Empathy and schizotypy following acquired brain damage.

OBJECTIVES: Acquired brain damage is associated with a reduced capacity for empathy, and emerging evidence indicates that there may also be elevated levels of schizotypy. However, although a relationship between schizotypy and empathy has been identified in other populations, no study to date has tested whether this relationship is also evident following acquired brain damage, and if so, whether it is specific to certain types of brain damage, or specific types of empathy. METHODS: People with acquired brain damage restricted to either frontal (N = 18) or non-frontal (N = 24) neural structures and demographically matched controls (N = 48) completed an assessment of schizotypy and a measure of empathy that differentiated between cognitive, emotional, and social skills empathy. RESULTS: Relative to the control group, people with frontal and non-frontal brain injuries reported elevated schizotypy, with the frontal group also reporting lower social skills empathy. Only in the frontal group was there support for an association between schizotypy and empathy, and this was specific to the social skills component of empathy. CONCLUSIONS: Schizotypy levels are elevated following brain damage, and frontal brain injury is linked to greater difficulties with the social skills component of empathy. Schizotypy appears to be an important consideration when understanding the link between empathy and frontal brain damage, with higher schizotypy levels associated with reduced social skills empathy in this population. Future research is now needed to establish whether problems with more implicit aspects of social understanding are relevant to understanding the relationship between schizotypy and poor social behavioural outcomes identified in other clinical groups that present with frontal brain damage. PRACTITIONER POINTS: People with an acquired brain injury experience deficits in empathic processing as well as elevated levels of schizotypal traits. Schizotypy levels and social skills empathy were inversely related in people who had experienced a frontal acquired brain injury, suggesting that schizotypy might be important for understanding social skill difficulties in this particular population. These findings highlight the potential benefit of including social cognitive assessments and schizotypy measures in standard neuropsychological assessment batteries.

Schizotypal traits are associated with sleep spindles and rapid eye movement in adolescence.

Research suggests an association between schizophrenia and a decrease in sleep spindle activity, as well as a change in sleep architecture. It is unknown how the continuum of psychotic symptoms relates to different features in the sleep electroencephalogram. We set out to examine how sleep architecture and stage 2 spindle activity are associated with schizotypy in a healthy adolescent population. The participants in our study (n = 176, 61% girls) came from a community-based cohort. Schizotypal traits were evaluated using the Schizotypal Personality Scale (STA) in early adolescence (mean age 12.3 years, SD = 0.5) and the participants underwent ambulatory overnight polysomnography at mean age 16.9 years (SD = 0.1). Sleep was scored in 30-s epochs into stages 1, 2, 3 and rapid eye movement (REM) sleep. Stage 2 spindles were detected using an automated algorithm. Spindle analyses from central and frontal derivations included spindle duration and density for slow (10-13 Hz) and fast (13-16 Hz) ranges. Covariates included sex and age. Those with the highest STA scores had a higher percentage of REM (B = 2.07 [95% CI, 0.17, 4.0]; p = .03) than those with the lowest scores. Those with the highest scores had shorter spindle duration, as derived from the frontal regions, and a slower oscillation range (B = -0.04 [95% CI, -0.07, -0.01]; p = .023) than those with the lowest scores. We conclude that high levels of schizotypy characteristics measured in early adolescence may be associated with distinguished features of sleep architecture, namely with spindle morphology and a higher proportion of REM sleep.

A longitudinal twin study of cluster A personality disorders.

BACKGROUND: While cluster A personality disorders (PDs) have been shown to be moderately heritable, we know little about the temporal stability of these genetic risk factors. METHOD: Paranoid PD (PPD) and schizotypal PD (STPD) were assessed using the Structured Interview for DSM-IV Personality in 2793 young adult twins from the Norwegian Institute of Public Health Twin Panel at wave 1 and 2282 twins on average 10 years later at wave 2. Using the program Mx, we fitted a longitudinal latent factor model using the number of endorsed criteria for PPD and STPD. RESULTS: The stability over time of the criteria counts for PPD and STPD, estimated as polychoric correlations, were +0.34 and +0.40, respectively. The best-fit longitudinal model included only additive genetic and individual-specific environmental factors with parameter estimates constrained to equality across the two waves. The cross-wave genetic and individual-specific environmental correlations for a latent cluster A factor were estimated to equal +1.00 and +0.13, respectively. The cross-time correlations for genetic and environmental effects specific to the individual PDs were estimated at +1.00 and +0.16-0.20, respectively. We found that 68% and 71% of the temporal stability of PPD and STPD derived, respectively, from the effect of genetic factors. CONCLUSION: Shared genetic risk factors for two of the cluster A PDs are highly stable in adults over a 10-year period while environmental risk factors are relatively transient. Over two-thirds of the long-term stability of the common cluster A PD liability can be attributed to genetic influences.

Schizotypal, Dissociative, and Imaginative Processes in a Clinical OCD Sample.

OBJECTIVE: Previous research in a nonclinical sample has suggested that schizotypal, dissociative, and imaginative processes may play a role in obsessive-compulsive disorder (OCD) symptoms (Aardema & Wu, ). The present study aims to extend these findings in a clinical sample. METHOD: N = 75 adults (mean age = 37.99; 61.3% female), meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, diagnostic criteria for OCD completed a battery of self-report questionnaires measuring schizotypal, dissociative, and imaginative processes. RESULTS: Hierarchical regression analyses revealed inferential confusion and dissociation to be the strongest predictors of OCD symptoms, replicating and extending the findings by Aardema and Wu (). CONCLUSION: Results support the notion that inferential confusion and dissociation are important variables to consider in understanding symptoms of OCD independently from obsessive beliefs and negative mood states.

Impact of adverse life events on individuals with low and high schizotypy in a nonpatient sample.

The aims of this study were to gain a better understanding of adverse life events connected with the development of schizotypal personality traits and, also, to examine whether subclinical schizotypy has a relationship with vulnerability to traumatic intrusions and avoidance. In a cross-sectional design, 198 undergraduate students completed the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE), the Impact of Event Scale (IES), and Paykel's Life Events Scale, together with other relevant scales. The number of adverse life events was significantly related to overall schizotypy measured by O-LIFE scores and positive schizotypy measured by the Unusual Experiences (UnEx) subscale. The subjective severity of life events was significantly related to Cognitive Disorganization (CogDis). Measures of positive schizotypy (UnEx and CogDis) were significantly related to the scores on the IES and on the intrusion and avoidance subscales, too. Adverse life events are associated with schizotypal personality traits, which contribute to a tendency for traumatic intrusions, even in a nonpatient sample.

Cumulative Environmental Risk in Early Life: Associations With Schizotypy in Childhood.

BACKGROUND AND HYPOTHESIS: Psychotic disorders are associated with a growing number of recognized environmental exposures. Cumulative exposure to multiple environmental risk factors in childhood may contribute to the development of different patterns of schizotypy evident in early life. Hypotheses were that distinct profiles of schizotypy would have differential associations with a cumulative score of environmental risk factors. STUDY DESIGN: We prospectively examined the relationship between 19 environmental exposures (which had demonstrated replicated associations with psychosis) measured from the prenatal period through to age 11 years, and 3 profiles of schizotypy in children (mean age = 11.9 years, n = 20 599) that have been established in population data from the New South Wales-Child Development Study. Multinomial logistic regression was used to examine associations between membership in each of 3 schizotypy profiles (true schizotypy, introverted schizotypy, and affective schizotypy) and exposure to a range of 19 environmental risk factors for psychosis (both individually and summed as a cumulative environmental risk score [ERS]), relative to children showing no risk. RESULTS: Almost all environmental factors were associated with at least 1 schizotypy profile. The cumulative ERS was most strongly associated with the true schizotypy profile (OR = 1.61, 95% CI = 1.52-1.70), followed by the affective (OR = 1.33, 95% CI = 1.28-1.38), and introverted (OR = 1.32, 95% CI = 1.28-1.37) schizotypy profiles. CONCLUSIONS: Consistent with the cumulative risk hypothesis, results indicate that an increased number of risk exposures is associated with an increased likelihood of membership in the 3 schizotypy profiles identified in middle childhood, relative to children with no schizotypy profile.

The differential effects of child abuse and posttraumatic stress disorder on schizotypal personality disorder.

OBJECTIVE: Previous findings suggest a relation between trauma exposure and risk for schizotypal personality disorder (SPD). However, the reasons for this relationship are not well understood. Some research suggests that exposure to trauma, particularly early trauma and child abuse, as well as posttraumatic stress disorder (PTSD) may play a role. METHODS: We examined subjects (n = 541) recruited from the primary care clinics of an urban public hospital as part of an National Institute of Mental Health-funded study of trauma-related risk and resilience. We evaluated childhood abuse with the Childhood Trauma Questionnaire and the Early Trauma Inventory and SPD with the Schedule for Nonadaptive and Adaptive Personality. We assessed for lifetime PTSD using the Clinician-Administered PTSD Scale. RESULTS: We found that of the 3 forms of abuse analyzed (emotional, physical, and sexual), only emotional abuse significantly predicted SPD (P < .001, R = 0.28) when all 3 abuse types were simultaneously entered into a regression model. Lifetime PTSD symptoms also significantly predicted SPD (P < .001, R = 0.26). Posttraumatic stress disorder was specifically predictive of 4 of the 8 SPD symptoms (P ≤ .001): excessive social anxiety, a lack of close friends or confidants, unusual perceptual experiences, and eccentric behavior or appearance. Using a Sobel test, we also found a partial mediation effect of PTSD on the relation between emotional abuse and SPD (z = 3.45, P < .001). CONCLUSIONS: These findings point to the important influence of emotional abuse on SPD and suggest that PTSD symptoms may provide a link between damaging childhood experiences and SPD symptoms in traumatized adults.

A developmental increase in allostatic load from ages 3 to 11 years is associated with increased schizotypal personality at age 23 years.

Although allostatic load has been investigated in mood and anxiety disorders, no prior study has investigated developmental change in allostatic load as a precursor to schizotypal personality. This study employed a multilevel developmental framework to examine whether the development of increased allostatic load, as indicated by impaired sympathetic nervous system habituation from ages 3 to 11 years, predisposes to schizotypal personality at age 23 years. Electrodermal activity to six aversive tones was recorded in 995 subjects at age 3 years and again at 11 years. Habituation slopes at both ages were used to create groups who showed a developmental increase in habituation (decreased allostatic load), and those who showed a developmental decrease in habituation (increased allostatic load). Children who showed a developmental increase in allostatic load from ages 3 to 11 years had higher levels of schizotypal personality at 23 years. A breakdown of total schizotypy scores demonstrated specificity of findings to cognitive-perceptual features of schizotypy. Findings are the first to document a developmental abnormality in allostasis in relation to adult schizotypal personality. The relative failure to develop normal habituation to repeated stressors throughout childhood is hypothesized to result in an accumulation of allostatic load and consequently increased positive symptom schizotypy in adulthood.

An investigation of the relationship between cortical connectivity and schizotypy in the general population.

Recent neuroimaging investigations have identified a relationship between psychotic symptoms in schizophrenia and abnormal brain connectivity. On the basis of the continuum model of psychosis, it was hypothesized that schizotypal traits in healthy control participants would be associated with relatively impaired frontotemporal white matter health as assessed using diffusion tensor imaging. Twenty-one participants (12 women and 9 men aged 18 to 58 years) completed the Schizotypal Personality Questionnaire (SPQ) and underwent diffusion-weighted magnetic resonance imaging scanning as part of a larger study. White matter integrity for the major association fibre tracts was assessed using standard measures of diffusivity, specifically fractional anisotropy (FA) and axial and radial diffusivity. A series of negative binomial regressions yielded significant relationships between reduced FA in seven white matter tracts and increased scores on the SPQ cognitive-perceptual factor. These findings are consistent with research relating brain connectivity to the positive symptoms of schizophrenia, suggesting that the neurobiological bases of schizotypal personality in healthy controls may be analogous to the neurobiological bases of schizophrenia spectrum disorders.

Vulnerability for psychopathology in Klinefelter syndrome: age-specific and cognitive-specific risk profiles.

AIM: Studying Klinefelter syndrome (KS) (47,XXY) can reveal insights into mechanisms of neurodevelopment. Our aim was to identify factors that influence risk for psychopathology in this syndrome, with a focus on age-specific and cognitive-specific risk profiles. METHODS: A total of 73 subjects with KS (25 children and 48 adults) and 93 age-matched controls (53 children and 40 adults) participated in the study. The discrepancy between verbal IQ (VIQ) and performance IQ (PIQ) was assessed using the Wechsler Intelligence Scales. IQ data were only measured in the Klinefelter group. All participants completed the Autism Questionnaire and Schizotypal Personality Questionnaire. RESULTS: Increased levels of autism traits and schizotypal traits were observed in individuals with KS, with schizotypal traits increasing with age. The VIQ < PIQ group (n = 33) showed significantly increased levels of autism traits compared to the PIQ < VIQ group (n = 12) and controls. The PIQ < VIQ group showed significantly increased levels of schizotypal traits compared to the VIQ < PIQ group and controls. The VIQ-PIQ discrepancy significantly correlated with schizotypal traits and autism traits, in opposite directions. CONCLUSION: Risk for psychopathology in KS may be age specific as well as dependent on cognitive profile. Relative deficits in verbal abilities seem more strongly associated with increased autism traits, whereas relative deficits in visuospatial abilities seem more strongly associated with increased schizotypal traits.

The Schizotypal Personality Questionnaire for Children (SPQ-C): Factor Structure, Child Abuse, and Family History of Schizotypy.

There is a relative dearth of research on features of schizotypal personality in children, in part due to lack of instrumentation. This study tests 5 competing models of the factor structure of the self-report Schizotypal Personality Questionnaire for Children (SPQ-C) and examines its relationship with a family history of schizotypal personality disorder (SPD), child abuse, and stability over time. Hypotheses were tested on 454 11- to 12-year-old schoolchildren and their caregivers. Confirmatory factor analyses supported a 3-factor structure of the SPQ-C (cognitive-perceptual, interpersonal, and disorganized). Test-retest stability was relatively robust over 3 months (r = .67), 6 months (r = .64), and 12 months (r = .55), with acceptable internal reliabilities (r = .84 to .91). Regarding construct validity, children with a biological family history of SPD had higher scores on all 3 factors (d =.51). Abused children had higher schizotypy scores (d = .55). A genetic × environment interaction was observed, with schizotypy highest in those with both a family history of schizotypy and also child abuse. Findings are the first in the child schizotypy field to document a gene × environment interaction and the independence of child abuse from confounding genetic influences. Results support the utility of the SPQ-C in future family and clinical studies of schizotypal personality and provide an avenue for much-needed and neglected research into the early antecedents of child schizotypal personality.

Do measures of schizotypal personality provide non-clinical analogues of schizophrenic symptomatology?

This study tested the assumption that measures of schizotypal personality provide non-clinical analogues of the heterogeneous symptomatology found in the schizophrenic disorder. The Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) was administered to schizophrenic patients and healthy controls, and measures of symptomatology from the Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS) were assessed in the patient group. Schizophrenic patients scored significantly higher than controls on O-LIFE measures of positive, negative and disorganised schizotypy, while no difference in Impulsive Nonconformity was observed. In the patient group, SAPS positive symptomatology was significantly correlated with O-LIFE positive schizotypy (Unusual Experiences) and Cognitive Disorganisation. However, there was no significant relationship between SAPS/SANS disorganisation and O-LIFE Cognitive Disorganisation, or between the SANS negative factor score and O-LIFE Introvertive Anhedonia. The results suggest that the O-LIFE is a valid tool for assessing schizotypal personality in both schizophrenic patients and healthy controls. However, while the O-LIFE measure of positive schizotypy may correspond with SAPS/SANS positive schizophrenic symptomatology, the negative and disorganised subscales may not be analogous to their SAPS/SANS counterparts. There is also evidence to question the acceptability of Impulsive Nonconformity as a true schizophrenia-like construct.

Early-life origins of schizotypal traits in adulthood.

BACKGROUND: Although schizotypal traits, such as anhedonia and aberrant perceptions, may increase the risk for schizophrenia-spectrum disorders, little is known about early-life characteristics that predict more pronounced schizotypal traits. AIMS: To examine whether birth size or several other early-life factors that have been previously linked with schizophrenia predict schizotypal traits in adulthood. METHOD: Participants of the Northern Finland 1966 Birth Cohort Study (n = 4976) completed a questionnaire on positive and negative schizotypal traits at the age of 31 years. RESULTS: Lower placental weight, lower birth weight and smaller head circumference at 12 months predicted elevated positive schizotypal traits in women after adjusting for several confounders (P<0.02). Moreover, higher gestational age, lower childhood family socioeconomic status, undesirability of pregnancy, winter/autumn birth, higher birth order and maternal smoking during pregnancy predicted some augmented schizotypal traits in women, some in men and some in both genders. CONCLUSIONS: The results point to similarities in the aetiology of schitzotypal traits and schizophrenia-spectrum disorders.

SPEM dysfunction and general schizotypy as measured by the SSQ: a controlled study.

BACKGROUND: SPEM dysfunction is a well-known phenomenon in schizophrenia. The principal aim of the present study was to examine whether SPEM dysfunction is already observable in subjects scoring high on a specific measure of schizotypy (SSQ General Schizotypy) that was selected because of its intimate relationship with schizophrenic prodromal unfolding. METHODS: Applying ANOVAs, we determined the relationship of subjects' scores on SSQ General Schizotypy and eye movements elicited by targets of different speed. We also examined whether there exists an association between our schizotypy measure and pupil size. RESULTS: We found more SPEM dysfunction in subjects scoring high on SSQ General Schizotypy than in subjects scoring average on that factor, irrespective of the speed of the target. No relationship was found between baseline pupil size and General Schizotypy. CONCLUSION: The present study provides additional evidence that SPEM dysfunction is associated with schizotypic features that precede the onset of schizophrenia and is already observable in general population subjects that show these features.

Neurodevelopmental factors associated with schizotypal symptoms among adolescents at risk for schizophrenia.

Schizophrenia has come to be viewed as a neurodevelopmental disorder that is characterized by genetic vulnerability, stressors during the prenatal period that may be marked by minor physical anomalies and neurobehavioral deficits that emerge in early development. Less is known about the neurodevelopmental origins of schizotypal personality symptoms. The present study examines schizotypal symptoms in Israeli adolescents (mean age = 16.79 years) who have not yet reached the developmental period during which first schizophrenic episode is most likely to emerge: 39 adolescent offspring of parents with schizophrenia, 39 offspring of parents with other psychiatric disorders, and 36 offspring of parents with no history of mental illness. The Semi-Structured Kiddie Interview for Personality Syndromes was used to assess cognitive-perceptual, interpersonal, and disorganized schizotypal symptoms. Interpersonal schizotypal symptoms were more prevalent in the schizophrenia offspring group than in the no-mental-illness offspring group. Among the schizophrenia offspring group, interpersonal, but not cognitive-perceptual, schizotypal symptoms were associated with minor physical anomalies, fine motor dyscoordination, and deficits in executive functioning during adolescence. Among young people whose parents did not have schizophrenia, cognitive-perceptual schizotypal symptoms were correlated with deficits in executive functioning. Adolescent schizotypal symptoms were associated with neurobehavioral symptoms measured during middle childhood in a subgroup of the sample that had been assessed prospectively. Finally, young people who had genetic risk for schizophrenia, minor physical anomalies, and neurobehavioral signs together were at markedly increased risk for symptoms of interpersonal schizotypal symptoms, compared to young people with one or none of these risk factors.

[Childhood of the schizophrenic patient]. / L'enfance du schizophrène.

We are able to identify the different risk factors involved in the development of the disorder from a study of the childhood of a schizophrenic patient. More specifically, we will define the perinatal risk factors: season and place of birth, viral exposure during pregnancy and obstetric complications. Developmental factors will also be discussed. Socialisation, language, psychomotor and cognitive development disorders are all developmental difficulties seen during the childhood of the schizophrenic patient. Finally we will finish by discussing a few psychosocial risk factors.

Winter birth, urbanicity and immigrant status predict psychometric schizotypy dimensions in adolescents.

BACKGROUND: Urbanicity, immigration and winter-birth are stable epidemiological risk factors for schizophrenia, but their relationship to schizotypy is unknown. This is a first examination of the association of these epidemiological risk factors with positive schizotypy, in nonclinical adolescents, controlling for a range of potential and known confounders. METHODS: We collected socio-demographics, life-style, family and school circumstances, positive schizotypy dimensions and other personality traits from 445 high school pupils (192 males, 158 immigrants) from 9 municipalities in Athens and Heraklion, Greece, which covered a range of host population and migrant densities. Using multivariate hierarchical linear regressions models, we estimated the association of schizotypy dimensions with: (1) demographics of a priori interest (winter-birth, immigrant status, urban characteristics), including family financial and mental health status; (2) factors resulting from principal component analysis (PCA) of the demographic and personal data; (3) factors resulting from PCA of the personality questionnaires. RESULTS: Adolescent women scored higher on schizotypy than men. High anxiety/neuroticism was the most consistent and significant predictor of all schizotypy dimensions in both sexes. In the fully adjusted models, urbanicity predicted magical thinking and unusual experiences in women, while winter-birth and immigration predicted paranoid ideation and unusual experiences respectively in men. CONCLUSIONS: These results support the continuum hypothesis and offer potential insights in the nature of risk conferred by winter-birth, urbanicity and immigration and the nature of important sex differences. Controlling for a wide range of potential confounding factors increases the robustness of these results and confidence that these were not spurious associations.

Coping Strategies Mediate the Effect of Stressful Life Events on Schizotypal Traits and Psychotic Symptoms in 22q11.2 Deletion Syndrome.

Converging evidence suggests that psychosis emerges from the complex interaction of genetic and environmental factors. Stressful life events (SLEs) play a prominent role in combination with coping strategies and with a dysfunctional hypothalamus-pituitary-adrenal axis (HPAA). It has been proposed that the framework of schizotypy might help disentangle the interaction between genetic and environmental factors in the pathogenesis of psychosis. Similarly, 22q11.2 deletion syndrome (22q11DS) is considered as a genetic model of psychosis vulnerability. However, SLE and coping strategies remain largely unexplored in 22q11DS. Moreover, the HPAA has not been systematically investigated in this population. Here, we explored the correlation between SLE, emotional coping strategies, schizotypal personality traits, subthreshold psychotic symptoms in a sample of 43 healthy controls (HCs) compared with 59 individuals with 22q11DS. In the latter, we also explored the correlation with pituitary volume as estimated from structural magnetic resonance imaging. We found that SLE and negative coping strategies were correlated with schizotypal personality traits in both HCs and 22q11DS, and with psychotic symptoms in the 22q11DS group only, whereas reduced pituitary volume correlated with general psychopathology. Moreover, dysfunctional coping mediated the effect of SLE on schizotypal personality traits and psychotic symptoms in 22q11DS. Our findings recapitulate evidence in nonsyndromic patients and confirm the central role of stress and coping in the pathogenesis of psychosis. More broadly, they highlight the importance of environmental factors in the pathway to psychosis in 22q11DS, suggesting a strong rationale for the implementation of stress and particularly coping-oriented interventions in this population.

Brain and behaviour in children with 22q11.2 deletion syndrome: a volumetric and voxel-based morphometry MRI study.

In people with velo-cardio-facial syndrome [or 22q11.2 deletion syndrome (22qDS)], a single interstitial deletion of chromosome 22q11.2 causes a wide spectrum of cognitive deficits ranging from global learning difficulties to specific cognitive deficits. People with 22qDS are also at high risk of developing attention-deficit/hyperactivity disorder and autism spectrum disorders in childhood, and schizophrenia in adolescence or adult life. However, the neurobiology of 22qDS, and the relationship between abnormalities in brain anatomy and behaviour, is poorly understood. Thus, we studied the neuroanatomy of 22qDS children using fully automated voxel-based morphometry (VBM) and manually traced single region-of-interest (ROI) analysis. Also, we investigated whether those brain regions that differed significantly between groups were related to behavioural differences within children with 22qDS. We compared the brain morphometry of 39 children and adolescents with 22qDS (mean age: 11 years, SD +/-3, IQ = 67, SD +/-10) and 26 sibling controls (mean age: 11 years, SD +/-3, IQ = 102, SD +/-12). Using VBM, we found, after correction for IQ, that individuals with 22qDS compared with controls had a significant reduction in cerebellar grey matter, and white matter reductions in the frontal lobe, cerebellum and internal capsule. Using single ROI analysis, we found that people with 22qDS had a significant (P < 0.05) reduction in bulk volume bilaterally in the occipital-parietal lobes, but a larger right caudate nucleus and lateral ventricles. Further, within people with 22qDS, there was a significant positive correlation between severity of (i) schizotypy score and grey matter volume of the temporo-occipital regions and the corpus striatum; (ii) emotional problems and grey matter volume of frontostriatal regions; and (iii) social behavioural difficulties and grey matter in frontostriatal regions. Thus, subjects with 22qDS have widespread changes in brain anatomy, particularly affecting white matter, basal ganglia and cerebellum. Also, within 22qDS, regionally specific differences in brain development may partially underpin behavioural differences. We suggest that there is preliminary evidence for specific vulnerability of the frontostriatal and cerebellar-cortical networks in 22qDS.

Cannabis use in early adolescence is associated with higher negative schizotypy in females.

The current study examined the relationship between early onset cannabis use (before age 16) and different schizotypy dimensions, and whether gender moderates these associations. Participants were 162 cannabis users, aged 15-24 years, who completed an online assessment examining alcohol and other drug use, psychological distress, and schizotypy. Participants were divided according to whether or not they had started using cannabis before the age of 16 (early onset=47; later onset=115) and gender (males=66; females=96). The interaction between gender and onset group was significantly associated with the dimension of introvertive anhedonia. Follow-up analyses showed that early onset cannabis use was associated with higher levels of introvertive anhedonia in females only. The current findings suggest that gender is an important moderator in the association between early onset cannabis use, schizotypy, and possibly, psychosis risk.