Hallucinations are a major aspect of psychosis and a diagnostic feature of both psychotic and mood disorders. However, the field lacks information regarding the long-term course of hallucinations in these disorders. Our goals were to determine the percentage of patients with hallucinations and the relationship between hallucinations and recovery, and work attainment.

The present study was a prospective evaluation of the 20-year trajectory of hallucinations in 150 young patients: 51 schizophrenia, 25 schizoaffective, 25 bipolar with psychosis, and 49 unipolar depression. The patients were studied at an index phase of hospitalization for hallucinations, and then reassessed longitudinally at six subsequent follow-ups over 20 years.

The longitudinal course of hallucinations clearly differentiated between schizophrenia and bipolar disorder with psychosis, and suggested some diagnostic similarities between schizophrenia and schizoaffective disorder, and between bipolar disorder and schizoaffective disorder and depression. Frequent or persistent hallucinatory activity over the 20-year period was a feature of 40–45% of schizophrenia patients. The early presence of hallucinations predicted the lack of future periods of recovery in all patients. Increased hallucinatory activity was associated with reduced work attainment in all patients.

This study provides data on the prospective longitudinal course of hallucinations, which were previously unavailable to the field, and are one of the key features of psychosis in major psychiatric disorders. This information on the clinical course of major psychiatric disorders can inform accurate classification and diagnosis.

Knowledge of the risk of recurrence after recovery from major depressive disorder (MDD) in the general population is scarce.

Data were derived from 687 subjects in the general population with a lifetime DSM-III-R diagnosis of MDD but without a current major depressive episode (MDE) or dysthymia. Participants had to be at least 6 months in remission, and were recruited from The Netherlands Mental Health Survey and Incidence Study (NEMESIS), using the Composite International Diagnostic Interview (CIDI). Recency and severity of the last MDE were assessed retrospectively at baseline. Recurrence of MDD was measured prospectively during the 3-year follow-up. Kaplan–Meier survival curves were used to measure time to recurrence. Determinants of time to recurrence were analyzed using proportional hazard models.

The estimated cumulative recurrence of MDD was 13.2% at 5 years, 23.2% at 10 years and 42.0% at 20 years. In bivariate analysis, the following variables predicted a shorter time to recurrence: younger age, younger age of onset, higher number of previous episodes, a severe last depressive episode, negative youth experiences, ongoing difficulties before recurrence and high neuroticism. Multivariably, younger age, a higher number of previous episodes, a severe last depressive episode, negative youth experiences and ongoing difficulties remained significant.

In this community sample, the long-term risk of recurrence was high, but lower than that found in clinical samples. Subjects who had had an MDE had a long-term vulnerability for recurrence. Factors predicting recurrence included illness- and stress-related factors.

Previous studies support Beck's cognitive model of vulnerability to depression. However, the relationship between his cognitive triad and other clinical features and risk factors among those with major depression (MD) has rarely been systematically studied.

The three key cognitive symptoms of worthlessness, hopelessness and helplessness were assessed during their lifetime worst episode in 1970 Han Chinese women with recurrent MD. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression.

Compared to patients who did not endorse the cognitive trio, those who did had a greater number of DSM-IV A criteria, more individual depressive symptoms, an earlier age at onset, a greater number of episodes, and were more likely to meet diagnostic criteria for melancholia, postnatal depression, dysthymia and anxiety disorders. Hopelessness was highly related to all the suicidal symptomatology, with ORs ranging from 5.92 to 6.51. Neuroticism, stressful life events (SLEs) and a protective parental rearing style were associated with these cognitive symptoms.

During the worst episode of MD in Han Chinese women, the endorsement of the cognitive trio was associated with a worse course of depression and an increased risk of suicide. Individuals with high levels of neuroticism, many SLEs and high parental protectiveness were at increased risk for these cognitive depressive symptoms. As in Western populations, symptoms of the cognitive trio appear to play a central role in the psychopathology of MD in Chinese women.

Childhood emotional maltreatment (CEM) has been associated with disturbances in emotional and behavioral functioning, and with changes in regional brain morphology. However, whether CEM has any effect on the intrinsic organization of the brain is not known. In this study, we investigated the effects of CEM on resting-state functional connectivity (RSFC) using seeds in the limbic network, the default-mode network (DMN) and the salience network, and the left dorsomedial prefrontal cortex (dmPFC).

Using 3-T magnetic resonance imaging (MRI), resting-state functional MRI (RS-fMRI) scans were obtained. We defined seeds in the bilateral amygdala, the dorsal anterior cingulate cortex (dACC), the posterior cingulate cortex (PCC) and the left dmPFC, and used these to examine whether individuals reporting CEM (n=44) differed from individuals reporting no CEM (n=44) in RSFC with other brain regions. The two groups were matched for age, gender, handedness and the presence of psychopathology.

CEM was associated with decreased RSFC between the right amygdala and the bilateral precuneus and a cluster extending from the left insula to the hippocampus and putamen. In addition, CEM was associated with decreased RSFC between the dACC and the precuneus and also frontal regions of the brain.

We found that CEM has a profound effect on RSFC in the limbic network and the salience network. Regions that show aberrant connectivity are related to episodic memory encoding, retrieval and self-processing operations.

Although many studies have addressed the topic of stability versus change in depressive symptoms, few have further decomposed the change to continuous accumulation versus non-systematic state fluctuations or measurement errors. This further step requires a longitudinal follow-up and an appropriate stochastic model; it would, for example, evaluate the hypothesis that women accumulate more susceptibility events than men.

A linear stochastic differential equation model was estimated for a 16-year longitudinal course of depressive symptoms in the Young Finns community sample of 3596 participants (1832 women, 1764 men). This model enabled us to decompose the variance in depression symptoms into a stable trait, cumulative effects and state/error fluctuations.

Women showed higher mean levels and higher variance of depressive symptoms than men. In men, the stable trait accounted for the majority [61%, 90% confidence interval (CI) 48.9–69.2] of the total variance, followed by cumulative effects (23%, 90% CI 9.9–41.7) and state/error fluctuations (16%, 90% CI 5.6–23.2). In women, the cumulative sources were more important than among men and accounted for 44% (90% CI 23.6–58.9) of the variance, followed by stable individual differences (32%, 90% CI 18.5–54.2) and state fluctuations (24%, 90% CI 19.1–27.3).

The results are consistent with previous observations that women suffer more depression than men, and have more variance in depressive symptoms. We also found that continuously accumulating effects are a significant contributor to between-individual differences in depression, especially for women. Although the accumulating effects are often confounded with non-systematic state fluctuations, the latter are unlikely to exceed 27% of the total variance of depressive symptoms.

Evidence shows that cognitive deficits and white matter (WM) dysconnectivity can independently be associated with clinical manifestations in schizophrenia. It is important to explore this triadic relationship in order to investigate whether the triplet could serve as potential extended endophenotypes of schizophrenia.

Diffusion tensor images and clinical performances were evaluated in 122 individuals with first-episode schizophrenia and 122 age- and gender-matched controls. In addition, 65 of 122 of the patient group and 40 of 122 controls were measured using intelligence quotient (IQ) testing.

The schizophrenia group showed lower fractional anisotropy (FA) values than controls in the right cerebral frontal lobar sub-gyral (RFSG) WM. The schizophrenia group also showed a significant positive correlation between FA in the RFSG and performance IQ (PIQ); in turn, their PIQ score showed a significant negative correlation with negative syndromes.

Overall, these findings support the hypothesis that WM deficits may be a core deficit that contributes to cognitive deficits as well as to negative symptoms.

Stress and cortisol administration are known to have impairing effects on memory retrieval in healthy humans. These effects are reported to be altered in patients with major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) but they have not yet been investigated in borderline personality disorder (BPD).

In a placebo-controlled cross-over study, 71 women with BPD and 40 healthy controls received either placebo or 10 mg of hydrocortisone orally before undertaking a declarative memory retrieval task (word list learning) and an autobiographical memory test (AMT). A working memory test was also applied.

Overall, opposing effects of cortisol on memory were observed when comparing patients with controls. In controls, cortisol had impairing effects on memory retrieval whereas in BPD patients cortisol had enhancing effects on memory retrieval of words, autobiographical memory and working memory. These effects were most pronounced for specificity of autobiographical memory retrieval. Patients with BPD alone and those with co-morbid PTSD showed this effect. We also found that co-morbid MDD influenced the cortisol effects: in this subgroup (BPD + MDD) the effects of cortisol on memory were absent.

The present results demonstrate beneficial effects of acute cortisol elevations on hippocampal-mediated memory processes in BPD. The absence of these effects in patients with co-morbid MDD suggests that these patients differ from other BPD patients in terms of their sensitivity to glucocorticoids (GCs).

Cognitive ability/intelligence quotient (IQ) in youth has previously been associated with subsequent completed and attempted suicide, but little is known about the mechanisms underlying the associations. This study aims to assess the roles of various risk factors over the life course in explaining the observed relationships.

The present investigation is a cohort study based on data on IQ test performance and covariates, recorded on 49 321 Swedish men conscripted in 1969–1970, at ages 18–20 years. Information on suicides and hospital admissions for suicide attempt up to the age of 57 years, childhood and adult socio-economic position, and adult family formation, was obtained from linkage to national registers.

Lower IQ was associated with increased risks of both suicide and suicide attempt during the 36 years of follow-up. The associations followed a dose–response pattern. They were attenuated by approximately 45% in models controlling for social background, mental ill-health, aspects of personality and behavior, adult socio-economic position and family formation. Based on one-unit decreases in IQ test performance on a nine-point scale, the hazard ratios between ages 35 and 57 years were: for suicide 1.19 [95% confidence interval (CI) 1.13–1.25], fully adjusted 1.10 (95% CI 1.04–1.18); and for suicide attempt 1.25 (95% CI 1.20–1.31), fully adjusted 1.14 (95% CI 1.09–1.20).

Cognitive ability was found to be associated with subsequent completed and attempted suicide. The associations were attenuated by 45% after controlling for risk factors measured over the life course. Psychiatric diagnosis, maladjustment and aspects of personality in young adulthood, and social circumstances in later adulthood, contributed in attenuating the associations.

Cognitive remediation (CR) is an effective treatment for several psychiatric disorders. To date, there have been no published studies examining solely first-episode psychiatric cohorts, despite the merits demonstrated by early intervention CR studies. The current study aimed to assess the effectiveness of CR in patients with a first-episode of either major depression or psychosis.

Fifty-five patients (mean age = 22.8 years, s.d. = 4.3) were randomly assigned to either CR (n = 28) or treatment as usual (TAU; n = 27). CR involved once-weekly 2-h sessions for a total of 10 weeks. Patients were comprehensively assessed before and after treatment. Thirty-six patients completed the study, and analyses were conducted using an intent-to-treat (ITT) approach with all available data.

In comparison to TAU, CR was associated with improved immediate learning and memory controlling for diagnosis and baseline differences. Similarly, CR patients demonstrated greater improvements than TAU patients in psychosocial functioning irrespective of diagnosis. Delayed learning and memory improvements mediated the effect of treatment on psychosocial functioning at a marginal level.

CR improves memory and psychosocial outcome in first-episode psychiatric out-patients for both depression and psychosis. Memory potentially mediated the functional gains observed. Future studies need to build on the current findings in larger samples using blinded allocation and should incorporate longitudinal follow-up and assessment of potential moderators (e.g. social cognition, self-efficacy) to examine sustainability and the precise mechanisms of CR effects respectively.

An increased reactivity to stress in the context of daily life is suggested to be an independent risk factor underlying the positive symptoms of psychotic disorder. The aim of this study was to investigate whether positive symptoms moderate the association between everyday stressful events and negative affect (NA), known as stress reactivity. This hypothesis was put to the test in patients with a diagnosis of psychotic disorder.

The Comprehensive Assessment of Symptoms and History (CASH) and the Positive and Negative Syndrome Scale (PANSS) were used to assess positive and negative symptoms. The experience sampling method (ESM), a structured diary technique, was used to measure stress reactivity and psychotic symptoms in daily life.

Higher levels of positive symptoms (CASH: B = 0.14, p = 0.005; PANSS: B = 0.05, p = 0.000; ESM: B = 0.03, p = 0.000) and lower levels of negative symptoms (PANSS: B = − 0.05, p = 0.001) significantly moderate the association between unpleasant events and NA. No significant moderating effect was found for CASH negative symptoms. Moreover, the moderating effect of lifetime and current symptoms on the stress–NA association was significantly larger for those patients with predominantly positive symptoms (CASH: B = 0.09, p = 0.000; PANSS: B = 0.08, p = 0.000; ESM: B = 0.13, p = 0.000).

Patients with a ‘psychotic syndrome’ with high levels of positive symptoms and low levels of negative symptoms show increased reactivity to stress in daily life, indicating that stress reactivity is a possible risk factor underlying this syndrome.

Distorted images of the observable self are considered crucial in the development and maintenance of social anxiety. We generated an experimental situation in which participants viewed themselves from an observer's perspective when exposed to scrutiny and evaluation by others.

Twenty patients with social anxiety disorder (SAD) and 20 control subjects were assessed using functional magnetic resonance imaging (fMRI) during the public exposure of pre-recorded videos in which they were each shown performing a verbal task. The examiners acted as the audience in the experiment and rated performance. Whole-brain functional maps were computed using Statistical Parametric Mapping.

Robust activation was observed in regions related to self-face recognition, emotional response and general arousal in both study groups. Patients showed significantly greater activation only in the primary visual cortex. By contrast, they showed significant deactivation or smaller activation in dorsal frontoparietal and anterior cingulate cortices relevant to the cognitive control of negative emotion. Task-related anxiety ratings revealed a pattern of negative correlation with activation in this frontoparietal/cingulate network. Importantly, the relationship between social anxiety scores and neural response showed an inverted-U function with positive correlations in the lower score range and negative correlations in the higher range.

Our findings suggest that exposure to scrutiny and evaluation in SAD may be associated with changes in cortical systems mediating the cognitive components of anxiety. Disorder severity seems to be relevant in shaping the neural response pattern, which is distinctively characterized by a reduced cortical response in the most severe cases.

Help seeking for online peer and other social support in response to depression and other mental health problems offers an electronic technology alternative to traditional mental health care. Here, with nationally representative samples of adult community residents in the USA, we study online peer support help seeking, estimate its occurrence, and investigate depression and other suspected predictors and correlates, some of which might prove to be causal influences.

The data are from nationally representative probability sample surveys of the non-institutionalized US adult population, with a new independent sample assessed via confidential computerized self-assessment modules each year from 2004 to 2010, yielding estimates about online peer support. A total of 264 431 adults participated in these years.

An estimated three per 1000 adults (0.3%) seek online peer support for mental health problems each year (95% confidence interval 0.0022–0.0036). Individuals with depression and/or serious psychological distress are strongly over-represented among these adult online peer support help seekers (odds ratio >7, p < 0.001). Associations with college education, being non-Hispanic white, being female, and age are also noteworthy (p < 0.05).

Online help seeking for mental health social support is becoming frequent enough for study in large sample national surveys, and might well be fostered by active neuropsychiatric ailments such as depression or other serious psychological distress. Open questions remain about whether the result is beneficial, or conditions required for efficacious online peer support, as might be disclosed in definitive evidence from randomized controlled trials.

Lack of coordination between screening studies for common mental disorders in primary care and community epidemiological samples impedes progress in clinical epidemiology. Short screening scales based on the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI), the diagnostic interview used in community epidemiological surveys throughout the world, were developed to address this problem.

Expert reviews and cognitive interviews generated CIDI screening scale (CIDI-SC) item pools for 30-day DSM-IV-TR major depressive episode (MDE), generalized anxiety disorder (GAD), panic disorder (PD) and bipolar disorder (BPD). These items were administered to 3058 unselected patients in 29 US primary care offices. Blinded SCID clinical reinterviews were administered to 206 of these patients, oversampling screened positives.

Stepwise regression selected optimal screening items to predict clinical diagnoses. Excellent concordance [area under the receiver operating characteristic curve (AUC)] was found between continuous CIDI-SC and DSM-IV/SCID diagnoses of 30-day MDE (0.93), GAD (0.88), PD (0.90) and BPD (0.97), with only 9–38 questions needed to administer all scales. CIDI-SC versus SCID prevalence differences are insignificant at the optimal CIDI-SC diagnostic thresholds (χ21 = 0.0–2.9, p = 0.09–0.94). Individual-level diagnostic concordance at these thresholds is substantial (AUC 0.81–0.86, sensitivity 68.0–80.2%, specificity 90.1–98.8%). Likelihood ratio positive (LR+) exceeds 10 and LR− is 0.1 or less at informative thresholds for all diagnoses.

CIDI-SC operating characteristics are equivalent (MDE, GAD) or superior (PD, BPD) to those of the best alternative screening scales. CIDI-SC results can be compared directly to general population CIDI survey results or used to target and streamline second-stage CIDIs.

Several neuroimaging studies have investigated brain grey matter in people with body dysmorphic disorder (BDD), showing possible abnormalities in the limbic system, orbitofrontal cortex, caudate nuclei and temporal lobes. This study takes these findings forward by investigating white matter properties in BDD compared with controls using diffusion tensor imaging. It was hypothesized that the BDD sample would have widespread significantly reduced white matter connectivity as characterized by fractional anisotropy (FA).

A total of 20 participants with BDD and 20 healthy controls matched on age, gender and handedness underwent diffusion tensor imaging. FA, a measure of water diffusion within a voxel, was compared between groups on a voxel-by-voxel basis across the brain using tract-based spatial statistics within the FSL package.

Results showed that, compared with healthy controls, BDD patients demonstrated significantly lower FA (p < 0.05) in most major white matter tracts throughout the brain, including in the superior longitudinal fasciculus, inferior fronto-occipital fasciculus and corpus callosum. Lower FA levels could be accounted for by increased radial diffusivity as characterized by eigenvalues 2 and 3. No area of higher FA was found in BDD.

This study provided the first evidence of compromised white matter integrity within BDD patients. This suggests that there are inefficient connections between different brain areas, which may explain the cognitive and emotion regulation deficits within BDD patients.

Prevalence rates of post-traumatic stress disorder (PTSD) following the experience of war have been shown to be high. However, little is known about the course of the disorder in people who remained in the area of conflict and in refugees.

We studied a representative sample of 522 adults with war-related PTSD in five Balkan countries and 215 compatriot refugees in three Western European countries. They were assessed on average 8 years after the war and reinterviewed 1 year later. We established change in PTSD symptoms, measured on the Impact of Events Scale – Revised (IES-R), and factors associated with more or less favourable outcomes.

During the 1-year period, symptoms decreased substantially in both Balkan residents and in refugees. The differences were significant for IES-R total scores and for the three subscales of intrusions, avoidance and hyperarousal. In multivariable regressions adjusting for the level of baseline symptoms, co-morbidity with depression predicted less favourable symptom change in Balkan residents. More pre-war traumatic events and the use of mental health services within the follow-up period were associated with less improvement in refugees.

Several years after the war, people with PTSD reported significant symptom improvement that might indicate a fluctuating course over time. Co-morbid depression may have to be targeted in the treatment of people who remained in the post-conflict regions whereas the use of mental health services seems to be linked to the persistence of symptoms among refugees.

Prior studies have suggested that major depressive disorder (MDD) with pre-adult onset represents a distinct subtype with greater symptom severity and higher rates of suicidal ideation. Whether these patients have poorer response to various types of antidepressant treatment than those with adult-onset MDD is unclear.

A total of 665 psychiatric and primary care out-patients (aged 18–75 years) with non-psychotic chronic or recurrent MDD participated in a single-blind, randomized trial that compared the efficacy of escitalopram plus placebo, bupropion sustained-release plus escitalopram, or venlafaxine extended-release plus mirtazapine. We compared participants who self-reported MDD onset (before age 18) to those with a later onset (adult onset) with respect to baseline characteristics and treatment/outcome variables at 12 and 28 weeks.

Early-onset chronic/recurrent MDD was associated with a distinct set of sociodemographic (female, younger age) and clinical correlates (longer duration of illness, greater number of prior episodes, greater likelihood of atypical features, higher rates of suicidality and psychiatric co-morbidity, fewer medical problems, poorer quality of life, greater history of child abuse/neglect). However, results from unadjusted and adjusted analyses showed no significant differences in response, remission, tolerability of medications, quality of life, or retention at 12 or 28 weeks.

Although early-onset chronic/recurrent MDD is associated with a more severe clinical picture, it does not seem to be useful for predicting differential treatment response to antidepressant medication. Clinicians should remain alert to an increased risk of suicidality in this population.

Emotion dysregulation is a key feature of schizophrenia, a brain disorder strongly associated with genetic risk and aberrant dopamine signalling. Dopamine is inactivated by catechol-O-methyltransferase (COMT), whose gene contains a functional polymorphism (COMT Val158Met) associated with differential activity of the enzyme and with brain physiology of emotion processing. The aim of the present study was to investigate whether genetic risk for schizophrenia and COMT Val158Met genotype interact on brain activity during implicit and explicit emotion processing.

A total of 25 patients with schizophrenia, 23 healthy siblings of patients and 24 comparison subjects genotyped for COMT Val158Met underwent functional magnetic resonance imaging during implicit and explicit processing of facial stimuli with negative emotional valence.

We found a main effect of diagnosis in the right amygdala, with decreased activity in patients and siblings compared with control subjects. Furthermore, a genotype × diagnosis interaction was found in the left middle frontal gyrus, such that the effect of genetic risk for schizophrenia was evident in the context of the Val/Val genotype only, i.e. the phenotype of reduced activity was present especially in Val/Val patients and siblings. Finally, a complete inversion of the COMT effect between patients and healthy subjects was found in the left striatum during explicit processing.

Overall, these results suggest complex interactions between genetically determined dopamine signalling and risk for schizophrenia on brain activity in the prefrontal cortex during emotion processing. On the other hand, the effects in the striatum may represent state-related epiphenomena of the disorder itself.

Early life stress (ELS) is a significant risk factor for depression. The effects of ELS exposure on neural network organization have not been differentiated from the effect of depression. Furthermore, many individuals exposed to ELS do not develop depression, yet the network organization patterns differentiating resiliency versus susceptibility to the depressogenic effects of ELS are not clear.

Women aged 18–44 years with either a history of ELS and no history of depression (n = 7), a history of ELS and current or past depression (n = 19), or a history of neither ELS nor depression (n = 12) underwent a resting-state 3-T functional magnetic resonance imaging (fMRI) scan. An emotion regulation brain network consisting of 21 nodes was described using graph analyses and compared between groups.

Group differences in network topology involved decreased global connectivity and hub-like properties for the right ventrolateral prefrontal cortex (vlPFC) and decreased local network connectivity for the dorsal anterior cingulate cortex (dACC) among resilient individuals. Decreased local connectivity and increased hub-like properties of the left amygdala, decreased hub-like properties of the dACC and decreased local connectivity of the left vlPFC were observed among susceptible individuals. Regression analyses suggested that the severity of ELS (measured by self-report) correlated negatively with global connectivity and hub-like qualities for the left dorsolateral PFC (dlPFC).

These preliminary results suggest functional neural connectivity patterns specific to ELS exposure and resiliency versus susceptibility to the depressogenic effects of ELS exposure.

Accumulating evidence suggests that fetal growth restriction may increase risk of later schizophrenia but this issue has not been addressed directly in previous studies. We examined whether the degree of fetal growth restriction was linearly related to risk of schizophrenia, and also whether maternal pre-eclampsia, associated with both placental dysfunction and poor fetal growth, was related to risk of schizophrenia.

A population-based cohort of single live births in the Medical Birth Registry of Norway (MBRN) between 1967 and 1982 was followed to adulthood (n = 873 612). The outcome was schizophrenia (n=2207) registered in the National Insurance Scheme (NIS). The degree of growth restriction was assessed by computing sex-specific z scores (standard deviation units) of ‘birth weight for gestational age’ and ‘birth length for gestational age’. Analyses were adjusted for potential confounders. Maternal pre-eclampsia was recorded in the Medical Birth Registry by midwives or obstetricians using strictly defined criteria.

The odds ratio (OR) for schizophrenia increased linearly with decreasing birth weight for gestational age z scores (p value for trend = 0.005). Compared with the reference group (z scores 0.01–1.00), the adjusted OR [95% confidence interval (CI)] for the lowest z-score category (< − 3.00) was 2.0 (95% CI 1.2–3.5). A similar pattern was observed for birth length for gestational age z scores. Forty-nine individuals with schizophrenia were identified among 15 622 births with pre-eclampsia. The adjusted OR for schizophrenia following maternal pre-eclampsia was 1.3 (95% CI 1.0–1.8).

Associations of schizophrenia risk with degree of fetal growth restriction and pre-eclampsia suggest future research into schizophrenia etiology focusing on mechanisms that influence fetal growth, including placental function.