Country-level gender inequality is associated with structural differences in the brains of women and men.

Gender inequality across the world has been associated with a higher risk to mental health problems and lower academic achievement in women compared to men. We also know that the brain is shaped by nurturing and adverse socio-environmental experiences. Therefore, unequal exposure to harsher conditions for women compared to men in gender-unequal countries might be reflected in differences in their brain structure, and this could be the neural mechanism partly explaining women's worse outcomes in gender-unequal countries. We examined this through a random-effects meta-analysis on cortical thickness and surface area differences between adult healthy men and women, including a meta-regression in which country-level gender inequality acted as an explanatory variable for the observed differences. A total of 139 samples from 29 different countries, totaling 7,876 MRI scans, were included. Thickness of the right hemisphere, and particularly the right caudal anterior cingulate, right medial orbitofrontal, and left lateral occipital cortex, presented no differences or even thicker regional cortices in women compared to men in gender-equal countries, reversing to thinner cortices in countries with greater gender inequality. These results point to the potentially hazardous effect of gender inequality on women's brains and provide initial evidence for neuroscience-informed policies for gender equality.

A five-year follow-up of the verbal memory performance of individuals with bipolar disorder and schizophrenia: evidence of unchanging deficits under treatment.

OBJECTIVE: Bipolar disorder (BD) and schizophrenia (SZ) are chronic and heterogeneous mental disorders that present cognitive and functional impairments. Verbal memory is considered an important predictor of functioning and a domain vulnerable to the aging process. However, only few studies investigate the progression of memory longitudinally in BD and SZ, especially in lower- and middle-income countries. Therefore, we aim to evaluate the course of verbal memory in individuals with BD and SZ. METHODS: We assessed 31 individuals with BD and 27 individuals with SZ under treatment at outpatient clinics at baseline and after five years. They were assessed through a sociodemographic questionnaire, memory and estimated IQ (eIQ) instruments, and clinical scales. RESULTS: Individuals with SZ showed worse verbal memory performance in comparison to BD, however, we did not observe changes over time within patient groups. Individuals with BD with higher eIQ showed a better verbal memory performance, while no effect of eIQ was found for subjects with SZ. CONCLUSION: Patients with SZ and BD showed different levels of verbal memory impairment, although they had similar unchanging trajectories after 5 years under psychiatric treatment. This finding indicates a relative stable cognitive course for both disorders.

Obstetric complications and cognition in schizophrenia: a systematic review and meta-analysis.

BACKGROUND: Schizophrenia (SZ) is a complex brain disorder linked to cognitive and neurostructural abnormalities that involves genetic and environmental factors with obstetric complications (OCs) at birth conferring a high risk for the disease. Indeed, current research in the general population describes the deleterious effect of OCs on cognitive performance in adulthood. With this rationale, we aim to review the relationship between OCs and cognition in SZ and related psychotic disorders. METHODS: A systematic review and meta-analysis describing cognitive function and OCs in patients with SZ and related disorders were conducted. PubMed, EmBase, SCOPUS, and the Cochrane Library were systematically searched to identify eligible studies up to January 2022. We calculated the effect sizes (Hedges' g) of cognitive domains within each study and quantified the proportion of between-study variability using the I2 statistic. Homogeneity was assessed using the Q-statistic (X2). The study was registered on PROSPERO (CRD42018094238). RESULTS: A total of 4124 studies were retrieved, with 10 studies meeting inclusion criteria for the systematic review and eight for meta-analysis. SZ subjects with OCs showed poor verbal memory [Hedges' g = -0.89 (95% CI -1.41 to -0.37), p < 0.001] and working memory performance [Hedges' g = -1.47 (95% CI -2.89 to -0.06), p = 0.01] in a random-effect model compared to those without OCs. CONCLUSIONS: OCs appear to have a moderate impact on specific cognitive such as working memory and verbal memory. Our findings suggest that OCs are associated with brain development and might underlie the cognitive abnormalities described at onset of psychosis.

Effects of socioeconomic status in cognition of people with schizophrenia: results from a Latin American collaboration network with 1175 subjects.

BACKGROUND: Cognition heavily relies on social determinants and genetic background. Latin America comprises approximately 8% of the global population and faces unique challenges, many derived from specific demographic and socioeconomic variables, such as violence and inequality. While such factors have been described to influence mental health outcomes, no large-scale studies with Latin American population have been carried out. Therefore, we aim to describe the cognitive performance of a representative sample of Latin American individuals with schizophrenia and its relationship to clinical factors. Additionally, we aim to investigate how socioeconomic status (SES) relates to cognitive performance in patients and controls. METHODS: We included 1175 participants from five Latin American countries (Argentina, Brazil, Chile, Colombia, and Mexico): 864 individuals with schizophrenia and 311 unaffected subjects. All participants were part of projects that included cognitive evaluation with MATRICS Consensus Cognitive Battery and clinical assessments. RESULTS: Patients showed worse cognitive performance than controls across all domains. Age and diagnosis were independent predictors, indicating similar trajectories of cognitive aging for both patients and controls. The SES factors of education, parental education, and income were more related to cognition in patients than in controls. Cognition was also influenced by symptomatology. CONCLUSIONS: Patients did not show evidence of accelerated cognitive aging; however, they were most impacted by a lower SES suggestive of deprived environment than controls. These findings highlight the vulnerability of cognitive capacity in individuals with psychosis in face of demographic and socioeconomic factors in low- and middle-income countries.

Structural brain abnormalities in schizophrenia in adverse environments: examining the effect of poverty and violence in six Latin American cities.

BACKGROUND: Social and environmental factors such as poverty or violence modulate the risk and course of schizophrenia. However, how they affect the brain in patients with psychosis remains unclear. AIMS: We studied how environmental factors are related to brain structure in patients with schizophrenia and controls in Latin America, where these factors are large and unequally distributed. METHOD: This is a multicentre study of magnetic resonance imaging in patients with schizophrenia and controls from six Latin American cities. Total and voxel-level grey matter volumes, and their relationship with neighbourhood characteristics such as average income and homicide rates, were analysed with a general linear model. RESULTS: A total of 334 patients with schizophrenia and 262 controls were included. Income was differentially related to total grey matter volume in both groups (P = 0.006). Controls showed a positive correlation between total grey matter volume and income (R = 0.14, P = 0.02). Surprisingly, this relationship was not present in patients with schizophrenia (R = -0.076, P = 0.17). Voxel-level analysis confirmed that this interaction was widespread across the cortex. After adjusting for global brain changes, income was positively related to prefrontal cortex volumes only in controls. Conversely, the hippocampus in patients with schizophrenia, but not in controls, was relatively larger in affluent environments. There was no significant correlation between environmental violence and brain structure. CONCLUSIONS: Our results highlight the interplay between environment, particularly poverty, and individual characteristics in psychosis. This is particularly important for harsh environments such as low- and middle-income countries, where potentially less brain vulnerability (less grey matter loss) is sufficient to become unwell in adverse (poor) environments.

The Relationship between Cytokines and Verbal Memory in Individuals with Schizophrenia and Their Unaffected Siblings.

BACKGROUND: Verbal memory impairment may be considered an endophenotype in schizophrenia (SZ), also affecting the siblings of SZ subjects. Furthermore, the immune-inflammatory system response has an important modulatory effect on brain processes, especially on memory circuits. OBJECTIVE: Investigating the relationship between TNF-α and IL-6 and memory performance in patients with SZ, their unaffected siblings (SB) and healthy controls (HC). METHODS: 35 subjects with SZ, 36 SB, and 47 HC underwent a neurocognitive assessment for verbal memory by means of the revised Hopkins Verbal Learning Test (HVLT-R) in addition to serum cytokines analyses. RESULTS: SZ patients performed worse in HVLT-R than SB and HC, but SB and HC were not different. Regarding the biomarker levels, we found significant results of TNF-α for both groups. However, we did not find differences between groups after multiple-comparisons analysis. There were no significant correlations between episodic verbal memory, TNF-α, and IL-6. CONCLUSION: The results are compatible with the hypothesis that deficits in verbal memory of individuals with SZ could be secondary to inadequate functioning of cognitive processing areas, such as proactive cognitive control.

Mediator effects of parameters of inflammation and neurogenesis from a N-acetyl cysteine clinical-trial for bipolar depression.

OBJECTIVE: This study aimed to explore effects of adjunctive treatment with N-acetyl cysteine (NAC) on markers of inflammation and neurogenesis in bipolar depression. METHODS: This is a secondary analysis of a placebo-controlled randomised trial. Serum samples were collected at baseline, week 8, and week 32 of the open-label and maintenance phases of the clinical trial to determine changes in interleukin (IL)-6, IL-8, IL-10, tumour necrosis factor-α (TNF-α), C-reactive protein (CRP) and brain-derived neurotrophic factor (BDNF) following adjunctive NAC treatment, and to explore mediation and moderator effects of the listed markers. RESULTS: Levels of brain-derived neurotrophic factor (BDNF), tumour necrosis factor-α (TNF-α), C-reactive protein (CRP), interleukins (IL) -6, 8, or 10 were not significantly changed during the course of the trial or specifically in the open-label and maintenance phases. There were no mediation or moderation effects of the biological factors on the clinical parameters. CONCLUSION: The results suggest that these particular biological parameters may not be directly involved in the therapeutic mechanism of action of adjunctive NAC in bipolar depression.

α-Lipoic Acid as Adjunctive Treatment for Schizophrenia: An Open-Label Trial.

PURPOSE/BACKGROUND: Accumulating evidence suggests an involvement of oxidative stress in the pathophysiology of schizophrenia. This offers a hypothesis-derived therapeutic approach to hinder oxidative damage and its clinical sequelae. α-Lipoic acid (ALA) is a powerful natural antioxidant indicated to treat diabetic neuropathy. METHODS/PROCEDURES: In this pilot investigation, we administered ALA (100 mg/d) for 4 months, as an adjunct to antipsychotic medication, to 10 patients with schizophrenia. FINDINGS/RESULTS: We found robust improvement in measures of psychopathology (63.9% reduction in Brief Psychiatric Rating Scale scores), neurocognitive parameters, extrapyramidal symptoms, and decreased lipid peroxidation. IMPLICATIONS/CONCLUSIONS: If larger, double-blind, placebo-controlled studies confirm these preliminary findings, ALA could prove useful as adjunctive therapy for schizophrenia.

Effects of omega-3 supplementation on interleukin and neurotrophin levels in an animal model of schizophrenia.

New studies suggest that polyunsaturated fatty acids, such as omega-3, may reduce the symptoms of schizophrenia. The present study evaluated the preventive effect of omega-3 on interleukines (IL) and neurotrophin brain-derived neurotrophic factor (BDNF) levels in the brains of young rats subjected to a model of schizophrenia. Treatment was performed over 21 days, starting on the 30th day of rat's life. After 14 days of treatment with omega-3 or vehicle, a concomitant treatment with saline or ketamine (25 mg/kg) was started and maintained until the last day of the experiment. BDNF levels in the rat's prefrontal cortex were decreased at 1 h and 24 h after the last administration of ketamine, whereas the group administered with ketamine and omega-3 showed a decrease in BDNF levels only after 24 h. In contrast, both interventions induced similar responses in levels of IL-1ß and IL6. These findings suggest that the similarity of IL-1ß and IL6 levels in our experimental groups is due to the mechanism of action of ketamine on the immune system. More studies have to be carried out to explain this pathology. In conclusion, according to previous studies and considering the current study, we could suggest a prophylactic role of omega-3 against the outcome of symptoms associated with schizophrenia.

Early growth response 1 (EGR1) is downregulated in peripheral blood from patients with major psychiatric disorders.

OBJECTIVES: To evaluate relative expression of genes with the potential to translate environmental stimuli into long-term alterations in the brain - namely Early Growth Response (EGR)1, EGR3, and Cryptochrome Circadian Regulator 2 (CRY2) - in peripheral blood from patients with Bipolar Disorder (BD), Schizophrenia (SZ), Major Depressive Disorder (MDD) and healthy controls (HC). METHODS: Thirty individuals ranging from 18 to 60 years were recruited for each group (BD, SZ, MDD or HC) from a Brazilian public hospital. Therefore, individuals' peripheral blood was collected and EGR1, EGR3 and CRY2 gene expression analyzed by PCR Real Time. RESULTS: EGR1 mRNA levels are significantly lower in psychiatric patients when compared to HC, but there is no difference for EGR3 and CRY2. Exploring the findings for each diagnosis, there is a significant difference between each diagnosis group only for EGR1, which was lower in BD, MDD and SZ as compared to HC. No significant correlations were found between gene expression and clinical features. CONCLUSIONS: EGR1 is downregulated in psychiatric patients, regardless of the diagnosis and may be a potential common target in major psychiatric disorders. EGR1, as a transcription factor, modulates many other genes and participates in crucial neuronal and synaptic processes, such as plasticity, neurotransmitters metabolism, vesicular transport and signaling pathways. The study of EGR1 and its upstream regulators in psychiatry might lead to potential new therapeutic targets.

The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects.

BACKGROUND: The objective of this epidemiological study was to evaluate the effect of length of sunlight exposure on interleukin 6 (IL-6) levels in depressive and non-depressive subjects. METHODS: This was a cross-sectional study with 154 subjects (54 males, mean age: 43.5 ± 12.8 years) who were living in a rural area in south Brazil. Chronobiological and light parameters were assessed using the Munich Chronotype Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Depressive symptoms were assessed with the Beck Depression Inventory. Plasma levels of inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-α, and interferon) were collected during the daytime and measured. RESULTS: IL-6 levels showed a positive correlation with light exposure (r = 0.257; p < 0.001) and a negative correlation with the mid-sleep phase on work-free days (r = -0.177; p = 0.028). Multiple linear regression analysis showed that only the length of light exposure was an independent factor for predicting IL-6 levels (ß = 0.26; p = 0.002). In non-depressed subjects, exposure to a different intensity of light did not affect IL-6 levels (t = -1.6; p = 0.1). However, when the two depressive groups with low and high light exposure were compared, the low light exposure group had lower levels of IL-6 compared with the high light exposure group (t = -2.19 and p = 0.0037). CONCLUSIONS: The amount of time that participants are exposed to sunlight is directly related to their IL-6 levels. Additionally, depressed subjects differ in their IL-6 levels if they are exposed to light for differing amounts of time.

Immunoinflammatory and oxidative alterations in subjects with schizophrenia under clozapine: A meta-analysis.

Clozapine presents immunoregulatory properties not well understood. To address this issue, we performed this systematic review to evaluate the immune alterations induced by clozapine and its relationship with the drug's clinical response and compare it with other antipsychotics. Our systematic review has selected nineteen studies meeting the inclusion criteria, from which eleven were included in the meta-analysis, totalizing 689 subjects distributed over three different comparisons. The results revealed that clozapine treatment activates the compensatory immune-regulatory system (CIRS) (Hedges's g = +1.049; CI +0.62 - +1.47, p < 0.001) but has no effects on the immune-Inflammatory Response System (IRS) (Hedges's g= -0.27; CI -1.76 - +1.22, p = 0.71), M1 macrophage (Hedges's g= -0.32; CI -1.78 - +1.14, p = 0.65) and Th1 (Hedge's g = 0.86; CI -0.93 - +1.814, p = 0.07) profiles. Comparing clozapine-treated patients with other anti-psychotics-treated, plasma levels of interleukin (IL)-6 were greater in the clozapine group (Hedge's g = 0.75; CI 0.35 - 1.15, p<0.001). In addition, higher IL-6 plasma levels after four weeks of clozapine treatment were related to the development of clozapine-induced fever; however, IL-6 levels recovered to baseline in 6-10 weeks due to an unexplained compensatory mechanism. In conclusion, our results show that clozapine treatment causes a time-dependent mixed immune profile characterized by increased IL-6 levels and CIRS activation, which may contribute to this drug mechanism of action and adverse effects. Future studies must be designed to investigate the relationship between clozapine-induced immune alterations and symptom remission, treatment resistance, and adverse effects, given the importance of this drug for treating resistant schizophrenia.

Association of daily-life functioning and obesity in individuals with schizophrenia and controls.

Early weight gain following the diagnosis of schizophrenia (SCZ) has been associated with improved daily functioning. However, in the general population and in other psychiatric conditions such as bipolar disorder, increased body mass index (BMI) has been associated with worse functioning. The data on this association in chronic individuals with SCZ is still scarce. To address this gap in knowledge, our objective was to evaluate the association between BMI and psychosocial functioning in chronic outpatients with SCZ and in healthy individuals. Six-hundred individuals (n = 600), 312 with schizophrenia (SCZ) and 288 individuals with no personal or family history of severe mental illness (CTR), underwent weight, height and psychosocial functioning score (FAST) assessment. Linear regression models tested the association between FAST as dependent variable and BMI as independent variable, controlling for age, sex, use of clozapine and years of illness. In the CTR group, the highest BMI could predict a worse result in FAST, explaining about 22% of the variation found (Model: AdjR2 = 0.225 F(3,284) = 28.79 p < .001; BMI main effect: ß = 0.509 t = 9.240 p < .001). In the SCZ group, there was no statistically significant association. Our findings corroborate the perception that increased BMI is associated with worse functioning status in the general population. In chronic SCZ, whatsoever, there is no association. Our findings suggest that patients with higher BMI in the SCZ group may compensate for the possible impairment of functionality due to increased body weight, through improved adherence and responsiveness to prescribed psychopharmacological treatment, leading to better control of psychiatric symptoms.

Latin American consensus recommendations for the management and treatment of patients with treatment-resistant depression (TRD).

Despite the abundance of literature on treatment-resistant depression (TRD), there is no universally accepted definition of TRD, and available treatment pathways for the management of TRD vary across the Latin American region, highlighting the need for a uniform definition and treatment principles to optimize the management of TRD in Latin America. METHODS: Following a thematic literature review and pre-meeting survey, a Latin America expert panel comprising 14 psychiatrists with clinical experience in managing patients with TRD convened and utilized the RAND/UCLA appropriateness method to develop consensus-based recommendations on the appropriate definition of TRD and principles for its management. RESULTS: The expert panel agreed that 'treatment-resistant depression' (TRD) is defined as 'failure of two drug treatments of adequate doses, for 4-8 weeks duration with adequate adherence, during a major depressive episode'. A stepwise treatment approach should be employed for the management of TRD - treatment strategies can include maximizing dose, switching to a different class, and augmenting or combining treatments. Nonpharmacological treatments, such as electroconvulsive therapy, are also appropriate options for patients with TRD. CONCLUSION: These consensus recommendations on the operational definition of TRD and approved treatments for its management can be adapted to local contexts in the Latin American countries but should not replace clinical judgement. Individual circumstances and benefit-risk balance should be carefully considered while determining the most appropriate treatment option for patients with TRD.

The role of semantic clustering in the relationship between verbal memory and psychosocial functioning in schizophrenia and bipolar disorder: Possible distinct cognitive pathway compared to healthy controls.

BACKGROUND: Verbal memory (VM) is impaired in schizophrenia (SZ) and bipolar disorder (BD), and predicts psychosocial functioning. However, there is a lack of research exploring the role of VM component processes, including semantic clustering, in these disorders. Semantic clustering might impact this association, as effective semantic memory strategies may reflect unimpaired executive control, leading to an adequate functioning. We aimed to investigate VM components in SZ and BD, and the role of semantic clustering in the relationship between VM and functioning. METHODS: We included 495 participants (156 SZ, 172 BD, and 167 healthy controls (HC)) that underwent an assessment using the Hopkins Verbal Learning Test - Revised for VM and the Functioning Assessment Short Test for psychosocial functioning. We compared groups through ANOVAs and investigated the effect of semantic clustering in the relationship between VM total immediate free recall and functioning through linear regression models. RESULTS: SZ had worse overall VM performance compared to BD, which performed worse than HCs. HCs used more semantic clustering than SZ and BD, but there were no differences between the two clinical groups. In HCs, semantic clustering impacted the relationship between VM performance and functioning, while no interaction was observed in SZ or BD. LIMITATIONS: Cross-sectional design; no medication effects or other cognitive functions were assessed. CONCLUSIONS: SZ and BD may use an alternative cognitive pathway in which the relationship between VM and functioning is independent of complex cognitive processes such as semantic clustering, supporting the cognitive remediation targeting of VM in these disorders.

Maintenance N-acetyl cysteine treatment for bipolar disorder: a double-blind randomized placebo controlled trial.

BACKGROUND: N-acetyl cysteine (NAC) is a glutathione precursor that has been shown to have antidepressant efficacy in a placebo-controlled trial. The current study aimed to investigate the maintenance effects of NAC following eight weeks of open-label treatment for bipolar disorder. METHOD: The efficacy of a double blind randomized placebo controlled trial of 2 g/day NAC as adjunct maintenance treatment for bipolar disorder was examined. Participants (n = 149) had a Montgomery Asberg Depression Rating Score of ≥12 at trial entry and, after eight weeks of open-label NAC treatment, were randomized to adjunctive NAC or placebo, in addition to treatment as usual. Participants (primarily outpatients) were recruited through public and private services and through newspaper advertisements. Time to intervention for a mood episode was the primary endpoint of the study, and changes in mood symptoms, functionality and quality of life measures were secondary outcomes. RESULTS: There was a substantial decrease in symptoms during the eight-week open-label NAC treatment phase. During the subsequent double-blind phase, there was minimal further change in outcome measures with scores remaining low. Consequently, from this low plateau, between-group differences did not emerge on recurrence, clinical functioning or quality of life measures. CONCLUSIONS: There were no significant between-group differences in recurrence or symptomatic outcomes during the maintenance phase of the trial; however, these findings may be confounded by limitations. TRIAL REGISTRATION: The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12607000074493).

Childhood trauma, impulsivity, and executive functioning in crack cocaine users.

BACKGROUND: The use of crack cocaine is a major public health concern in Brazil and internationally. Recent data suggest that childhood trauma is associated with worse outcomes among cocaine users. This study had the objective of evaluating the relationship of childhood trauma with executive functioning and impulsivity in outpatients with crack cocaine use disorders. METHODS: This is a cross-sectional study of 84 consecutive outpatients with a primary crack cocaine use disorder who sought treatment in Porto Alegre, Brazil. Childhood trauma was evaluated with the Childhood Trauma Questionnaire; executive functioning, with the Wisconsin Card Sorting Test; and impulsivity, with the Barratt Impulsivity Scale. RESULTS: Childhood trauma was strongly associated with executive dysfunction and impulsivity, even when controlled for possible confounders. CONCLUSIONS: Childhood trauma may be associated with executive dysfunction and impulsivity in crack cocaine users. The full impact of trauma needs to be further investigated in longitudinal studies.

Clozapine prescription trends in Brazil in the last decade.

OBJECTIVE: Clozapine is a second-generation antipsychotic indicated for treatment-resistant schizophrenia. Studies in several countries have shown a low rate of clozapine use despite the fact that approximately 30% of schizophrenia cases are treatment-resistant. In Brazil, few studies have addressed the frequency and variety of antipsychotic use in individuals diagnosed with schizophrenia (ICD F20). The objective of this study was to measure the rates of clozapine use in this population in the last decade using Brazilian Ministry of Health data. METHODS: Prescriptions made between 2010 and 2020 in all 26 states and the Federal District registered at the Outpatient Information System Database from the Brazilian Health System (SIASUS) were evaluated. RESULTS: A total of 25,143,524 prescriptions were recorded in this period, with clozapine representing 8.86% of all antipsychotics. The most frequently prescribed antipsychotic for patients with schizophrenia was olanzapine (35.8%), followed by quetiapine (27.5%). From 2010 to 2020, the rate of clozapine prescriptions in Brazil increased from 7.2% to 10.9%. CONCLUSIONS: Despite a slight increase in prescriptions in the last decade, clozapine is still underutilized in Brazil.

Risk of neutropenia among clozapine users and non-users: results from 5,847 patients.

OBJECTIVE: Clozapine is underprescribed due to neutropenia risk. Blood tests every 3 months in those on continuous treatment for > 1 year who have never had an absolute neutrophil count (ANC) < 2,000/µL has been proposed as a monitoring strategy; however, there are no South American data to support this recommendation. This study sought to investigate whether clozapine use and other variables could explain the occurrence of ANC < 1,000/µL in patients with severe mental disorders. METHODS: A total of 5,847 subjects were included, 1,038 on clozapine. We performed a Cox regression considering the outcome as ANC < 1,000/µL at any time point. Predictors were sex, age, ethnicity, clozapine use, ANC > 2,000/µL during the first year of blood monitoring, and presence of a severe medical condition. RESULTS: In the Cox regression model, ethnicity (white) (hazard ratio [HR] 0.53; 95%CI 0.29-0.99, p < 0.05) and ANC > 2,000/µL (HR 0.04; 95%CI 0.01-0.10, p < 0.001) were protective factors, while presence of a severe medical condition (HR 69.35; 95%CI 37.45-128.44, p < 0.001) was a risk factor for ANC < 1,000/µL. Other variables were not significant, including clozapine use (HR 1.33; 95%CI 0.74-2.39, p > 0.05). CONCLUSIONS: These findings suggest that clozapine does not increase the risk of neutropenia in subjects with ANC > 2,000/µL during the first year of use and in the absence of a severe medical condition. These results could help guide clinical and public-health decisions regarding clozapine blood monitoring guidelines.