Precursors to schizophrenia: do biological markers have specificity?

Prodromal features in first-psychotic episodes of major affective and schizoaffective disorders

BACKGROUND

Study aims were to analyze psychopathological details of prodromes leading to first-lifetime psychotic episodes and apply them to improve prediction of final diagnoses.

METHODS

Comprehensive records of subjects with final diagnoses of bipolar I (BD-I; n = 216), schizoaffective (SzAffD; n = 71), or psychotic major-depressive (MDD; n = 42) disorders in the Harvard-McLean First-Psychotic Episode Project were analyzed to identify psychopathological details of prodromes leading to first-lifetime episodes with psychotic features and their ability to predict final diagnoses tested with multivariable logistic regression modeling.

RESULTS

While held blind to final diagnoses, we identified 84 distinct psychopathological characteristics of prodromes to first-psychotic episodes, including perceptual disturbances, affective symptoms, sleep disturbances, onset rate, and duration. Prevalence of 19 factors appeared to differ among final diagnoses, and were tested with multivariable regression modeling. Significantly and independently more associated with final diagnoses of MDD than BD-I were 7 features: suicidal ideation, somatic delusions, anorexia, lack of insomnia, older presenting age, depressive symptoms, and lack of impulsivity; 9 others were associated more with later SzAffD than MDD or BD-I: lack of insomnia, homicidal behavior, lack of excitement, visual hallucinations, command hallucinations, longer prodrome, male sex, responding to internal stimuli, and younger age at presentation.

LIMITATIONS

Historical-retrospective and prospective assessments may have misidentified some prodromal features, and subjects with final psychotic-MDD diagnosis were relatively few.

CONCLUSIONS

Psychopathological features identified during prodromes leading to first-episodes with psychotic features predicted and distinguished among final diagnoses of MDD, BD-I, and SzAffD. The findings add to growing impressions that early psychopathology has value in predicting final diagnoses of major affective and schizoaffective disorders.

Cross-diagnostic evaluation of minor physical anomalies in psychiatric disorders

BACKGROUND

Minor physical anomalies (MPA) are markers of impaired neurodevelopment during the prenatal stage. Assessing MPA across psychiatric disorders may help understand their shared nature. In addition, MPA in family members would indicate a shared liability and endophenotype potential. We examined familial aggregation of MPA and their role as transdiagnostic and disorder-specific markers of 5 major psychiatric/neuropsychiatric conditions (schizophrenia, bipolar disorder, substance dependence, obsessive-compulsive disorder, and Alzheimer's dementia).

METHODS

Modified Waldrop's MPA scale was applied on 1321 individuals from 439 transdiagnostic multiplex families and 125 healthy population controls (HC). Stage of fetal development (morphogenetic/phenogenetic)- and anatomical location (craniofacial/peripheral)-based sub-scores were calculated. Familiality and endophenotypic potential of MPA were analyzed with serial negative binomial mixed-effect regression. Cross-diagnostic differences and the effect of family history density (FHD) of each diagnosis on MPA were assessed. Mixed-effects Cox models estimated the influence of MPA on age-at-onset of illness (AAO).

RESULTS

MPA were found to be heritable in families with psychiatric disorders, with a familiality of 0.52. MPA were higher in psychotic disorders after controlling for effects of sex and intrafamilial correlation. Morphogenetic variant MPA was noted to be lower in dementia in comparison to HC. FHD of schizophrenia and bipolar disorder predicted higher, and that of dementia and substance dependence predicted lower MPA. MPA brought forward the AAO [HR:1.07 (1.03-1.11)], and this was more apparent in psychotic disorders.

CONCLUSION

MPA are transmissible in families, are specifically related to the risk of developing psychoses, and predict an earlier age at onset. Neurodevelopmentally informed classification of MPA has the potential to enhance the etiopathogenic and translational understanding of psychiatric disorders.

Environmental influences in schizophrenia: the known and the unknown

Despite much research, environmental influences that can be said to cause a schizophrenic illness remain elusive. When the effects of an (often prolonged) prodromal syndrome are taken into account, the first episode appears to come from nowhere. However, over the past couple of decades a number of factors have emerged that can be argued to influence, and not merely reflect, the illness onset. The possible effects of season and geography of birth, urbanisation, immigration, substance misuse, prenatal influenza, famine and other stresses, and obstetric complications are summarised. These varied findings, often of small effect and borderline significance, present a challenge to clinicians attempting to make sense of their patients' life experiences. Any hard conclusions still depend largely on how one formulates the illness.

Improving risk assessment and familial aggregation of age at onset in schizophrenia using minor physical anomalies and craniofacial measures

Age at onset is the most important feature of schizophrenia that could indicate its origin. Minor physical anomalies (MPAs) characterize potential marker indices of disturbances in early neurodevelopment. However, the association between MPAs and age at onset of schizophrenia is still unclear. We aimed to compare risk assessment and familial aggregation in patients with early-onset schizophrenia (EOS) and adult-onset schizophrenia (AOS) with MPAs and craniofacial measures.We estimated the risk assessment of MPAs among patients with EOS (n = 68), patients with AOS (n = 183), nonpsychotic relatives (n = 147), and healthy controls (n = 241) using 3 data-mining algorithms. In addition, we assessed the magnitude of familial aggregation of MPAs with respect to the age at onset of schizophrenia.The performance of EOS was superior to that of AOS, with discrimination accuracies of 89% and 76%, respectively. Combined MPA scores as the risk assessment were significantly higher in all schizophrenia subgroups and the nonpsychotic relatives of EOS patients than in the healthy controls. The recurrence risk ratio for familial aggregation of the MPA scores of EOS families (odds ratio 9.27) was substantially higher than that of AOS families (odds ratio 2.47).The results highlight that EOS improves risk assessment and has a severe magnitude of familial aggregation of MPAs. These findings indicate that EOS might result from a stronger genetic susceptibility to neurodevelopmental deficits.

Biological and psychosocial risk factors for psychotic major depression

AIMS

Few studies have investigated risk factors for psychotic major depression (PMD). We aimed to investigate the biological and psychosocial risk factors associated with PMD compared with other psychotic disorders.

METHODS

Based on the aetiology and ethnicity in schizophrenia and other psychoses (ÆSOP) study, we used a case-control study to identify and recruit, at baseline and 10-year follow-up, all first episode cases of psychosis, presenting for the first time to specialist mental health services in defined catchment areas in the UK. Population-based controls were recruited from the same areas. Data were collected on: sociodemographics; social isolation; childhood adversity; life events; minor physical anomalies; and neurological soft signs.

RESULTS

Living alone (aOR = 2.26, CI = 1.21-4.23), basic level qualification (aOR = 2.89, CI = 1.08-7.74), being unemployed (aOR = 2.12, CI = 1.13-3.96), having contact with friends less than monthly (aOR = 4.24, CI = 1.62-11.14), having no close confidants (aOR = 4.71, CI = 2.08-10.68), having experienced childhood adversity (aOR = 2.57, CI = 1.02-6.44), family history of mental illness (aOR = 10.68, CI = 5.06-22.52), family history of psychosis (aOR = 12.85, CI = 5.24-31.51), and having more neurological soft signs (aOR = 1.15, CI = 1.07-1.24) were all associated with a follow-up diagnosis of PMD and schizophrenia. Few variables associated with PMD were also associated with a diagnosis of bipolar disorder. Minor physical anomalies were associated with a follow-up diagnosis of schizophrenia and bipolar disorder, but not PMD.

CONCLUSIONS

Risk factors associated with PMD appear to overlap with those for schizophrenia, but less so for bipolar disorder. Future work on the differential aetiology of PMD, from other psychoses is needed to find the 'specifier' between PMD and other psychoses. Future research on aetiology in PMD, and perhaps other psychoses, should account for diagnostic change.

Minor physical anomalies and craniofacial measures in patients with treatment-resistant schizophrenia

BACKGROUND

Schizophrenia patients have higher rates of minor physical anomalies (MPAs) than controls, particularly in the craniofacial region; this difference lends support to the neurodevelopmental model of schizophrenia. Whether MPAs are associated with treatment response in schizophrenia remains unknown. The aim of this case-control study was to investigate whether more MPAs and specific quantitative craniofacial features in patients with schizophrenia are associated with operationally defined treatment resistance.

METHOD

A comprehensive scale, consisting of both qualitatively measured MPAs and quantitative measurements of the head and face, was applied in 108 patients with treatment-resistant schizophrenia (TRS) and in 104 non-TRS patients. Treatment resistance was determined according to the criteria proposed by Conley & Kelly (2001; Biological Psychiatry 50, 898-911).

RESULTS

Our results revealed that patients with TRS had higher MPA scores in the mouth region than non-TRS patients, and the two groups also differed in four quantitative measurements (facial width, lower facial height, facial height, and length of the philtrum), after controlling for multiple comparisons using the false discovery rate. Among these dysmorphological measurements, three MPA item types (mouth MPA score, facial width, and lower facial height) and earlier disease onset were further demonstrated to have good discriminant validity in distinguishing TRS from non-TRS patients in a multivariable logistic regression analysis, with an area under the curve of 0.84 and a generalized R 2 of 0.32.

CONCLUSIONS

These findings suggest that certain MPAs and craniofacial features may serve as useful markers for identifying TRS at early stages of the illness.

Study of minor physical anomalies in complete nuclear Mexican families. Evidence of neurodevelopmental problems in schizophrenia

Introduction

Minor physical anomalies (MPA) are dysmorphic features that reflect deviations in early development, are morphological variants that appear during the first trimester of pregnancy and could be used as a marker of disease risk in susceptible people. The literature agrees that the number of MPA is higher in patients with schizophrenia compared with their relatives and healthy subjects. The purpose of this study is to compare the MPA, assessed using the Gourion Scale, in complete nuclear families (families with a member with schizophrenia and control families) by determining the MPA mean, concordance and heritability for the total score on the MPA Gourion Scale for each anomaly.

Method

The sample consisted of 60 families with at least one schizophrenic patient (284 members) and 61 control families (249 members). Results: The mean total score for the scale was 5.72 ± 2.3 MPA in the case of families with at least one schizophrenic patient and 1.8 ± 4.46 MPA for control families. The average for families of patients without considering the patient in the analysis was 5.59 ± 2.3 MPA; for patients, the mean was 6.14 ± 2.4 MPA. In the analysis by anomaly differences were found only in eleven anomalies found no evidence of heritability or concordance.

Conclusions

MPA occur more frequently in patients, but a pattern of low consistency between them persists. It is concluded that MPA could be a marker of neurodevelopmental problems, but it is not suitable to consider them a Gourion scale as endophenotype.

Evaluation of spontaneous dense array gamma oscillatory activity and minor physical anomalies as a composite neurodevelopmental endophenotype in schizophrenia

OBJECTIVE

Minor physical anomalies (MPAs) and gamma oscillatory activity have been proposed as associated endophenotypes in schizophrenia. Combining these endophenotypes to create a composite endophenotype may help identify those at risk for schizophrenia better. The present study aims to investigate MPAs and gamma oscillatory activity in schizophrenia patients, their unaffected first degree relatives and healthy controls and appreciate whether they can be used together as a composite endophenotype.

METHODS

This was a cross sectional family study conducted at a tertiary care mental health setup. Ninety participants including schizophrenia patients, their first degree relatives and controls (thirty each) were assessed for MPAs on the Extended Waldrop Scale. All participants underwent an awake, resting 192-channel EEG recording. Spectral power and coherence in 30-100Hz gamma bands were estimated using Welch's averaged periodogram method. One-way ANOVA, chi square test were used for comparing socio-demographic-clinical variables. MANOVA supplemented by one-way ANOVAs (post hoc Tukey HSD) were done for comparison of spectral measures. Pearson's correlation, step-by-step linear discriminant functional and intra-familial correlation analysis were subsequently performed.

RESULTS

An endophenotype pattern of finding was found for MPAs in the craniofacial region, the total number of MPAs, spectral power in right temporal region on all bands and in the right parietal region in 50-70Hz and 70-100Hz gamma bands. The three groups were most accurately classified when MPA total score, right temporal 30-50Hz gamma power and right occipital 'intra hemispheric' 50-70Hz gamma coherence were considered together than when considered independently. Significant intra familial correlation was seen for MPA total score and right temporal gamma 30-50Hz power.

CONCLUSION

Composite evaluation of two developmentally linked markers i.e. MPAs and gamma spectral measures may prove useful in categorizing schizophrenia and identifying at-risk individuals.

Cognitive deficits in youth with familial and clinical high risk to psychosis: a systematic review and meta-analysis

OBJECTIVE

It is likely that cognitive deficits are vulnerability markers for developing schizophrenia, as these deficits are already well-established findings in first-episode psychosis. Studies at-risk adolescents and young adults are likely to provide information about cognitive deficits that predate the onset of the illness.

METHOD

We conducted meta-analyses of studies comparing familial-high risk (FHR) or ultra-high risk (UHR; n = 2113) and healthy controls (n = 1748) in youth studies in which the mean age was between 15 and 29.

RESULTS

Compared with controls, high risk subjects were impaired in each domain in both UHR (d = 0.34-0.71) and FHR (d = 0.24-0.81). Heterogeneity of effect sizes across studies was modest, increasing confidence to the findings of the current meta-analysis (I(2) = 0-0.18%). In both risk paradigms, co-occurrence of genetic risk with attenuated symptoms was associated with more severe cognitive dysfunction. In UHR, later transition to psychosis was associated with more severe cognitive deficits in all domains (d = 0.31-0.49) except sustained attention. However, cognitive impairment has a limited capacity to predict the outcome of high-risk patients.

CONCLUSION

Cognitive deficits are already evident in adolescents and young adults who have familial or clinical risk for psychosis. Longitudinal developmental studies are important to reveal timing and trajectory of emergence of such deficits.

Using natural disasters to study the effects of prenatal maternal stress on child health and development

Research on the developmental origins of health and disease highlights the plasticity of the human fetus to a host of potential teratogens. Experimental research on laboratory animals has demonstrated a variety of physical and behavioral effects among offspring exposed to prenatal maternal stress (PNMS). However, these studies cannot elucidate the relative effects of the objective stress exposure and the subjective distress in a way that would parallel the stress experience in humans. PNMS research with humans is also limited because there are ethical challenges to designing studies that involve the random assignment of pregnant women to varying levels of independent stressors. Natural disasters present opportunities for natural experiments of the effects of pregnant women's exposure to stress on child development. In this review, we present an overview of the human and animal research on PNMS, and highlight the results of Project Ice Storm which has been following the cognitive, behavioral, motor and physical development of children exposed in utero to the January 1998 Quebec Ice Storm. We have found that both objective degree of exposure to the storm and the mothers' subjective distress have strong and persistent effects on child development, and that these effects are often moderated by the timing of the ice storm in pregnancy and by the child's sex.

Antecedents of manic versus other first psychotic episodes in 263 bipolar I disorder patients

OBJECTIVE

As initial episode type can predict later morbidity in bipolar disorder, we tested the hypothesis that clinical antecedents might predict initial episode types.

METHOD

We studied 263 first-episode, adult, DSM-IV-TR type I bipolar disorder (BD-I) subjects within the McLean-Harvard-International First-Episode Project. Based on blinded assessments of antecedents from SCID examinations and clinical records, we compared first lifetime manic vs. other (mixed, depressive, or non-affective) major psychotic episodes.

RESULTS

We identified 32 antecedents arising at early, intermediate or later times, starting 12.3±10.7 years prior to first lifetime major psychotic episodes. Based on multivariate modeling, antecedents associated significantly and independently with other (n=113) more than manic (n=150) first lifetime major psychotic episodes ranked by odds ratio: more early attentional disturbances, more late depression, more early perplexity, more detoxification, more early unstable mixed affects, more antidepressants, more early dysphoria, more intermediate depression, more early impulsivity, more late anhedonia, longer early-to-intermediate intervals, more intermediate substance abuse, more family history of major depression, and younger at earliest antecedents. Antecedents selectively preceding manic more than other first psychotic episodes included more late behavioral problems and more risk of familial BD-I.

CONCLUSION

Clinical antecedents in adult, BD-I patients, beginning a decade before first major episodes and progressing through sequential stages were dissimilar in manic vs. other first psychotic episodes.

Somatosensory timing deficits in schizophrenia

Schizophrenia is often accompanied by disturbances in motor behavior thought to result from abnormalities in the brain's timing mechanisms. Virtually all behavior has a motor component, and proper regulation of motor behavior is often dependent upon accurate registration of somatosensory input. This study uses the steady-state evoked response (SSR) to quantify the accuracy of timing of the neocortical response to rapidly presented tactile somatosensory stimuli in patients with schizophrenia compared to control subjects. We used magnetic evoked fields and source space projection to estimate the time course of equivalent current sources in somatosensory cortex. Wavelet-based time-frequency analysis was used to compute intertrial timing consistency and amplitudes. SSRs in schizophrenic subjects demonstrated decreased performance in both metrics to contralateral 25-Hz tactile stimulation. Previous studies have reported similar abnormalities in the SSR in both auditory and visual domains. The magnetic SSR to tactile stimuli is thought to reflect activation of layer 3 pyramidal cells in primary sensory cortex. Thus, these findings, as in other sensory domains, are suggestive of impaired GABAergic inhibitory interneuronal control of the timing of pyramidal cell activity. This deficit may be intrinsic to neocortex, or might reflect as well impairment of cerebellar and/or thalamic involvement. These findings reinforce the notion that abnormalities in the brain's timing mechanisms are a central component of the schizophrenia syndrome.

Childhood determinants of adult psychiatric disorder

The aim of this project was to assess the current evidence from longitudinal studies for childhood determinants of adult mental illness. Because of the variable and often prolonged period between factors in childhood and the identification of mental illness in adults, prospective studies, particularly birth cohorts, offer the best chance of demonstrating associations in individuals.

A review was undertaken in 2006 of the published literature from longitudinal studies, together with some large-scale retrospective studies and relevant reviews which provided supplementary evidence. The main focus was upon potentially ameliorable characteristics, experiences or situations of childhood; however, other factors, not determinants but pre-cursors, associated with later mental illness could not be left out.

Seven major electronic data-bases of published research were interrogated with a range of key-words and the results supplemented from personal searches, enquiries and reference trails. In excess of 1,500 abstracts were read to select 250 papers for full review. The material was assessed in relation to ten factors:

Psychological disturbance; Genetic Influences; Neurological Deviance; Neuroticism; Behaviour; School Performance; Adversity; Child Abuse or Neglect; Parenting and parent-child relationships; Disrupted and Disfunctional Families.

In 2011 the search was repeated for the period 2006 to mid-2011, using the same search terms and supplemented in the same manner. Over 1,800 abstracts emerged and almost 200 papers selected for more detailed review. These were then integrated into the original text with modifications where necessary. The whole text was then revised and edited in January / February 2012.

There is continuing evidence for the association with later mental ill-health for each of these ten factors, but with different degrees of conviction. The evidence for each is discussed in detail and weighed both separately and in relation to others. These are then summarised, and the research implications are considered. Finally, the implications for prevention are discussed together with the practical potential for preventive and health-promoting programmes.

Minor physical anomalies in patients with schizophrenia in a Chinese population

Studies have shown that minor physical anomalies (MPAs) may be associated with schizophrenia. However, it remains unclear whether any items of MPAs are more associated with schizophrenia than the others. We aimed to examine which specific MPAs are more associated with schizophrenia than others. A total of 154 patients with schizophrenia and 152 healthy controls were assessed using candidate MPAs items along with items from the Waldrop scale. Significant differences were found between the patients and controls in inner canthal distance, epicanthus, adherent ear lobe, cuspidal ear and length difference from section index to ring finger (2D:4D length difference) as well as gap between the first and the second toes. These six items were selected by the logistic regression model, which correctly classified 89.0% of patients with schizophrenia (sensitivity) and 96.7% of healthy controls (specificity). The overall classification success rate was 92.8%. MPAs are associated with neurodevelopment, especially 2D:4D associated with cerebral lateralisation. Hence, our present findings support that it is necessary to evaluate MPAs beyond the Waldrop scale, as some item, such as 2D:4D length difference may reflect the more detailed aberrant neurodevelopment of schizophrenia.

Case Study: A Structural Model for Schizophrenia and Family Collaboration

This single case study describes a structural therapy perspective applied to a family and examines interaction patterns within the clinical setting and the home; the therapeutic view examines contextual variables that affect an individual diagnosed with schizophrenia, his family, and his recovery. The therapeutic experience of one client diagnosed with schizophrenia and his family is presented. The client’s symptoms were tracked using a pre- and posttest from the Sixteen Personality Factor Questionnaire (16 PF) assessment tool over the 15-week treatment period. There was a significant change from pretest to posttest for the following factors: warmth, emotional stability, dominance, liveliness, rule consciousness, vigilance, openness to change, self-reliance, self-control, and tension.

The psychosis risk syndrome and its proposed inclusion in the DSM-V: a risk-benefit analysis

The inclusion of a psychosis risk syndrome has been proposed for the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders. The appropriateness of inclusion of this new risk syndrome in the DSM depends on a careful analysis of both anticipated benefits and risks. Purported benefits include early recognition and case identification, and the hypothetical benefit of preventive intervention of psychotic disorders, for which there is as yet no clear evidence base. However, there is a potential for high rates of false positives particularly at the community level given the difficulty in discriminating mild symptoms from normal variants and low base rates of the syndrome in the general population. High false-positive rates in and of themselves are not necessarily problematic if the risk-benefit ratio is significantly favorable, as with screening for cardiovascular risk factors. For the psychosis risk syndrome, by contrast, there are substantial risks, for both stigma and discrimination, and for unnecessary exposure to antipsychotic medications, which make the high false-positive rate associated with the psychosis risk designation particularly problematic. More research is needed to improve the positive predictive value of the psychosis risk syndrome so that it can be considered for inclusion in future editions of the DSM.

Significance of morphological features in schizophrenia of a Chinese population

Neuro-developmental hypothesis suggests that schizophrenia is originated from aberrant brain development during first and/or early trimester of gestation. Accordingly, when a schizophrenia gene is involved in the regulation of embryonic development and continues to play a role in the later life, it may result in the co-occurrence of defective organ systems and/or physiological functions with schizophrenia. We proposed a checklist with 13 morphological features and examine their prevalence rates in 151 schizophrenic patients and 151 controls. Statistical analyses showed that single transverse palmar crease, head circumference, covered epicanthus, finger length difference, and inner canthus distance, made significant contributions to schizophrenia. To rule out the age confounding effects on morphological features, we dropped older schizophrenic subjects and younger controls in further regression analysis. The regression model correctly classified 82.8% of control subjects (specificity) and 86.4% of schizophrenic patients (sensitivity), and provided an overall successful classification rate of 84.5%, with single transverse palmar crease on the first rank. The association of morphological features and schizophrenia is probably genetic in origin, as specific morphological features were more frequent in non-affected parents with higher genetic loading of schizophrenia. In addition, the association of finger length difference in schizophrenia found in this study has never been reported elsewhere. Our study showed that five out of 13 morphological features in the propose checklist may be used as biomarkers for schizophrenia, either for clinical practice or research purposes.

Childhood onset diagnoses in a case series of teens at clinical high risk for psychosis

REASONS: Schizophrenia is typically an adult neurodevelopmental disorder that has its antecedents in childhood and adolescence. Little is known about disorders "usually first diagnosed in infancy, childhood and adolescence" (e.g., childhood-onset disorders) in "prodromal" teens at heightened clinical risk for psychotic disorder.

MAIN FINDINGS

Childhood-onset disorders were prevalent in putatively prodromal teens, including anxiety and disruptive disorders, attention-deficit/hyperactivity disorder (ADHD), and, surprisingly, elimination disorders. These may reflect developmental antecedents in psychotic disorders such as schizophrenia.

KEY DATA AND STATISTICS

A case series of 9 teens (ages 13-17) identified as prodromal to psychosis were evaluated with the Kiddie Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL). Childhood-onset diagnoses commonly endorsed (threshold or subthreshold) included ADHD (5/9), oppositional defiant disorder (5/9), enuresis or encopresis (4/9), conduct disorder (2/9), separation anxiety (3/9), and transient tic disorder (2/9). Enuresis was identified in 3 of the 4 older teens (ages 15-17).

MAJOR CONCLUSIONS

An understanding of the childhood-onset disorders that occur in teens at risk for psychotic illnesses, such as schizophrenia, can shed light on the pathophysiology of schizophrenia and potentially inform early identification and intervention.

The antecedents of schizophrenia: a review of birth cohort studies

BACKGROUND

Birth cohort (BC) studies demonstrate that individuals who develop schizophrenia differ from the general population on a range of developmental indices. The aims of this article were to summarize key findings from BC studies in order to identify areas of convergence and to outline areas requiring further research.

METHOD

We define BC studies as studies based on general population BCs where data are collected prospectively from birth or childhood and which identify schizophrenia or related disorders as an outcome. To identify such studies, we searched various electronic databases using the search parameters (schizo* OR psych*) AND (birth cohort). We also checked the references of relevant articles and previous reviews.

RESULTS

We identified 11 BCs from 7 countries that have examined schizophrenia as an outcome in adulthood. There is relatively consistent evidence that, as a group, children who later develop schizophrenia have behavioral disturbances and psychopathology, intellectual and language deficits, and early motor delays. Evidence with respect to alterations in language, educational performance, and physical growth has also been identified in some studies. BC studies have also contributed evidence about a wide range of putative risk factors for schizophrenia.

CONCLUSIONS

BC studies have provided important, convergent insights into how the developmental trajectory of individuals who develop schizophrenia differs from their peers. The combination of new paradigms and larger cohorts, with the tools of modern epidemiology and biomedical science, is advancing our understanding of the developmental pathways to schizophrenia.

Absence of established sex differences in patients with schizophrenia on a two-dimensional object array task

Sex differences are pervasive in schizophrenia, ranging from differences in the age of onset and symptoms of the illness to structural brain differences. Yet, there has been very little research on the interaction of these differences with established cognitive sex differences that exist in healthy populations. We tested 25 patients with schizophrenia and 17 healthy controls on a two-dimensional task of object location memory. It has been previously shown that healthy females outperform healthy males on this task, a result that was upheld in this experiment. However, the female advantage is completely absent in patients with schizophrenia. This finding has important implications for the interpretation of clinical and physiological sex differences present in schizophrenia.

Prenatal maternal stress from a natural disaster predicts dermatoglyphic asymmetry in humans

Dermatoglyphic asymmetry of fingertip ridge counts is more frequent in schizophrenia patients than normal controls, and may reflect disruptions in fetal development during Weeks 14–22 when fingerprints develop. However, there are no data in humans linking specific adverse events at specific times to dermatoglyphic asymmetries. Our objective was to determine whether prenatal exposure to a natural disaster (1998 Quebec ice storm) during Weeks 14–22 would result in increased dermatoglyphic asymmetry in children, and to determine the roles of maternal objective stress exposure, subjective stress reaction, and postdisaster cortisol. Ridge counts for homologous fingers were scored for 77 children (20 target exposed [Weeks 14–22] and 57 nontarget exposed [exposed during other gestation weeks]). Children in the target group had more than 0.50 SD greater asymmetry than the nontarget group. Within the target group, children whose mothers had high subjective ice storm stress had significantly greater asymmetry than those with lower stress mothers, and maternal postdisaster cortisol had a significant negative correlation with the children's dermatoglyphic asymmetry (r = −.56). Prenatal maternal stress during the period of fingerprint development results in greater dermatoglyphic asymmetry in their children, especially in the face of greater maternal distress.

Minor physical anomalies in affective disorders. A review of the literature

BACKGROUND

The increased frequency of MPAs may be external markers of abnormal brain development in affective disorders.

METHODS

A MEDLINE, psychInfo and Web of Science search was evaluated to collect all publications on the prevalence of minor physical anomalies in bipolar affective disorder and unipolar major depression.

AIMS

As reports on the prevalence of MPAs in affective disorders were controversial, were based on highly different number of patients and were evaluated by the use of scales with different sensitivities, we considered as important to review the current state of knowledge and to recommend directions to further research.

RESULTS

14 publications on 12 studies were found after a careful literature search. 5 studies have dealt with the prevalence of MPAs in bipolar affective disorder, 3 have reported on examinations among patients with unipolar major depression, while 5 publications on 3 studies combined patients with bipolar affective disorder, schizoaffective disorder and unipolar major depression. 1 study was published on the prevalence of MPAs among mood disorders, without the differentiation of the data of patients with bipolar affective disorder and unipolar major depression.

LIMITATIONS

Few studies with relatively small size were published, there is no data on the distinction between bipolar I and bipolar II disorders.

CONCLUSION

The reviewed data suggest a higher probability of the role of an aberrant neurodevelopment in bipolar affective disorder and a smaller in unipolar major depression.

Minor physical anomalies in patients with first-episode psychosis: their frequency and diagnostic specificity

BACKGROUND

An increased prevalence of minor physical anomalies (MPAs) has been extensively documented in schizophrenia but their specificity for the disorder remains unclear. We investigated the prevalence and the predictive power of MPAs in a large sample of first-episode psychotic patients across a range of diagnoses.

METHOD

MPAs were examined in 242 subjects with first-episode psychosis (50% schizophrenia, 45% affective psychosis and 5% substance-induced psychosis) and 158 healthy controls. Categorical principal components analysis and analysis of variance were undertaken, and individual items with the highest loading were tested using the chi2 test.

RESULTS

Overall facial asymmetry, assymetry of the orbital landmarks, and frankfurt horizontal significantly differentiated patients with schizophrenia and affective psychosis from controls, as did a 'V-shaped' palate, reduced palatal ridges, abnormality of the left ear surface and the shape of the left and right ears. Patients with affective psychosis had significantly lowered eye fissures compared with control subjects.

CONCLUSIONS

MPAs are not specific to schizophrenia, suggesting a common developmental pathway for non-affective and affective psychoses. The topographical distribution of MPAs in this study is suggestive of an insult occurring during organogenesis in the first trimester of pregnancy.

Epidemiology of schizophrenia: review of findings and myths

By describing patterns of disease distribution within populations, identifying risk factors, and finding associations, epidemiologic studies have contributed to the current understanding of schizophrenia. Advanced paternal age and the association with autoimmune diseases are some of the newly described epidemiologic findings shaping the current definition of schizophrenia. Although early intervention strategies have gained momentum, primary prevention of schizophrenia still seems a very distant aspiration. This article reviews the major epidemiological features of schizophrenia, with particular attention to the recent advances using population-based data. It also discusses some pervasive misconceptions about schizophrenia epidemiology, such as universal distribution and gender equality.

Minor physical anomalies in schizophrenia: a meta-analysis

Numerous studies report an increased frequency of minor physical anomalies (MPAs) in schizophrenic individuals compared with controls. However, these studies vary considerably regarding the magnitude of the case-control disparity and the topographical distribution of the anomalies. A meta-analysis was carried out on the existing MPA literature in an effort to better understand the relationship between MPAs and schizophrenia. Following a literature search, 13 studies were identified that met our inclusion criteria. Mean total MPA scores were available for 11 of these studies, whereas only seven studies provided regional MPA scores. For both the total MPA and regional MPA analyses, pooled effect sizes (Hedges' g and pooled odds ratios, respectively) were calculated along with tests of heterogeneity. For the total MPA analyses, a meta-regression approach was used to explore the relationship between possible moderator variables (e.g., number of MPA scale items) and effect size heterogeneity. The magnitude of the pooled effect size for the total MPA scores was high (1.131; p<0.001), indicating significantly more overall MPAs in schizophrenic individuals. Significant effect size heterogeneity was present (p<0.001); however, this heterogeneity could not be explained by any of the included moderator variables. The regional MPA analysis revealed significantly increased MPAs in all six anatomical regions (p<0.05), although the pooled odds ratios for these regions did not differ significantly from one another. These results suggest a lack of regional specificity for MPAs in schizophrenia.

Neuropsychological performance over time in people at high risk of developing schizophrenia and controls

BACKGROUND

Neuropsychological assessments of relatives of schizophrenics have shown subtle impairments in verbal memory, executive and intellectual function, which are stable in those beyond the age of maximum risk for the disorder. We sought to: (1) determine baseline neurocognitive predictors of psychosis, and (2) compare performance over time between relatives within the age of maximum risk, and controls.

METHODS

(1) and (2) were examined in 118 individuals at familial high risk of schizophrenia (HR) and 30 controls (C), using one-way analyses of variance (ANOVAs) and repeated measures analyses of covariance (ANCOVAs), controlling for intelligence quotient, time between and number of assessments, and correcting for multiple comparisons.

RESULTS

HR who became ill (n = 13) performed nonsignificantly less well at baseline than HR who did not (n = 105) on a test of verbal learning (t(109) = 2.1, p = .03). Across assessments, C performed significantly better than the entire HR group on immediate (F(3,133) = 5.11, p = .002) and delayed (F(3,133) = 5.02, p = .002) story recall. There were no significant interactions of time by group.

CONCLUSIONS

Results suggest greater verbal memory impairment in HR who go on to develop schizophrenia. Stable differences between groups over time suggest a trait deficit, which is relatively unaffected by the presence of psychotic symptoms and psychosis onset. Alternatively, small numbers may have precluded detection of group by time interactions.

Season of birth is associated with anthropometric and neurocognitive outcomes during infancy and childhood in a general population birth cohort

The 'season of birth' effect is one of the most consistently replicated associations in schizophrenia epidemiology. In contrast, the association between season of birth and development in the general population is relatively poorly understood. The aim of this study was to explore the impact of season of birth on various anthropometric and neurocognitive variables from birth to age seven in a large, community-based birth cohort. A sample of white singleton infants born after 37 weeks gestation (n = 22,123) was drawn from the US Collaborative Perinatal Project. Anthropometric variables (weight, head circumference, length/height) and various measures of neurocognitive development, were assessed at birth, 8 months, 4 and 7 years of age. Compared to summer/autumn born infants, winter/spring born infants were significantly longer at birth, and at age seven were significantly heavier, taller and had larger head circumference. Winter/spring born infants were achieving significantly higher scores on the Bayley Motor Score at 8 months, the Graham-Ernhart Block Test at age 4, the Wechsler Intelligence Performance and Full Scale scores at age 7, but had significantly lower scores on the Bender-Gestalt Test at age 7 years. Winter/spring birth, while associated with an increased risk of schizophrenia, is generally associated with superior outcomes with respect to physical and cognitive development.

Predicting schizophrenia: findings from the Edinburgh High-Risk Study

BACKGROUND

The hypothesis that schizophrenia is neurodevelopmental was investigated in a prospective study of young people with a postulated 10-15% risk for the development of schizophrenia.

AIMS

To determine premorbid variables distinguishing high-risk people who will go on to develop schizophrenia from those who will not.

METHOD

A high-risk sample of 163 young adults with two relatives with schizophrenia was recruited. They and 36 controls were serially examined. Baseline measures were compared between those who did develop schizophrenia, a well control group, a well high-risk group and high-risk participants with partial or isolated psychotic symptoms.

RESULTS

Of those at high risk, 20 developed schizophrenia within 2(1/2) years. More experienced isolated or partial psychotic symptoms. Those who developed schizophrenia differed from those who did not on social anxiety, withdrawal and other schizotypal features. The whole high-risk sample differed from the control group on developmental and neuropsychological variables.

CONCLUSIONS

The genetic component of schizophrenia affects many more individuals than will develop the illness, and partial impairment can be found in them. Highly significant predictors of the development of schizophrenia are detectable years before onset.

Risk factors and the prevalence of neurosis and psychosis in ethnic groups in Great Britain

BACKGROUND

Our aim was to examine whether variations in the prevalence of neurosis and psychosis between ethnic minorities throughout Great Britain are explained by social disadvantage.

METHOD

A total of 10,108 adult householders throughout Great Britain were assessed in a two-stage survey with the Revised Clinical Interview Schedule (CIS-R) and Psychosis Screening Questionnaire (PSQ). Respondents with a positive PSQ or who received a diagnosis of, or treatment for, psychosis were examined by a psychiatrist using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). Data on respondents' preferred ethnic group were collapsed into four groups: Whites, African-Caribbean or Africans, south Asians and other.

RESULTS

Ethnic grouping was strongly associated with: unemployment; lone parent status; lower social class; low perceived social support; poverty (indicated by lack of car ownership) and having a primary social support group of less than three close others. All these associations applied to the group Africans and Afro-Caribbeans, but only some applied to the other groups. No ethnic group had significantly increased rates of neurosis. Only the African-Caribbean group were at significantly increased risk of a psychotic disorder (odds ratio 4.55; 95% CI: 1.13, 18.30). After adjustment for risk factors, the odds of psychosis were lower (odds ratio 2.97; 95% CI: 0.66, 13.36).

CONCLUSIONS

The excess of psychosis in Africans and Afro-Caribbeans in Great Britain appears to be partly explained by socio-economic disadvantage, but larger studies are needed to confirm this.

Health and development in the first 4 years of life in offspring of women with schizophrenia and affective psychoses: Well-Baby Clinic information

The investigation of genetic high-risk (HR) groups provides the opportunity to study diathesis characteristics associated with schizophrenia (Sc) and affective psychoses. High-risk offspring of women with a history of schizophrenia, affective and other psychoses (n = 84), as well as normal-risk control (NC) offspring (n = 100), were studied from 0 to 4 years of age, using prospectively recorded information from Well-Baby Clinic (WBC) records. Blind assessment of an average of 25 contacts per subject yielded data concerning early life developmental, physical and behavioral characteristics associated with psychosis risk. As compared with controls, offspring of women with schizophrenia showed significantly increased rates of delayed walking, visual dysfunction, language skill disorders, enuresis, disturbed behavior (especially poor social competence), and multiple accumulated risk characteristics. Significant Sc-risk characteristics did not include impaired hearing, minor malformations, biological dysfunctions, or physical illness leading to treatment. Offspring of mothers with affective psychosis (Aff) showed only a significantly increased rate of delayed walking, with no significantly increased total aggregation of risk characteristics, compared with controls. The results suggest a limited overlap in the diathesis characteristics associated with risk for Sc vs. Aff psychosis. The importance of these early risk characteristics for the later development of psychopathology is being investigated in this sample.

Minor physical anomalies in schizophrenia: is age a confounding factor?

Minor physical anomalies (MPAs) occur more frequently in a range of developmental disorders. They are also more frequent in schizophrenia supporting a neurodevelopmental aetiology of the illness. Contemporary MPA scales are yet to be validated for the effects of age. It is hypothesised that the effects of ageing may be confounding when these scales are applied to an elderly population. The distribution of MPAs in a normal elderly population was compared with younger subjects. Fifty subjects over the age of 60, and 50 subjects below the age of 60, with no known major mental illness, were evaluated. MPAs were assessed using a modified Lane scale [Psychol. Med. 27 (1997) 1155]. Elderly subjects showed an excess of absent trichions due to alopecia (p=0.004) short and broad palates (p=0.01) and greater ear protrusion (p=0.004) relative to young subjects. The differences reported are probably due to hair loss, edentulousness and growth of the auriculocephalic angle with age. These findings question the validity of studies of MPAs in schizophrenia that do not control for age.

A qualitative research study of the evolution of symptoms in individuals identified as prodromal to psychosis

Because schizophrenia is difficult to treat and exacts large personal and societal costs, there is an effort underway to identify adolescents and young adults at high risk for psychosis. Theory-derived criteria of subthreshold positive symptoms identify a "prodromal" or clinically at-risk population who have conversion rates to psychosis of 40 to 50% within one to two years. However, further characterization of the psychosis prodrome by qualitative research methods could increase the predictive value of the "prodromal" designation. We conducted open-ended interviews with 20 parents of prodromal adolescents that focused on changes observed. The narratives fell into two thematically distinct subgroups, identified as "declining" and "never normal." The prodromal adolescents described as "declining" had a higher subsequent rate of conversion to psychosis than did the "never normal" group. Although preliminary, these results suggest that a trajectory of change in personality, relationships, and behavior from an essentially normal baseline may be consistent with increased risk for psychosis among prodromal adolescents.

Specificity of developmental precursors to schizophrenia and affective disorders

Developmental precursors to adult disorder suggest that components of their causes operate in early life. Several birth cohort studies have relevant prospective data and are reporting results for schizophrenia and affective disorder. These studies suggest that developmental findings are not specific for schizophrenia, although the magnitude of effects tends to be greater compared with affective disorder. These findings are reviewed and some methodological issues discussed. Apparent lack of specificity may mask underlying unique mechanisms and causes. In terms of a future public health perspective involving prediction and prevention, a lack of specificity may be advantageous.