Can breast-feeding protect against schizophrenia? Case-control Study

Establishing associated risk factors, including fungal and parasitic infections among Malaysians living with schizophrenia

The aetiology of schizophrenia is multifactorial, and the identification of its risk factors are scarce and highly variable. A cross-sectional study was conducted to investigate the risk factors associated with schizophrenia among Malaysian sub-population. A total of 120 individuals diagnosed with schizophrenia (SZ) and 180 non-schizophrenic (NS) individuals participated in a questionnaire-based survey. Data of complete questionnaire responses obtained from 91 SZ and 120 NS participants were used in statistical analyses. Stool samples were obtained from the participants and screened for gut parasites and fungi using conventional polymerase chain reaction (PCR). The median age were 46 years (interquartile range (IQR) 37 to 60 years) and 35 years (IQR 24 to 47.75 years) for SZ and NS respectively. Multivariable binary logistic regression showed that the factors associated with increased risk of SZ were age, sex, unemployment, presence of other chronic ailment, smoking, and high dairy consumption per week. These factors, except sex, were positively associated with the severity of SZ. Breastfed at infancy as well as vitamin and supplement consumption showed a protective effect against SZ. After data clean-up, fungal or parasitic infections were found in 98% (39/42). of SZ participants and 6.1% (3/49) of NS participants. Our findings identified non-modifiable risk factors (age and sex) and modifiable lifestyle-related risk factors (unemployment, presence of other chronic ailment, smoking, and high dairy consumption per week) associated with SZ and implicate the need for medical attention in preventing fungal and parasitic infections in SZ.

Association of breastfeeding with mental disorders in mother and child: a systematic review and meta-analysis

BACKGROUND

Breastfeeding has long been associated with numerous benefits for both mothers and infants. While some observational studies have explored the relationship between breastfeeding and mental health outcomes in mothers and children, a systematic review of the available evidence is lacking. The purpose of this study is to systematically evaluate the association between breastfeeding and mental health disorders in mothers and children.

METHODS

We systematically searched MEDLINE and EMBASE from inception to June 2, 2023. The inclusion criteria consisted of all studies evaluating links between breastfeeding and development of mental health disorders in children and mothers. Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) while grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of evidence. A random-effects meta-analysis was used if possible, to estimate the odds ratio for the association between breastfeeding and mental health outcomes. The Mantel-Haenszel method was utilised for pooling ORs across studies. Study heterogeneity was assessed using the I2 statistic.

RESULTS

Our review identified twenty-one original study. Of these, 18 focused on the association between breastfeeding and child health, assessing depressive disorders, schizophrenia, anxiety disorders, eating disorders and borderline personality disorder. Three studies evaluated the associations between breastfeeding and maternal mental health disorders. Three studies looking at outcomes in children showed no significant association between breastfeeding and occurrence of schizophrenia later in life (OR 0.98; 95% CI 0.57-1.71; I2 = 29%). For depressive disorders (5 studies) and anxiety disorders (3 studies), we found conflicting evidence with some studies showing a small protective effect while others found no effect. The GRADE certainty for all these findings was very low due to multiple limitations. Three studies looking at association between breastfeeding and maternal mental health, were too heterogeneous to draw any firm conclusions.

CONCLUSIONS

We found limited evidence to support a protective association between breastfeeding and the development of mental health disorders in children later in life. The data regarding the association between breastfeeding and maternal mental health beyond the postnatal period is also limited. The methodological limitations of the published literature prevent definitive conclusions, and further research is needed to better understand the relationship between breastfeeding and mental health in mothers and children.

Breastfeeding duration is associated with larger cortical gray matter volumes in children from the ABCD study

BACKGROUND

Despite the numerous studies in favor of breastfeeding for its benefits in cognition and mental health, the long-term effects of breastfeeding on brain structure are still largely unknown. Our main objective was to study the relationship between breastfeeding duration and cerebral gray matter volumes. We also explored the potential mediatory role of brain volumes on behavior.

METHODS

We analyzed 7,860 magnetic resonance images of children 9-11 years of age from the Adolescent Brain Cognitive Development (ABCD) dataset in order to study the relationship between breastfeeding duration and cerebral gray matter volumes. We also obtained several behavioral data (cognition, behavioral problems, prodromal psychotic experiences, prosociality, impulsivity) to explore the potential mediatory role of brain volumes on behavior.

RESULTS

In the 7,860 children analyzed (median age = 9 years and 11 months; 49.9% female), whole-brain voxel-based morphometry analyses revealed an association mainly between breastfeeding duration and larger bilateral volumes of the pars orbitalis and the lateral orbitofrontal cortex. In particular, the association with the left pars orbitalis and the left lateral orbitofrontal cortex proved to be very robust to the addition of potentially confounding covariates, random selection of siblings, and splitting the sample in two. The volume of the left pars orbitalis and the left lateral orbitofrontal cortex appeared to mediate the relationship between breastfeeding duration and the negative urgency dimension of the UPPS-P Impulsive Behavior Scale. Global gray matter volumes were also significant mediators for behavioral problems as measured with the Child Behavior Checklist.

CONCLUSIONS

Our findings suggest that breastfeeding is a relevant factor in the proper development of the brain, particularly for the pars orbitalis and lateral orbitofrontal cortex regions. This, in turn, may impact impulsive personality and mental health in early puberty.

The Association Between Breastfeeding Exposure and Duration, Neuropsychological Deficits, and Psychopathic Personality Traits in Offspring: The Moderating Role of 5HTTLPR

A wealth of research has revealed that a shorter duration of breastfeeding during infancy can increase the risk of various maladaptive traits, including neuropsychological deficits. Despite the number of studies that have been conducted on the topic, few studies have explored whether the effects of breastfeeding on neuropsychological functioning and personality features persist into adulthood. Furthermore, very little research to date has examined whether this relationship is moderated by specific indicators of genetic risk. The current study examines the direct and interactive effects of breastfeeding experiences and the serotonin transporter polymorphism (5HTTLPR) on neuropsychological deficits and psychopathic personality traits. Using data from the National Longitudinal study of Adolescent Health, we find that no exposure to breastfeeding and a shorter duration of breastfeeding significantly increase the risk of exhibiting neuropsychological deficits during adolescence and early adulthood as well as psychopathic personality traits during adulthood. The results also reveal a number of gene × environment interactions between 5HTTLPR, breastfeeding exposure and breastfeeding duration in the prediction of neuropsychological deficits, but not in the prediction of psychopathic personality traits.

Polyunsaturated fatty acids and their metabolites in the pathobiology of schizophrenia

Schizophrenia can be considered as a low-grade systemic inflammatory disease with its origins in the perinatal period. It is likely that genetic, environmental, and nutritional factors interact to induce excess production of pro-inflammatory cytokines that, in turn, damage fetal neurons leading to the adult onset of schizophrenia. Polyunsaturated fatty acids (PUFAs) and their metabolites such as lipoxins, resolvins, protectins, maresins and nitrolipids not only have potent neuroprotective action but also are capable of inhibiting the production of pro-inflammatory cytokines. Decreased formation of PUFAs as a result of low activity of Δ(6) and Δ(5) desaturases can result in an increase in the production of pro-inflammatory cytokines due to the absence of negative control exerted by PUFAs and their anti-inflammatory metabolites that, in turn, may predispose to neuronal damage and development of schizophrenia in adult life. Furthermore, PUFAs are essential for brain growth and development. If this proposal is correct, this implies that perinatal and adult supplementation of PUFAs not only prevents but also helps in the treatment of schizophrenia. Furthermore, synthetic analogs of lipoxins, resolvins, and protectins may be of significant benefit in schizophrenia.

Nurses' attitudes towards breastfeeding among women with schizophrenia in southern Israel

Breastfeeding is the best source of nutrition for infants. Approximately half of women with schizophrenia become mothers, yet the issue of breastfeeding is often overlooked by the health professional community. The aim of this study was to survey attitudes among registered nurses regarding breastfeeding by schizophrenic women. Cross-sectional descriptive design was used involving a sample of nurses (40 midwives, 37 psychiatric and 33 postpartum) in two medical centres in southern Israel. The validated semistructured questionnaire included sociodemographic and professional questions, personal and professional breastfeeding experience, attitudes and knowledge concerning schizophrenia and attitudes towards breastfeeding by schizophrenic women. The study results indicate that 70% of the respondents held positive attitudes towards breastfeeding in women with schizophrenia, although no significant differences were found between the different types of nurses. Multivariate analysis reveals that academic education was the only variable associated with positive attitudes, while negative feelings towards women with schizophrenia, and extensive knowledge regarding schizophrenia were negatively associated. This study can serve as a foundation for future research to further examine nurses' role in providing postpartum education and care for women with schizophrenia.

Beyond the first episode: candidate factors for a risk prediction model of schizophrenia

Many early psychosis services are financially compromised and cannot offer a full tenure of care to all patients. To maintain viability of services it is important that those with schizophrenia are identified early to maximize long-term outcomes, as are those with better prognoses who can be discharged early. The duration of untreated psychosis remains the mainstay in determining those who will benefit from extended care, yet its ability to inform on prognosis is modest in both the short and medium term. There are a number of known or putative genetic and environmental risk factors that have the potential to improve prognostication, though a multivariate risk prediction model combining them with clinical characteristics has yet to be developed. Candidate risk factors for such a model are presented, with an emphasis on environmental risk factors. More work is needed to corroborate many putative factors and to determine which of the established factors are salient and which are merely proxy measures. Future research should help clarify how gene-environment and environment-environment interactions occur and whether risk factors are dose-dependent, or if they act additively or synergistically, or are redundant in the presence (or absence) of other factors.

Role of omega-3 fatty acids in brain development and function: potential implications for the pathogenesis and prevention of psychopathology

The principle omega-3 fatty acid in brain, docosahexaenoic acid (DHA), accumulates in the brain during perinatal cortical expansion and maturation. Animal studies have demonstrated that reductions in perinatal brain DHA accrual are associated with deficits in neuronal arborization, multiple indices of synaptic pathology including deficits in serotonin and mesocorticolimbic dopamine neurotransmission, neurocognitive deficits, and elevated behavioral indices of anxiety, aggression, and depression. In primates and humans, preterm delivery is associated with deficits in fetal cortical DHA accrual, and children/adolescents born preterm exhibit deficits in cortical gray matter maturation, neurocognitive deficits particularly in the realm of attention, and increased risk for attention-deficit/hyperactivity disorder (ADHD) and schizophrenia. Individuals diagnosed with ADHD or schizophrenia exhibit deficits in cortical gray matter maturation, and medications found to be efficacious in the treatment of these disorders increase cortical and striatal dopamine neurotransmission. These associations in conjunction with intervention trials showing enhanced cortical visual acuity and cognitive outcomes in preterm and term infants fed DHA, suggest that perinatal deficits in brain DHA accrual may represent a preventable neurodevelopmental risk factor for the subsequent emergence of psychopathology.

Breastfeeding and risk of schizophrenia in the Copenhagen Perinatal Cohort

OBJECTIVE

The aim was to study whether early weaning from breastfeeding may be associated with increased risk of schizophrenia.

METHOD

The current sample comprises 6841 individuals from the Copenhagen Perinatal Cohort of whom 1671 (24%) had been breastfed for 2 weeks or less (early weaning) and 5170 (76%) had been breastfed longer. Maternal schizophrenia, parental social status, single mother status and gender were included as covariates in a multiple regression analysis of the effect of early weaning on the risk of hospitalization with schizophrenia.

RESULTS

The sample comprised 93 cases of schizophrenia (1.4%). Maternal schizophrenia was the strongest risk factor and a significant association between single mother status and elevated offspring risk of schizophrenia was also observed. Early weaning was significantly related to later schizophrenia in both unadjusted and adjusted analyses (adjusted odds ratio 1.73 with 95% CI: 1.13-2.67).

CONCLUSION

No or <2 weeks of breastfeeding was associated with elevated risk of schizophrenia. The hypothesis of some protective effect of breastfeeding against the risk of later schizophrenia is supported by our data.

Environmental factors and membrane polyunsaturated fatty acids in schizophrenia

There is accumulating evidence of reductions in red blood cell membrane essential fatty acids in patients with schizophrenia. The mechanisms that may underlie these reductions have yet to be determined. It is possible that the observed membrane fatty acid deficits are associated with the development of schizophrenia. Alternatively, the membrane fatty acid deficits may be due to environmental factors, such as smoking and variations in diet, which may not be associated specifically with the pathophysiology of schizophrenia. Patients with schizophrenia smoke cigarettes at very high rates. Cigarette smoke contains many pro-oxidants that contribute directly to oxidative stress. Polyunsaturated fatty acids (PUFAs) are very susceptible to oxidative effects of free radicals. Thus, smoke-induced oxidative stress could plausibly account for reductions in membrane fatty acid in schizophrenia. Recent studies provide conflicting evidence for smoking effects on membrane fatty acid deficits. Likewise, the effects of diet on membrane PUFAs in schizophrenia are not entirely clear. Essential PUFAs need to be consumed in diet. Thus, differences in membrane PUFAs observed between patients and control subjects may be due to dietary variation. Few studies that have examined dietary effects differ in their interpretation of the effects of diet on membrane PUFAs. Thus, the jury is still out whether smoking or dietary effects are the primary causes of membrane PUFA deficits in patients with schizophrenia. Future studies will need to systematically examine the potential effects of smoking and diet, as well as other environmental factors such exercise, to definitively establish whether or not PUFA abnormalities are inherent to schizophrenia.