotional impairments, which could interfere with daily activities and school performance. Furthermore, tic disorders are frequently associated with comorbid neuropsychiatric symptoms, which can become more problematic than tic symptoms. Unfortunately, misunderstanding and misconceptions of tic disorders still exist among the general population. Understanding tic disorders and their comorbidities is important to deliver appropriate care to patients with tics. Several studies have been conducted to elucidate the clinical course, epidemiology, and pathophysiology of tics, but they are still not well understood. This article aims to provide an overview about tics and tic disorders, and recent findings on tic disorders including history, definition, diagnosis, epidemiology, etiology, diagnostic approach, comorbidities, treatment and management, and differential diagnosis.

Tics and Tourette Syndrome

PURPOSE OF REVIEW

The purpose of this article is to present current information on the phenomenology, epidemiology, comorbidities, and pathophysiology of tic disorders and discuss therapy options. It is hoped that a greater understanding of each of these components will provide clinicians with the necessary information to deliver thoughtful and optimal care to affected individuals.

RECENT FINDINGS

Recent advances include the finding that Tourette syndrome is likely due to a combination of several different genes, both low-effect and larger-effect variants, plus environmental factors. Pathophysiologically, increasing evidence supports involvement of the cortical-basal ganglia-thalamocortical circuit; however, the primary location and neurotransmitter remain controversial. Behavioral therapy is first-line treatment, and pharmacotherapy is based on tic severity. Several newer therapeutic agents are under investigation (eg, valbenazine, deutetrabenazine, cannabinoids), and deep brain stimulation is a promising therapy.

SUMMARY

Tics, defined as sudden, rapid, recurrent, nonrhythmic motor movements or vocalizations, are essential components of Tourette syndrome. Although some tics may be mild, others can cause significant psychosocial, physical, and functional difficulties that affect daily activities. In addition to tics, most affected individuals have coexisting neuropsychological difficulties (attention deficit hyperactivity disorder, obsessive-compulsive disorder, anxiety, mood disorder, disruptive behaviors, schizotypal traits, suicidal behavior, personality disorder, antisocial activities, and sleep disorders) that can further impact social and academic activities or employment.

Social cognition and self-other distinctions in neuropsychiatry: Insights from schizophrenia and Tourette syndrome

Impairments in social cognition may reflect dysfunction of disorder specific or disorder general mechanisms. Although cross-disorder comparison may prove insightful, few studies have compared social cognition in different neuropsychiatric disorders. Parallel investigation of schizophrenia and Tourette syndrome (TS) is encouraged by similarities including the presence of problematic social behavior, echophenomena, emotional dysregulation and dopamine dysfunction. Focusing on tests of social cognition administered in both disorders, this review aims to summarize behavioral, neurophysiological and neuroimaging findings, before exploring how these may contribute to clinical symptoms. Studies investigating social cognition (imitation, emotion recognition, and understanding of beliefs or intentions) in patients with schizophrenia or TS were identified through Web of Science and PubMed searches. Although findings indicate that social cognitive deficits are more apparent in schizophrenia, adults with TS can exhibit similar task performance to patients with paranoia. In both disorders, behavioral and neuroimaging findings raise the possibility of increased internal simulation of others' actions and emotions, in combination with a relative under-application of mentalizing. More specifically, dysfunction in neurobiological substrates such as temporo-parietal junction and inferior frontal gyrus may underlie problems with self-other distinctions in both schizophrenia and TS. Difficulties in distinguishing between actions and mental states linked to the self and other may contribute to a range of psychiatric symptoms, including emotional dysregulation, paranoia, social anhedonia and socially disruptive urges. Comparing different patient populations could therefore reveal common neuro-cognitive risk factors for the development of problematic social behaviors, in addition to markers of resilience, coping strategies and potential neuro-compensation mechanisms.

Major and minor life events, personality and psychopathology in children with tourette syndrome

Environmental, psychological, and biological interactions underlie many psychopathologies. Tourette's Syndrome (TS) has an obvious biological substrate but environmental factors and personality play substantial roles in its expression. We aimed to study the interrelationships between stressful life events, personality traits, tics, and comorbid disorders in children with TS. To this end, 132 children with TS and 49 healthy controls were recruited for the study. Major life events in the 12-months prior to testing and minor life events in the month prior to testing were retrospectively assessed using the Life Experiences Survey (LES) and the Brief Adolescent Life Events Scale (BALES), respectively. Personality was assessed with the Junior Temperament and Character Inventory (JTCI). Tics, obsessive compulsive symptoms, attention deficit and hyperactivity symptoms, anxiety, depression and aggression were assessed by self-report questionnaires and semi-structured interviews. We found that major life events correlated with the severity of tics expression and complexity, and comorbid psychopathology. Minor life events correlated with more severe symptomatology. High levels of harm avoidance were related to more obsessions, anxiety, and depression whereas high levels of self-directedness were protective. To conclude, TS expression in childhood should be understood as the result of an interaction between biological, personality and environmental factors.

Personality Profile of Male Adolescents With Tourette Syndrome: A Controlled Study

Tourette syndrome is a neurodevelopmental disorder characterized by multiple tics and commonly associated with behavioral problems, especially obsessive-compulsive disorder and attention-deficit hyperactivity disorder (ADHD). The presence of specific personality traits has been documented in adult clinical populations with Tourette syndrome but has been underresearched in younger patients. We assessed the personality profiles of 17 male adolescents with Tourette syndrome and 51 age- and gender-matched healthy controls using the Minnesota Multiphasic Personality Inventory-Adolescent version, along with a standardized psychometric battery. All participants scored within the normal range across all Minnesota Multiphasic Personality Inventory-Adolescent version scales. Patients with Tourette syndrome scored significantly higher than healthy controls on the Obsessiveness Content Scale only (P = .046). Our findings indicate that younger male patients with Tourette syndrome do not report abnormal personality traits and have similar personality profiles to healthy peers, with the exception of obsessionality traits, which are likely to be related to the presence of comorbid obsessive compulsive symptoms rather than tics.

Narcissistic vulnerability is a common cause for depression in patients with Gilles de la Tourette syndrome

The aim of this study was to assess for the first time different dimensions of narcissistic self-regulation in a large cohort of adult patients with Gilles de la Tourette syndrome (GTS) (n=50). From preliminary studies it is suggested that narcissistic personality trait and disorder, respectively, are relatively uncommon and occur in only 6-10% of GTS patients. In this study we used the Narcissism Inventory (NI), a 163-items questionnaire that measures four different dimensions of narcissism. The main result was that the prevalence of narcissism strongly depends on the subtype of narcissism: while the vulnerable narcissism ("threatened self" and "hypochondriac self") was common, the "classic narcissistic self" (grandiose narcissism) was rare. From our data an association between comorbid depression and increased values of the "threatened self" and comorbid OCD with increased values of the "hypochondriac self" is suggested. Narcissism correlated positively with the personality domain neuroticism and had a significantly negative impact on patients' quality of life. Therefore it can be speculated that vulnerable narcissism is - among several others - one cause for depression in patients with GTS. These findings may open new psychotherapeutic perspectives in the treatment of depression in patients with GTS.

Trichotillomania and personality traits from the five-factor model

OBJECTIVE

To examine whether personality traits have predictive validity for trichotillomania (TTM) diagnosis, pulling severity and control, and hair pulling style.

METHODS

In study 1, logistic regression was used with TTM cases (n=54) and controls (n=25) to determine if NEO Five-Factor Inventory (NEO-FFI) personality domains predicted TTM case vs. control classification. In study 2, hierarchical multiple regression was used with TTM cases (n=164) to determine whether NEO-FFI personality domains predicted hair pulling severity and control as well as focused and automatic pulling styles.

RESULTS

TTM case vs. control status was predicted by NEO-FFI neuroticism. Every 1-point increase in neuroticism scores resulted in a 10% greater chance of TTM diagnosis. Higher neuroticism, higher openness, and lower agreeableness were associated with greater pulling severity. Higher neuroticism was also associated with less control over hair pulling. Higher neuroticism and lower openness were associated with greater focused pulling. None of the personality domains predicted automatic hair pulling.

CONCLUSIONS

Personality traits, especially neuroticism, can predict TTM diagnosis, hair pulling severity and control, and the focused style of pulling. None of the personality traits predicted automatic pulling. Longitudinal studies are needed to determine whether personality variables predispose to TTM onset, impact disorder course, and/or result from hair pulling behavior.

Patients with Gilles de la Tourette syndrome have widespread personality differences

Only little is known about pathological personality traits in patients with Gilles de la Tourette syndrome (GTS). The aim of this study was to further investigate the prevalence of personality traits in adults with GTS. We used a variety of rating scales to assess not only personality traits, but also severity of tics, quality of life, and comorbidities (obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), depression), in a large group (n=50) of patients. Our major finding was that pathological personality traits are very common in patients with GTS encompassing a wide range of different personality traits, but most typically personality traits related to cluster C. Demand-anxious was the most common personality trait, while histrionic personality trait was absent. Patients' quality of life was more impaired by personality traits than comorbidities. Personality traits were more common in patients with comorbid OCD and depression, while comorbid ADHD had no influence. Our findings, therefore, corroborate the hypothesis that GTS plus OCD represents a more severe subtype of GTS, and support the assumption that OCD and depression, but not ADHD, are part of the GTS spectrum.

A personal 35 year perspective on Gilles de la Tourette syndrome: prevalence, phenomenology, comorbidities, and coexistent psychopathologies

This Series is a personal narrative of my experience with patients with Gilles de la Tourette syndrome and covers its definition and history since the first description in 1825. Controversy entered the prevalence debate early. Although originally considered very rare, in the 1980s, Tourette's syndrome was reported to be common. However, Tourette's syndrome has been shown to occur at a prevalence of about 0·85% to 1%. Tourette's syndrome is more common in the male population, more prominent during childhood, and usually improves, but does not disappear with age. Tourette's syndrome is considered less common in people of sub-Saharan black African, African-American, and American Hispanic ethnic origin. The phenomenology is similar worldwide, indicating a biological basis. The hallmark characteristics are multiple motor and one or more vocal/phonic tics. Other associated features include premonitory urges, a waxing and waning course, and to a much lesser degree, coprolalia. Comorbid disorders are common and are suggested to include obsessive-compulsive disorder and behaviours, attention deficit hyperactivity disorder, and autistic spectrum disorder. Coexistent psychopathologies are suggested to include depression and conduct and personality disorders. Importantly, I argue that Tourette's syndrome is not a unitary condition. Finally, I offer suggestions for future research.

Misophonia: current perspectives

Misophonia is characterized by a negative reaction to a sound with a specific pattern and meaning to a given individual. In this paper, we review the clinical features of this relatively common yet underinvestigated condition, with focus on co-occurring neurodevelopmental disorders. Currently available data on the putative pathophysiology of the condition can inform our understanding and guide the diagnostic process and treatment approach. Tinnitus retraining therapy and cognitive behavior therapy have been proposed as the most effective treatment strategies for reducing symptoms; however, current treatment algorithms should be validated in large population studies. At the present stage, competing paradigms see misophonia as a physiological state potentially inducible in any subject, an idiopathic condition (which can present with comorbid psychiatric disorders), or a symptomatic manifestation of an underlying psychiatric disorder. Agreement on the use of standardized diagnostic criteria would be an important step forward in terms of both clinical practice and scientific inquiry. Areas for future research include phenomenology, epidemiology, modulating factors, neurophysiological underpinnings, and treatment trials.

Tourette syndrome is associated with insecure attachment and higher aggression

This study explored the degree to which adult patients with Tourette syndrome (TS) exhibit particular attachment styles and the possible association between the underlying attachment dimensions and forms of aggression. Fifty-three TS patients (ages 17-72 years) and 54 matched healthy controls completed the Experiences in Close Relationships-Revised Scale (ECR-R) and the Aggression Questionnaire (AQ). The data were analysed with ANOVA F-tests, t-tests, and Pearson's correlation coefficient. TS patients showed significantly higher scores in relationship anxiety ( p < 0.001) and relationship avoidance ( p = 0.001) in the ECR-R and significantly higher aggression scores in the AQ ( p < 0.001). The total AQ score correlated significantly with the ECR-R dimension anxiety ( p < 0.001). These are the first findings on TS patients' attachment styles and anger symptoms. It remains unclear whether attachment anxiety and avoidance are risk factors for TS or whether the disorder itself induces attachment disorders. Prospective studies with detailed attachment interviews would help to explore this issue.

Tourette's syndrome and associated disorders: a systematic review

Objective: To compile data on Tourette's syndrome (TS), tics and associated disorders.Methods: A systematic review of the literature was conducted using the 5S levels of organization of healthcare research evidence (systems, summaries, synopses, syntheses, studies), based on the model described by Haynes. The search keywords were Tourette, tics and comorbidity, which were cross-referenced. Studies provided by publishers and articles being processed on July 31, 2013, were also included.Results: Of all studies retrieved during the search, 64 were selected because they analyzed the epidemiology, clinical features and etiopathogenesis of TS and its comorbidities. TS is classified as a hyperkinetic movement disorder, and at least 90% of the patients have neuropsychiatric comorbidities, of which attention deficit hyperactivity and obsessive-compulsive disorders are the most common. The syndrome is clinically heterogeneous and has been associated with a dysfunction of cortico-striatal-thalamic-cortical circuits involving various neurotransmitters. Although its genetic etiology has been widely studied, other factors may be important to understand this syndrome and its associated disorders.Conclusions: TS is a neurodevelopmental disorder that results from the impact of stress factors on a vulnerable biological substrate during the critical periods of neurodevelopment. The study of TS and its comorbidities may contribute, at different levels, to the understanding of several neuropsychiatric disorders of clinical and therapeutic relevance.

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.

Tourette syndrome and consciousness of action

BACKGROUND

Tourette syndrome (TS) is a neuropsychiatric disorder characterized by the chronic presence of multiple motor tics and at least one vocal/phonic tic since childhood. Tics typically change and vary in both intensity and severity over time, with remission and exacerbation common. In the vast majority of patients, tic expression is characteristically accompanied by discomforting bodily sensations, known as sensory phenomena or premonitory urges.

METHODS

We reviewed the existing literature on premonitory urges associated with the sense of voluntariness of action in TS.

RESULTS

Although the wish to move is perceived by the patient as involuntary, the decision to release the tic is often perceived by the patient as a voluntary capitulation to the subjective urge. Most patients with TS can exert a degree of control over the urge and constantly try to inhibit the movement. Based on these features, it has been suggested that tics performed in response to an urge to move should be classified as 'unvoluntary', as opposed to voluntary or involuntary acts. However, recent experimental data suggest that the brain areas involved in the generation of the wish to act show considerable overlap between healthy subjects and patients with TS.

DISCUSSION

The simultaneous presence of both voluntary and involuntary aspects in the expression of tic symptoms by patients with TS is consistent with the hypothesis that tics can have the same neurophysiologic substrate as voluntary acts, even though they are misperceived as being involuntary. This reinforces the view of TS as a hyperkinetic movement disorder primarily affecting the conscious experience of action.

EEG improvements with antiepileptic drug treatment can show a high correlation with behavioral recovery in children with ADHD

We investigated the relationship between neuropsychological disturbance, assessed using the global assessment of functioning (GAF) and the ADHD-rating scale (ADHD-RS), paroxysmal EEG abnormalities, and treatment with valproate sodium (VPA) in children with both attention deficit hyperactivity disorder (ADHD) and paroxysmal abnormality (PA). Participants with ADHD but without obvious epilepsy were recruited between April 1, 2003 and March 31, 2008. Paroxysmal abnormality was scored by measuring the spike frequency. Of 46 children, 16 showed PA; 3 of the 16 were excluded because no follow-up EEG was available. The EEG improved with VPA treatment in 5 of 8 patients with frontal PA and 3 of 5 patients with rolandic PA. While 83.3% of the patients with improvements in both assessments had frontal PA, only 16.7% had rolandic PA. The patients with frontal PA showed a significantly higher correlation between PA frequency and improvement in ADHD-RS compared with those with rolandic PA. In this study of children with ADHD, EEG improvement with antiepileptic drug treatment showed a high correlation with behavioral improvements as shown by ADHD-RS and GAF scores. However, this was not a population-based study, and the relative importance of detecting and treating PA in ADHD has yet to be determined.

A controlled study of personality and affect in Tourette syndrome

OBJECTIVE

Tourette syndrome (TS) can increase the likelihood of social and emotional difficulties which may shape an individual's personality and self-perception. We investigated personality and affect in patients with TS.

METHODS

Twenty-five adults with TS (2 with co-morbid obsessive compulsive disorder, 4 with co-morbid attention-deficit hyperactivity disorder and 4 with both co-morbidities), who were not clinically depressed, and 25 matched controls participated in the study. They completed the Ten-Item Personality Index, the Positive and Negative Affect Scale and the Beck Depression Inventory.

RESULTS

Adults with TS exhibited no differences from controls in reported emotional experience or depressive symptoms but did differ for four of the five assessed personality dimensions; extraversion, conscientiousness, openness and emotional stability. Individuals with pure TS (who had no co-morbid conditions) exhibited reduced extraversion and emotional stability compared to controls. Personality scores were not related to tic severity, yet lower emotional stability scores were associated with higher ratings of negative affect.

CONCLUSIONS

This study is limited by a restricted sample in terms of size and source. However, our findings indicate that in the absence of depression and common co-morbidities, people with TS differ from controls in indices of personality, which are linked to negative affectivity.

The psychopathological spectrum of Gilles de la Tourette syndrome

Gilles de la Tourette syndrome (GTS) holds a unique status as quintessentially neuropsychiatric condition at the interface between neurology (movement disorder) and psychiatry (behavioural condition). This is a reflection of the common observation that the vast majority of patients present with behavioural problems in association with the motor and vocal tics which define GTS. The present article focuses on the relationship between GTS and obsessive-compulsive disorder (OCD), attention-deficit and hyperactivity disorder (ADHD), affective disorders (both major depression and bipolar affective disorder), and personality disorders. Over the last decade, converging lines of research have pointed towards the concept of a 'GTS spectrum', encompassing motor phenomena and behavioural symptoms, with important implications for the clinical management of patients.

Surgical treatment of Tourette syndrome

In severely affected, treatment resistant patients with Tourette syndrome (TS) new therapeutic strategies are urgently needed. Since 1999, 34 studies including more than 90 patients have been performed to investigate the efficacy and safety of deep brain stimulation (DBS) in the treatment of tics resulting in the vast majority of patients in an improvement of tics and in some patients even of comorbidities. Both surgery-related (e.g., bleeding, infection) and stimulation-related adverse events (e.g., loss of energy, blurred vision) seem to occur only in a minority of patients and not to cause significant impairment, respectively. Since randomized controlled studies including a larger number of patients are still lacking, up to now, no definite conclusion can be drawn. Therefore, at present time DBS is recommended only in adult, treatment resistant, and severely affected patients. However, most experts have no doubt that DBS is indeed effective in the treatment of tics. Future studies should aim to identify which target in which patient is optimal depending on the individual symptomatology.

Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder consisting of multiple motor and one or more vocal/phonic tics. TS is increasingly recognized as a common neuropsychiatric disorder usually diagnosed in early childhood and comorbid neuropsychiatric disorders occur in approximately 90% of patients, with attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD) being the most common ones. Moreover, a high prevalence of depression and personality disorders has been reported. Although the mainstream of tic management is represented by pharmacotherapy, different kinds of psychotherapy, along with neurosurgical interventions (especially deep brain stimulation, DBS) play a major role in the treatment of TS. The current diagnostic systems have dictated that TS is a unitary condition. However, recent studies have demonstrated that there may be more than one TS phenotype. In conclusion, it appears that TS probably should no longer be considered merely a motor disorder and, most importantly, that TS is no longer a unitary condition, as it was previously thought.

Tourette syndrome and other tic disorders

Tic disorders, including Tourette syndrome, are an intriguing group of paroxysmal movement abnormalities that begin in childhood, have a fluctuating course, are capable of causing psychosocial and physical problems, and often improve by early adulthood. These disorders are frequently associated with a variety of comorbid problems whose negative effects may exceed those of tics. Therapy is strictly symptomatic and usually includes educational, behavioral, and a variety of pharmacological therapies. Although there is strong evidence supporting an inherited basis, the precise genetic abnormality remains unknown. A proposed poststreptococcal autoimmune etiology remains controversial. Pathophysiologically, tics appear to arise from an alteration within cortico-striatal-thalamo-cortical circuits, but the definitive site is unknown. Evidence supports an abnormality of synaptic neurotransmission, likely involving the dopaminergic system.

Tourette syndrome and comorbid early-onset schizophrenia

OBJECTIVE

A study of the shared phenomenology between Tourette syndrome (TS) and schizophrenia.

METHOD

An illustrative case report is presented. We used a chart review of 399 clinically ascertained patients with TS to identify 10 cases meeting criteria for schizophrenia. From our 10 patients, salient clinical characteristics were then tabulated. We then extracted similar clinical characteristics from a previously published series of patients with comorbid TS and schizophrenia in order to combine cases and allow for a comparison between childhood-onset schizophrenia (COS), adolescent-onset schizophrenia (AdolOS), and adult-onset schizophrenia (AduOS) cases in these groups.

RESULTS

We found 10 cases of schizophrenia (all were males) in the 399 TS patients for a prevalence rate of 2.5% (95% CI 0.96-4.04). Mean age of tic onset for TS diagnostic criteria ranged from 2-14 years with a mean of 8.2 years. The mean age of diagnosis for schizophrenia was 14.2 (range 9-23 years). We found six cases of schizophrenia with onset of positive psychotic symptoms by 13 years of age, two cases with onset after 13 years of age and before 18 years of age, and two cases with onset after 18 years of age. Attention deficit hyperactivity disorder was present at a higher rate (70%) than one would expect in a clinically ascertained group of patients with TS. Comparison between COS, AdolOS and AduOS in our pooled cases noted a sex bias skewed toward males. Catatonic symptoms may be more likely in child or adolescent onset cases and negative symptoms more likely in AduOS cases.

CONCLUSIONS

The 2.5% prevalence of schizophrenia in our TS sample exceeds the 1% expected rate of schizophrenia in the general population (chi-square=9.14; P=.0025). The six cases of COS (before 13 years of age) exceeds the expected rate of 1-2 per 100,000 (chi-square=4499; P=.0001). The 752-fold increase in observed rates of comorbid TS and COS over expected rates suggests a role for unknown common underlying etiologic factors. Based on clinical features, patients with TS and comorbid COS, AdolOS, or AduOS do not have different conditions. We conclude with suggestions for further research.

A risk PRODH haplotype affects sensorimotor gating, memory, schizotypy, and anxiety in healthy male subjects

BACKGROUND

Significant associations have been shown for haplotypes comprising three PRODH single nucleotide polymorphisms (SNPs; 1945T/C, 1766A/G, 1852G/A) located in the 3' region of the gene, suggesting a role of these variants in the etiopathogenesis of schizophrenia. We assessed the relationship between these high-risk PRODH polymorphisms and schizophrenia-related endophenotypes in a large and highly homogeneous cohort of healthy males.

METHODS

Participants (n = 217) were tested in prepulse inhibition (PPI), verbal and working memory, trait anxiety and schizotypy. The QTPHASE from the UNPHASED package was used for the association analysis of each SNP or haplotype data. This procedure revealed significant phenotypic impact of the risk CGA haplotype. Subjects were then divided in two groups; levels of PPI, anxiety, and schizotypy, verbal and working memory were compared with analysis of variance.

RESULTS

CGA carriers (n = 32) exhibited attenuated PPI (p < .001) and verbal memory (p < .001) and higher anxiety (p < .004) and schizotypy (p < .008) compared with the noncarriers (n = 185). There were no differences in baseline startle, demographics, and working memory. The main significant correlations were schizotypy x PPI [85-dB, 120-msec trials] in the carriers and schizotypy x anxiety in the entire group and the noncarriers but not the carriers group.

CONCLUSIONS

Our results strongly support PPI as a valid schizophrenia endophenotype and highlight the importance of examining the role of risk haplotypes on multiple endophenotypes and have implications for understanding the continuum from normality to psychosis, transitional states, and the genetics of schizophrenia-related traits.