How does studying schizotypal personality disorder inform us about the prodrome of schizophrenia?

Neuropsychology and Neurobiology of Negative Schizotypy: A Selective Review

Schizotypy refers to a latent personality organization that reflects liability to schizophrenia. Because schizotypy is a multidimensional construct, people with schizotypy vary in behavioral and neurobiological features. In this article, we selectively review the neuropsychological and neurobiological profiles of people with schizotypy, with a focus on negative schizotypy. Empirical evidence is presented for alterations of neuropsychological performance in negative schizotypy. We also cover the Research Domain Criteria domains of positive valence, social process, and sensorimotor systems. Moreover, we systematically summarize the neurobiological correlates of negative schizotypy at the structural, resting-state, and task-based neural levels, as well as the neurochemical level. The convergence and inconsistency of the evidence are critically reviewed. Regarding theoretical and clinical implications, we argue that negative schizotypy represents a useful organizational framework for studying neuropsychology and neurobiology across different psychiatric disorders.

A preliminary study on the effectiveness of a stress management program for healthcare-related undergraduates with at-risk mental state

PURPOSE

This study aimed to examine the effects of a stress management program on stress perception and coping strategies for healthcare-related undergraduates with at-risk mental state (ARMS).

DESIGN AND METHODS

A randomized experimental design with pretest and posttest was used. Of the 2812 students screened, 65 were identified as having ARMS, 52 enrolled in the study, and 49 (75%) completed the study.

FINDINGS

Significance was found for subjects with schizotypal traits in emotion expression and problem-avoidance coping strategies. Subjects with trait anxiety improved significantly in interpersonal deficits after the program.

PRACTICE IMPLICATIONS

Students with different trait risks reported benefits in different stress-coping strategies from the program.

The effect of being left home alone at age 3 years on schizotypy and antisocial behavior at ages 17 and 23 years

OBJECTIVE

Negative home environments are associated with both schizophrenia-spectrum disorders and crime, but whether this is due to the social or cognitive sequelae of such environments is unclear. This study investigates the effect of early home environments on adult mental health.

METHOD

Using data from the Mauritius Child Health Project, a multiple time-point prospective study where all children born in 1969 in two towns (Quatre Bornes and Vacaos) were recruited at age 3 years (N = 1794), a group of children left home alone at age 3 (n = 34) were compared to children cared for by siblings/relatives (n = 222), or by mothers (n = 1498) on antisocial behavior and schizotypal personality at ages 11, 17, and 23 years.

RESULTS

Home alone children showed higher scores on psychotic behavior and conduct disorder at age 17, and also schizotypal personality and crime at 23 years compared to the other groups. No negative behavioral or cognitive effects were observed at age 11. Findings were not accounted for by social adversity or ethnicity and appear to be 'sleeper effects' in that they do not emerge until later adolescence and into adulthood.

CONCLUSIONS

Findings appear to be the first to show the negative effects of dual-parental daytime absence on adult schizotypy and crime, a finding that cannot be accounted for by verbal and spatial cognitive impairments. Results suggest an early common psychosocial denominator to the two comorbid conditions of antisocial behavior and schizotypy.

Childhood trauma and schizotypy: a systematic literature review

BACKGROUND

Schizotypy is a complex concept, commonly defined as a genetic vulnerability to schizophrenia that falls on a continuum between healthy variation and severe mental illness. There is a growing body of evidence supporting an association between childhood trauma and increased psychotic experiences and disorders. However, the evidence as to whether there is a similar association with schizotypy has yet to be systematically synthesized and assessed.

METHOD

We conducted a systematic search of published articles on the association between childhood trauma and schizotypy in four major databases. The search covered articles from 1806 to 1 March 2013 and resulted in 17,003 articles in total. Twenty-five original research studies met the eligibility criteria and were included in this review.

RESULTS

All 25 studies supported the association between at least one type of trauma and schizotypy, with odds ratios (ORs) ranging between 2.01 and 4.15. There was evidence supporting the association for all types of trauma, with no differential effects. However, there was some variability in the quality of the studies, with most using cross-sectional designs. Individuals who reported adverse experiences in childhood scored significantly higher on positive and negative/disorganized schizotypy compared to those who did not report such experiences.

CONCLUSIONS

All forms of childhood trauma and other stressful events (e.g. bullying) were found to be associated with schizotypy, with especially strong associations with positive schizotypy. However, because of the methodological limitations of several studies and a lack of further exploration of different possible mechanistic pathways underlying this association, more research is required.

Sensory gating disturbances in the spectrum: similarities and differences in schizotypal personality disorder and schizophrenia

BACKGROUND

DSM-5 places schizophrenia on a continuum from severe, chronic schizophrenia to the attenuated schizophrenia-like traits of schizotypal personality disorder (SPD), the prototypic schizophrenia-related personality disorder. SPD shares common genetic and neurobiological substrates with schizophrenia, including information processing abnormalities, although they are less marked. This is the first study to directly compare the P50 evoked electroencephalographic response-a measure of sensory gating and a neurophysiological endophenotype-between schizophrenia-spectrum groups. Two hypotheses were tested: (1) Compared with healthy controls (HCs), schizophrenia patients show reduced P50 suppression and SPD patients resemble schizophrenia but exhibit less marked deficits; and (2) Deficient P50 suppression in SPD is associated with greater clinical symptom severity.

METHODS

P50 was assessed in 32 schizophrenia-spectrum disorder patients (12 SPD, 20 schizophrenia patients) and 25 demographically-matched HCs. The standard conditioning (C)-testing (T) paradigm was used and P50 suppression was quantified using the T-C difference and the T/C ratio.

RESULTS

All P50 measures showed a linear, stepwise pattern with the SPD group intermediate between the HC and schizophrenia groups. Compared with HCs, both patient groups had lower conditioning and T-C difference values. Among the SPD group, greater clinical symptom severity was associated with greater conditioning-response amplitude deficits.

CONCLUSION

These findings: (1) are novel in showing that P50 deficits in SPD resemble those observed in schizophrenia, albeit less marked; (2) support the concept that the phenomenological link between SPD and schizophrenia lies in shared neurocognitive/neurophysiological pathologies; and (3) provide evidence that P50 is a neurophysiological endophenotype for schizophrenia-spectrum disorders.

The relationship between temperament and character and subclinical psychotic-like experiences in healthy adults

BACKGROUND

Considerable data support phenomenological and temporal continuity between psychotic disorders and subclinical psychotic-like experiences (PLE's). Although numerous studies have found similar personality correlates for schizophrenia and schizotypal personality disorder patients, their unaffected first-degree relatives, and healthy adults characterized for schizotypal traits, no study has yet investigated personality correlates of PLE's measured by the Community Assessment of Psychic Experiences (CAPE). Our study sought to examine personality correlates of PLE's using the CAPE in healthy adults.

METHOD

The CAPE and temperament and character inventory (TCI) were administered to 415 healthy adults. Regressions examined links between TCI traits and overall PLE levels as well as positive and negative PLE's separately.

RESULTS

Consistent with past studies, lower self-directedness (SD) and reward dependence (RD) and higher self-transcendence (ST) and harm avoidance (HA) significantly predicted overall PLE levels. Higher ST and persistence (P) and lower SD significantly predicted higher levels of positive PLE's while lower SD and RD and higher HA, ST, and cooperativeness (C) predicted higher levels of negative PLE's.

CONCLUSIONS

Associations between TCI and PLE's using the CAPE are strikingly similar to past work in non-clinical and patient samples and provide additional support for phenomenological continuity between psychotic disorders and sub-syndromal psychotic symptoms.

Schizotypy and personality profiles of Cluster A in a group of schizophrenic patients and their siblings

BACKGROUND

Schizotypy, or the set of personality traits related to schizophrenia, is considered an endophenotypic manifestation that is more represented in first-degree relatives of patients with schizophrenia than in the general population. The assessment of schizotypy is primarily based on self-reports, and for this reason it presents several limitations. In order to assess schizotypy, this study proposes a diagnostic instrument based on clinical reports.

METHODS

A sample of 66 subjects, composed of 25 outpatients with schizophrenia, 18 siblings of these patients and 23 healthy controls, was subjected to the personality assessment test SWAP-200 by trained clinical interviewers. To test the hypothesis of the difference between the profiles of the Personality Disorders within the schizophrenia spectrum, a Multivariate Analysis of Variance and subsequent planned comparisons were conducted.

RESULTS

Patients with schizophrenia scored higher than both their siblings and the controls on all SWAP-200 scales; their siblings, compared to the healthy controls, showed significant statistical differences, with higher mean scores for paranoid (F(1,63) = 7.02; p = 0.01), schizoid (F(1,63) = 6.56; p = 0.013) and schizotypal (F(1,63) = 6.47; p = 0.013) traits (PD T scores of Cluster A and Q-factor scores for the schizoid scale [F(1,63) = 6.47; p = 0.013]).

CONCLUSIONS

Consistent with previous data, first-degree relatives of patients with schizophrenia scored higher on schizophrenia-related personality traits than a general population comparison sample. SWAP-200, as an alternative diagnostic instrument to self-report measures, is able to reveal the higher prevalence of schizotypal traits in siblings of patients with schizophrenia, suggesting its possible use as a complementary instrument for the assessment of schizophrenia.

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.

'A rose is a rose is a rose', but at-risk criteria differ

BACKGROUND

Over the last 15 years, efforts to detect psychoses early in their prodromal states have greatly progressed; meanwhile, ultra-high risk (UHR) criteria have been the subject of such consensus that parts of them have been proposed for inclusion in DSM-5 in terms of an attenuated psychosis syndrome. However, it is frequently unacknowledged that the definitions and operationalizations of UHR-related at-risk criteria, including the relevant attenuated psychotic symptoms, vary considerably across centers and time and, thus, between prediction studies.

METHODS

These variations in UHR criteria are described and discussed with reference to the rates of transition to psychosis, their prevalence in the general population and the proposed new operationalization of the attenuated psychosis syndrome.

RESULTS

A comparison of samples recruited according to different UHR operationalizations reveals differences in the distribution of UHR criteria and transition rates as well as in the prevalence rates of at-risk criteria in the general population.

CONCLUSION

The evidence base for the introduction of such a new syndrome is weaker than the number of studies using supposedly equal UHR criteria would at first suggest. Thus, studies comparing the effects of different (sub-)criteria not only on transition rates and outcomes but also on other important aspects, such as neurocognitive performance and brain imaging results, are necessary. Meanwhile, the preliminary attenuated psychosis syndrome in DSM-5 should not follow an altogether new definition but, rather, the currently most reliable UHR definition, which must still demonstrate its reliability and validity outside specialized psychiatric services.

Prevalence, correlates, disability, and comorbidity of DSM-IV schizotypal personality disorder: results from the wave 2 national epidemiologic survey on alcohol and related conditions

OBJECTIVE

To present nationally representative findings on the prevalence, correlates, and comorbidity of and disability associated with DSM-IV schizotypal personality disorder (SPD).

METHOD

This study used the 2004-2005 Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions, which targeted a nationally representative sample of the adult civilian population of the United States aged 18 years and older and residing in households and group quarters. In Wave 2, attempts were made to conduct face-to-face reinterviews with all respondents to the Wave 1 interview.

RESULTS

Lifetime prevalence of SPD was 3.9%, with significantly greater rates among men (4.2%) than women (3.7%) (p < .01). Odds for SPD were significantly greater among black women, individuals with lower incomes, and those who were separated, divorced, or widowed; odds were significantly lower among Asian men (all p < .01). Schizotypal personality disorder was associated with substantial mental disability in both sexes. Co-occurrence rates of Axis I and other Axis II disorders among respondents with SPD were much higher than rates of co-occurrence of SPD among respondents with other disorders. After adjustment for sociodemographic characteristics and additional comorbidity, associations remained significant in both sexes between SPD and 12-month and lifetime bipolar I disorder, social and specific phobias, and posttraumatic stress disorder, as well as 12-month bipolar II disorder, lifetime generalized anxiety disorder, and borderline and narcissistic personality disorders (all p < .01).

CONCLUSIONS

Common and unique factors may underlie associations of SPD with narcissistic and borderline personality disorders, whereas much of the comorbidity between SPD and most mood and anxiety disorders appears to reflect factors common to these disorders. Some of the associations with SPD were sex specific. Schizotypal personality disorder and dependent, avoidant, and borderline personality disorders were associated with the occurrence of schizophrenia or psychotic episode. Schizotypal personality disorder is a prevalent, fairly stable, highly disabling disorder in the general population. Sex differences in associations of SPD with other specific Axis I and II disorders can inform more focused, hypothesis-driven investigations of factors underlying the comorbid relationships. Schizotypal as well as borderline, dependent, and avoidant personality disorders may be components of the schizophrenia spectrum.

Automatic sensory information processing abnormalities across the illness course of schizophrenia

BACKGROUND

Deficits in automatic sensory discrimination, as indexed by a reduction in the mismatch negativity (MMN) and P3a event-related potential amplitudes, are well documented in chronic schizophrenia. However, MMN and P3a have not been sufficiently studied early in the course of psychotic illness. The present study aimed to investigate MMN, P3a and reorienting negativity (RON) across the course of schizophrenia.

METHOD

MMN, P3a, and RON were assessed in 118 subjects across four groups: (1) individuals at risk for psychosis (n=26); (2) recent-onset patients (n=31); (3) chronic patients (n=33); and (4) normal controls (n=28) using a duration-deviant auditory oddball paradigm.

RESULTS

Frontocentral deficits in MMN and P3a were present in all patient groups. The at-risk group's MMN and P3a amplitudes were intermediate to those of the control and recent-onset groups. The recent-onset and chronic patients, but not the at-risk subjects, showed significant RON amplitude reductions, relative to the control group. Associations between MMN, P3a, RON and psychosocial functioning were present in the chronic patients. In the at-risk subjects, P3a and RON deficits were significantly associated with higher levels of negative symptoms.

CONCLUSIONS

Abnormalities in the automatic processes of sensory discrimination, orienting and reorienting of attention are evident in the early phases of schizophrenia and raise the possibility of progressive worsening across stages of the illness. The finding that MMN and P3a, but not RON, were reduced before psychosis onset supports the continued examination of these components as potential early biomarkers of schizophrenia.

Startle reactivity and prepulse inhibition in prodromal and early psychosis: effects of age, antipsychotics, tobacco and cannabis in a vulnerable population

The use of biomarkers in the study of the prodrome and first episode of psychosis provides a means of not only identifying individuals at greatest risk for psychosis but also understanding neurodevelopmental abnormalities early in the course of illness. Prepulse inhibition (PPI), a marker that is deficient in schizophrenia and after developmental manipulations in animal models, was assessed in 75 early psychosis (EP), 89 at risk (AR) for psychosis and 85 comparison subjects (CS) at baseline and 6 months. Consistent with findings in chronic schizophrenia, PPI was stable with repeated assessment and EP subjects had reduced PPI but this was most evident in tobacco smokers. A significant positive PPI and age association in AR and EP samples, but not CS, demonstrated potential neurodevelopmental differences in early psychosis. Unexpected findings included the fact that medication naive EP subjects, as well as AR subjects who later developed psychosis, had greater PPI, introducing the possibility of early compensatory changes that diverge from findings in chronic patients. In addition, subjects with a history of cannabis use had greater startle reactivity while EP and AR subjects who used cannabis and were also taking an antipsychotic had greater PPI, again highlighting the potentially important cannabis/psychosis association.

A multivariate perspective on schizotypy and familial association with schizophrenia: a review

Although generally accepted that schizotypal personality disorder diagnosis is more prevalent among relatives of individuals with schizophrenia and may be associated with genetic liability to schizophrenia, it seems likely that this diagnosis is itself heterogeneous and thus perhaps not as useful in identifying genes that affect schizophrenia risk (i.e. endophenotypes) as it could be. In contrast, symptoms and dimensions of schizotypal personality disorder may be more etiologically homogeneous, and thus more useful in genetic studies. The current review evaluated and consolidated evidence to date regarding specific symptoms and dimensions of schizotypal personality disorder among non-psychotic relatives of schizophrenia patients. Comparisons were made with relatives of affective disorder patients and non-psychiatric controls. Findings indicate strong support for elevation of social-interpersonal schizotypal symptoms among relatives of schizophrenia patients versus other groups along with moderate specificity. Results suggest only a small elevation of cognitive-perceptual and disorganized symptoms in relatives of schizophrenia patients and results for disorganized symptoms were inconsistent across studies. Thus, evidence to date supports further investigation of genetic associations between symptoms of schizotypal personality disorder and schizophrenia, and suggests that social-interpersonal symptoms may be particularly promising in genetic analyses of schizophrenia.

Reappraisal of the interplay between psychosis and depression symptoms in the pathogenesis of psychotic syndromes: results from a twenty-year prospective community study

The interplay of psychotic and affective symptoms is a crucial challenge in understanding the pathogenesis of psychosis. In this study, we analyzed the interplay between two subclinical psychosis symptoms dimensions, and one depression symptoms dimension, using longitudinal data from Zurich. The Zurich study started in 1979 with a representative sample of 591 participants who were aged 20/21. Follow-up interviews were conducted at age 23, 28, 30, 35, and 41. The psychiatric symptoms were assessed with a semi-structured interview and the SCL 90-R. In this study, we analyzed three SCL-90-R subscales: the depression symptoms dimension and two distinct symptoms dimensions of subclinical psychosis, one representing a schizophrenia nuclear symptom dimension, the other representing a schizotypal symptoms dimension. Modeling was done with hybrid latent growth models, thereby including simultaneous and cross-lagged effects. The interplay between the two subclinical psychosis symptoms dimensions and the depression symptoms dimension includes several intertwined pathways. The schizotypal symptoms dimension has strong direct effects on the schizophrenia nuclear symptoms dimension, but also on the depression symptoms dimension. The latter has for its part an effect on the schizophrenia nuclear symptoms dimension. The main driving force within the dynamic interplay between depression and psychosis symptoms is a schizotypal symptoms dimension, which represents social and interpersonal deficiencies, ideas of reference, suspiciousness, paranoid ideation, and odd behavior. It does not only directly influence subclinical nuclear schizophrenia symptoms but also the symptoms of depression.

Disorganized symptoms and executive functioning predict impaired social functioning in subjects at risk for psychosis

Predictors of social functioning deficits were assessed in 22 individuals "at risk" for psychosis. Disorganized symptoms and executive functioning predicted social functioning at follow-up. Early intervention efforts that focus on social and cognitive skills are indicated in this vulnerable population.

Sensitivity and specificity of the Chinese version of the Schizotypal Personality Questionnaire-Brief for identifying undergraduate students susceptible to psychosis

BACKGROUND

Early interventions can improve treatment outcomes for individuals with major psychiatric disorders and with nonspecific symptoms but increasingly impaired cognitive perception, emotions, and behaviour. One way used to identify people susceptible to psychosis is through the schizotypal personality trait. Persons with schizotypal characteristics have been identified with the widely used Schizotypal Personality Questionnaire-Brief. However, no suitable instruments are available to screen individuals in the Taiwanese population for evidence of early psychotic symptoms.

OBJECTIVES

The purpose of this study was to test the sensitivity and specificity of the Chinese version of the Schizotypal Personality Questionnaire-Brief for identifying undergraduate students' susceptibility to psychosis.

DESIGN

Two-stage, cross-sectional survey design.

SETTING AND PARTICIPANTS

The self-administered scale was tested in a convenience sample of 618 undergraduate students at a medical university in Taiwan. Among these students, 54 completed the scale 2 weeks apart for test-retest reliability, and 80 were tested to identify their susceptibility to psychosis.

DATA COLLECTION AND ANALYSIS

In Stage I, participants with scores in the top 6.5% were classified as the high-score group (n=40). The control group (n=40) was randomly selected from the remaining participants with scores <15 and matched by gender. These 80 students were asked to participate in psychiatric interviews in Stage II. The instrument was tested for reliability using intraclass correlation coefficients and the Kuder-Richardson formula 20. The instrument was analysed for optimal sensitivity and specificity using odds-ratio analysis and receiver operating characteristic curves.

RESULTS

The 22-item Chinese version of the Schizotypal Personality Questionnaire-Brief had a 2-week test-retest reliability of 0.82 and internal consistency of 0.76. The optimal cut-off score was 17, with odds ratios of 24.4 and an area under the receiver operating characteristic curves of 0.83. The instrument had a sensitivity of 80.0% and specificity of 85.9% in identifying undergraduate students' susceptibility to psychosis.

CONCLUSIONS

The Chinese version Schizotypal Personality Questionnaire-Brief is a reliable instrument, but should not be used as a screening tool until its psychometric properties have been evaluated in more detail. Other screening tools need to be used in future studies with the CSPQ-B to improve the accuracy of identifying susceptibility to psychosis among young adults.

Course of neurocognitive deficits in the prodrome and first episode of schizophrenia

Understanding the trajectory of cognitive changes in the development of schizophrenia may shed light on the neurodevelopmental processes in the beginning stage of illness. Subjects at risk for psychosis (AR, n = 48), patients in their first episode of schizophrenia (FE, n = 20), and normal comparison subjects (n = 29) were assessed on a neurocognitive battery at baseline and at a 6-month follow-up. There were significant group differences across all cognitive domains as well as a significant group by time interaction in the verbal learning domain. After statistically controlling for practice effects and regression to the mean, a high proportion of FE subjects showed an improvement in verbal learning, and a significant number of AR subjects improved in general intelligence. Moreover, a higher than expected percentage of FE subjects, as well as AR subjects who later converted to psychosis, showed a deterioration in working memory and processing speed. These inconsistent trajectories suggest that some domains may improve with stabilization in the early stages of psychosis, whereas others may decline with progression of the illness, indicating possible targets for cognitive remediation strategies and candidate vulnerability markers for future psychosis.

Validity of the prodromal risk syndrome for first psychosis: findings from the North American Prodrome Longitudinal Study

Treatment and prevention studies over the past decade have enrolled patients believed to be at risk for future psychosis. These patients were considered at risk for psychosis by virtue of meeting research criteria derived from retrospective accounts of the psychosis prodrome. This study evaluated the diagnostic validity of the prospective "prodromal risk syndrome" construct. Patients assessed by the Structured Interview for Prodromal Syndromes as meeting criteria of prodromal syndromes (n = 377) from the North American Prodrome Longitudinal Study were compared with normal comparison (NC, n = 196), help-seeking comparison (HSC, n = 198), familial high-risk (FHR, n = 40), and schizotypal personality disorder (SPD, n = 49) groups. Comparisons were made on variables from cross-sectional demographic, symptom, functional, comorbid diagnostic, and family history domains of assessment as well as on follow-up outcome. Prodromal risk syndrome patients as a group were robustly distinguished from NC subjects across all domains and distinguished from HSC subjects and from FHR subjects on most measures in many of these domains. Adolescent and young adult SPD patients, while distinct from prodromal patients on definitional grounds, were similar to prodromals on multiple measures, consistent with SPD in young patients possibly being an independent risk syndrome for psychosis. The strong evidence of diagnostic validity for the prodromal risk syndrome for first psychosis raises the question of its evaluation for inclusion in Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition).

Schizophrenia, "just the facts" 4. Clinical features and conceptualization

Although dementia praecox or schizophrenia has been considered a unique disease entity for the past century, its definitions and boundaries have continued to vary over this period. At any given time, the changing concept of schizophrenia has been influenced by available diagnostic tools and treatments, related conditions from which it most needs to be distinguished, extant knowledge and scientific paradigms. There is significant heterogeneity in the etiopathology, symptomatology, and course of schizophrenia. It is characterized by an admixture of positive, negative, cognitive, mood, and motor symptoms whose severity varies across patients and through the course of the illness. Positive symptoms usually first begin in adolescence or early adulthood, but are often preceded by varying degrees of negative and cognitive symptomatology. Schizophrenia tends to be a chronic and relapsing disorder with generally incomplete remissions, variable degrees of functional impairment and social disability, frequent comorbid substance abuse, and decreased longevity. Although schizophrenia may not represent a single disease with a unitary etiology or pathogenetic process, alternative approaches have thus far been unsuccessful in better defining this syndrome or its component entities. The symptomatologic, course, and etio-pathological heterogeneity can usefully be addressed by a dimensional approach to psychopathology, a clinical staging approach to illness course, and by elucidating endophenotypes and markers of illness progression, respectively. This will allow an approach to the deconstruction of schizophrenia into its multiple component parts and strategies to reconfigure these components in a more meaningful manner. Possible implications for DSM-V and ICD-11 definitions of schizophrenia are discussed.

Predictors of remission, schizophrenia, and bipolar disorder in adolescents with brief psychotic disorder or psychotic disorder not otherwise specified considered at very high risk for schizophrenia

OBJECTIVE

The aim of this study was to examine predictors of diagnostic and symptomatic outcome in adolescents with either psychotic disorder not otherwise specified (PsyNOS) or brief psychotic disorder (BrPsy) followed in a schizophrenia prodromal program.

METHODS

As part of a naturalistic study of adolescents considered at clinical high risk for schizophrenia, 26 youths (mean age, 15.9 +/- 2.6 years, 65.4% male) with psychosis not fulfilling criteria for schizophrenia/schizoaffective disorder and diagnosed with PsyNOS or BrPsy were evaluated for predictors of diagnostic and symptomatic outcome after at least 6 (mean, 22.8 +/- 19.4) months follow up.

RESULTS

Progression to schizophrenia, schizoaffective disorder, or psychotic bipolar disorder (n = 10, 38.5%) was predicted by fulfilling criteria for schizotypal personality disorder at baseline (p = 0.046). Development of schizophrenia/schizoaffective disorder (n = 7, 27.0%) was associated with worse executive functioning (p = 0.029) and absence of anxiety disorders (p = 0.027). Conversely, progression to bipolar disorder (n = 4, 15.4%), with (n = 3, 11.5%) or without (n = 1, 3.8%) psychosis, was associated with the presence of anxiety disorders (p = 0.014). Remission of all psychotic as well as attenuated positive or negative symptoms (n = 5, 19.4%) was predicted by Hispanic ethnicity (p = 0.0047), an initial diagnosis of BrPsy (p = 0.014), longer duration of antidepressant treatment (p = 0.035), and better attention at baseline (p = 0.042).

CONCLUSIONS

Results from this preliminary study suggest that patients with PsyNOS, BrPsy, or schizotypal personality disorder features in adolescence should be followed as separate risk groups in prodromal studies of schizophrenia and bipolar disorder. Executive function deficits and absence of anxiety disorders may be risk markers for schizophrenia, while presence of anxiety disorders may be linked to bipolar disorder risk. After achieving full remission, patients with sudden onset of psychosis and brief episodes could once be given the option of careful, supervised treatment discontinuation. The potential salutary effect of antidepressants during the psychotic prodrome and presence of characteristics differentiating patients at risk for schizophrenia or bipolar disorder should be investigated further.

Obstetrical complications in people at risk for developing schizophrenia

Many factors have been associated with the development of schizophrenia, yet few studies have looked at these same factors in individuals considered at risk for schizophrenia, but who have not yet reached diagnostic threshold. The rate of obstetrical complications was assessed as part of a comprehensive battery in subjects at risk (N=52), or in the first episode of schizophrenia (N=18), and in normal comparison subjects (N=43). The rate of obstetrical complications was increased in the at risk (46%) and first episode (39%) samples compared to the normal comparison (19%) group, however, follow-up analyses were only significant between the at risk and normal comparison subjects. Obstetrical complications may be an important risk factor in identifying vulnerable subjects and ultimately may, along with other risk factors, be part of an algorithm for determining likelihood of developing schizophrenia.

Neurocognitive deficits in the (putative) prodrome and first episode of psychosis

OBJECTIVE

International research programs have contributed to the creation of operationally defined criteria to identify individuals at risk for schizophrenia. Although there has been substantial progress in the prospective study of the schizophrenia prodrome, the utility of current diagnostic criteria remains questionable because of the relatively low base rates of incident psychoses, the high false-positive rate and ethical concerns regarding the treatment of individuals at risk. The identification of brain based neurocognitive vulnerability markers for schizophrenia may contribute to the development of an at risk algorithm with greater predictive accuracy.

METHODS

Forty subjects at risk (AR) for schizophrenia, 15 in their first episode (FE) of schizophrenia, and 36 healthy comparison (HC) subjects were administered a neurocognitive battery that assessed the domains of processing speed, working memory, verbal episodic memory, executive functioning and general intelligence.

RESULTS

At baseline, AR subjects showed neurocognitive deficits across all domains compared to HC subjects that were less severe than those observed in the FE sample. In preliminary analyses, AR subjects who later converted to psychosis (N=5) had greater neurocognitive impairment at baseline evaluation compared to those individuals who remained "at risk" at follow-up.

CONCLUSIONS

Neurocognitive deficits may be important in the pathogenesis of early psychosis and could help to define individuals at greatest risk for schizophrenia. Continued research in larger cohorts is needed to test the validity of this neurocognitive profile and its utility as a vulnerability marker.

Social functioning in young people at risk for schizophrenia

Deficits in social functioning are potential risk factors for schizophrenia. Social functioning was assessed in 55 individuals "at risk" for schizophrenia, 16 first episode patients with schizophrenia and 45 normal comparison subjects. The Social Adjustment Inventory for Children and Adolescents (SAICA) was administered to adolescents <18 and the Social Adjustment Scale (SAS-SR) to young adults >17. The at risk and first episode groups significantly differed from the normal subjects on measures of social functioning in the domains of peer, family, work and school relationships. Individuals at risk for schizophrenia have significant functional deficits which may be potential indicators of increased vulnerability for psychosis.

Cannabis abuse and risk for psychosis in a prodromal sample

The goal of the present study was to examine the rate of cannabis use among participants in the Cognitive Assessment and Risk Evaluation (CARE) Program, a longitudinal program for individuals who are "at risk" for developing a psychotic disorder. Cannabis abuse was assessed in 48 individuals identified as at risk for psychosis based on subsyndromal psychotic symptoms and/or family history. At 1 year follow-up, 6 of the 48 (12.5%) at risk subjects had made the transition to psychosis. Of the 32 subjects who had no use or minimal cannabis use, one subject (3.1%) converted to psychosis. Of the 16 subjects who met criteria for cannabis abuse/dependence, five (31.3%) converted to psychosis. The results show a significant association between cannabis abuse and conversion to psychosis in this sample. Nicotine use was also found to be significantly associated with later conversion. The significant associations between cannabis and nicotine abuse and conversion to psychosis in individuals at risk for schizophrenia suggest that early identification and intervention programs should screen for and provide education about the deleterious effects of these substances.

Insight and frontal cortical function in schizophrenia: a review

Insight into illness has been identified as a clinically important phenomenon, in no small part due to an association with treatment-adherence. An increasing number of studies, but not all, have observed poor insight to be a reflection of cognitive dysfunction in schizophrenia. A review of 34 published English-language studies found a significant number (i.e., 21) reporting a relationship between insight deficits and impaired performance on cognitive tasks primarily mediated by frontal cortex. A significant number of reviewed studies examined insight function in more than one psychiatric population, including bipolar and schizoaffective disorder. The most replicated findings from these studies were the correlations between insight deficits and impaired performance on the Wisconsin Card Sorting Test (WCST). More specifically, WCST perseverative errors correlated positively and the number of categories completed correlated negatively with poor insight, suggesting that impaired insight may be mediated by deficiencies in conceptual organization and flexibility in abstract thinking. Since the WCST requires the ability to demonstrate conceptual flexibility through the generation, maintenance and switching of mental sets along with the capacity to use verbal feedback to correct errors, it would appear that such 'executive' functions are most related to insight. In addition, recently identified structural correlates of poor insight in schizophrenia show some association with anosognosia in neurological patients. This review will discuss the implications of these findings and directions for future research.

Generalized and specific cognitive performance in clinical high-risk cohorts: a review highlighting potential vulnerability markers for psychosis

Cognitive deficits are a core feature of established psychotic illnesses. However, the association between cognition and emerging psychosis is less understood. While there is some evidence that cognitive deficits are present prior to the onset of psychosis, findings are not consistent. In this article we provide an overview of the more general cognitive findings available from genetic high-risk studies, retrospective studies, and birth cohort studies. We then focus the review on neuropsychological performance in clinically "at-risk" groups. Overall, general cognitive ability as assessed by established batteries appears to remain relatively intact in these ultra-high risk cohorts and is a poor predictor close to illness onset relative to other vulnerability factors. Further decline may occur with illness progression, more consistent with state relative to trait factors. In addition, most established cognitive tasks involve several relatively discrete cognitive subprocesses, where findings from general batteries of subtests may mask specific deficits. In this context, our review suggests that relatively specific olfactory identification and spatial working memory deficits exist prior to illness onset and may be more potent trait markers for psychosis than cognitively dense tasks such as verbal memory. Suggestions for further research address the importance of standardization of inclusion criteria and the maintenance of basic neuropsychological assessment to allow better comparison of findings across centers. Further, in order to better understand the aetiopathology of cognitive dysfunction in psychosis, more experimental, hypothesis-driven measures of discrete cognitive processes are required. Delineation of the relationship between specific cognitive ability and symptoms from data-driven approaches may improve our understanding of the role of cognition during psychosis onset.

Prospective investigations of the prodromal state of schizophrenia: review of studies

OBJECTIVE

The paper presents a comprehensive overview of prospective studies monitoring or intervening in the pre-onset phase of first episode psychosis.

METHOD

A systematic literature search was conducted and supplemented by a manual search. All relevant studies were ordered and intensively reviewed according to specified criteria. Methodological and conceptual issues are discussed.

RESULTS

Reports of 23 prospective studies were found, some describing subsamples of larger samples. Major methodological and conceptual divergences exist.

CONCLUSION

Applied criteria detect individuals with a significantly increased risk of psychosis within the schizophrenia spectrum, but these criteria are only validated on clinical populations. The significance of differences in sample-characteristics is unclear. Most study samples are small. Results are preliminary and in need of further research before they constitute a realistic knowledge base. Methodological and conceptual issues should not be underestimated.

Risk and protection in prodromal schizophrenia: ethical implications for clinical practice and future research

Over the last decade schizophrenia researchers have turned their attention to earlier identification in the prodromal period of illness. A greater understanding of both risk and protective factors can lead to improved prevention and treatment strategies in this vulnerable population. This research, however, has far-reaching ethical implications. One year follow-up data from 50 individuals who met established criteria for a prodromal state is used to illustrate ethical issues that directly affect clinicians and future research strategies. At 1-year follow-up, the psychotic transition rate was 13%, but it increased in subsequent years with smaller sample sizes. One-half developed an affective psychosis. The converted sample was older (p > 0.05) than the nonconverted sample and more likely to have a premorbid history of substance abuse, as well as higher clinical ratings on "subsyndromal" psychotic items (delusional thinking, suspiciousness, and thought disorder). Despite a lack of conversion, the nonconverted sample remained symptomatic and had a high rate of affective and anxiety disorders with evidence of functional disability. This conversion rate is relatively low compared to similar studies at 1 year. Specific risk factors were identified, but these findings need to be replicated in a larger cohort. By examining the rate of conversion and nonconversion in this sample as an example, we hope to contribute to the discussion of implications for clinical practice and the direction of future research in the schizophrenia prodrome. Finally, our data strengthen the evidence base available to inform the discussion of ethical issues relevant to this important research area.

Schizotypal personality disorder or prodromal symptoms of schizophrenia?

Schizotypal personality disorder shares some attenuated phenotypic features with schizophrenia, but represents an independent syndrome. In contrast, prodromal symptoms of schizophrenia represent early warning signs of the impending onset of schizophrenia. Although these constructs are intended to reflect independent syndromes, self-report instruments measuring these constructs assess similar symptoms. It does not appear that existing research has examined the relative discriminant validity of screening instruments for these syndromes. A sample of 998 young adults (68% female; 73% Caucasian), within the age of risk for schizophrenia (ages 18-34; mean 20.4+/-2.2), met validity criteria after completing online versions of the Abbreviated Schizotypal Personality Questionnaire (SPQ-B) and the 24-item Abbreviated Youth Psychosis at Risk Questionnaire (Y-PARQ-B). Based on clinical cut-off scores used in previous research, 5.2% were [only] considered at heightened risk for psychosis (potentially prodromal), 3.4% had [only] schizotypal personality features, and 2.9% met criteria for both constructs (75% of individuals meeting cutoff for one measure did not meet criteria for the other). Males and younger participants scored significantly higher on both measures. The total scores from the SPQ-B and Y-PARQ-B showed a significant positive correlation (r(s)=.66, p<.001, R2=.43); however, 57% of the variance was not shared between the measures. Of the three SPQ-B subscales, Cognitive-Perceptual showed the strongest correlation with Y-PARQ-B. Results suggest that the SPQ-B and Y-PARQ-B have moderate discriminate validity between the overlapping, yet distinct, constructs of schizotypal personality and heightened risk of developing psychosis (potentially prodromal).

Progress in the Prospective Study of the Schizophrenia Prodrome

Further understanding of the schizophrenia spectrum has helped to define the prodrome of the illness, leading to hopes of earlier identification and intervention in susceptible, at-risk individuals. Given the heterogeneity and comorbidity observed in the clinically and demographically identified prodromal sample, it is essential that neurobiological markers that are more closely linked to brain function, and perhaps the ability to predict evolution of psychosis, be identified. Ultimately, it may be possible to identify an algorithm of risk factors that will combine clinical and demographic risk factors with vulnerability markers associated with later development of schizophrenia to better target at-risk individuals or preventative treatment.