Significance: Our current knowledge of the pathophysiology and molecular mechanisms causing psychiatric disorders is modest, but genetic susceptibility and environmental factors are central to the etiology of these conditions. Autism, schizophrenia, bipolar disorder and major depressive disorder show genetic gene risk overlap and share symptoms and metabolic comorbidities. The identification of such common features may provide insights into the development of these disorders. Recent Advances: Multiple pieces of evidence suggest that brain energy metabolism, mitochondrial functions and redox balance are impaired to various degrees in psychiatric disorders. Since mitochondrial metabolism and redox signaling can integrate genetic and environmental environmental factors affecting the brain, it is possible that they are implicated in the etiology and progression of psychiatric disorders. Critical Issue: Evidence for direct links between cellular mitochondrial dysfunction and disease features are missing. Future Directions: A better understanding of the mitochondrial biology and its intracellular connections to the nuclear genome, the endoplasmic reticulum and signaling pathways, as well as its role in intercellular communication in the organism, is still needed. This review focuses on the findings that implicate mitochondrial dysfunction, the resultant metabolic changes and oxidative stress as important etiological factors in the context of psychiatric disorders. We also propose a model where specific pathophysiologies of psychiatric disorders depend on circuit-specific impairments of mitochondrial dysfunction and redox signaling at specific developmental stages.

Substance use among Korean adolescents has been increasing, but little is known about the correlates of substance use in this population. Identification of the correlates is required for development of preventive approaches that aim to reduce or eliminate risk. Therefore, we examined the prevalence and correlates of substance use including psychological problems in a nationwide sample of Korean adolescents. Data from the 2014 Korean Youth Risk Behavior Web-Based Survey, collected from 72,060 adolescents aged 12–18 years (mean age 14.94 ± 1.75 years), were analyzed. Participants’ lifetime experiences with substances (alcohol, tobacco, and illicit drugs) were assessed. Participants’ perceived stress, depressive mood, and suicidality during the previous 12 months were also investigated. The lifetime prevalence estimates of alcohol, tobacco, and illicit drug use were 43.0, 19.9, and 0.4 % of the participants, respectively. The most commonly used illicit drugs were inhalants. Older age, male gender, non-residence with family, low parental educational level and socio-economic status, and low academic achievement were positively and significantly associated with substance use. Substance (alcohol, tobacco, and illicit drug) use was positively and significantly associated with severe stress, depressive mood, and suicidality during the previous 12 months, with the highest odds ratios obtained from illicit drug use. These results indicate that the use of substances (alcohol, tobacco, and illicit drugs) among Korean adolescents is associated with socially disadvantaged families, psychological problems, and risky behavior. Health education including dependency prevention programs is needed for these high-risk groups.

Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential for infant neurodevelopment. The nutritional adequacy of dietary LC-PUFAs depends not only on the LC-PUFAs intake but also on the n-6 to n-3 fatty acid ratio (n-6/n-3 PUFAs). This study aimed to identify the association between the maternal dietary n-6/n-3 PUFAs and motor and cognitive development of infants at 6 months of age. We used data from 960 participants in the Mothers and Children's Environmental Health (MOCEH) study, which is a multi-center prospective cohort study. Dietary intake of pregnant women was assessed by a one-day 24-h recall method. Food consumption of infants was estimated based on the volume of breast milk and weaning foods. The duration of each feed was used to estimate the likely volume of milk consumed. Dietary intake of infants at 6 months was also assessed by a 24-h recall method. Cognitive and motor development of infants at 6 months of age was assessed by the Korean Bayley scales of infant development edition II (BSID-II) including the mental developmental index (MDI) and the psychomotor developmental index (PDI). Maternal intakes of n-6/n-3 PUFAs and linoleic acid (LA)-to-α-linolenic acid (ALA) ratio (LA/ALA) were 9.7 ± 6.3 and 11.12 ± 6.9, respectively. Multiple regression analysis, after adjusting for covariates, showed that n-6/n-3 PUFAs was negatively associated with both the MDI (β = −0.1674, P = 0.0291) and PDI (β = −0.1947, P = 0.0380) at 6 months of age. These inverse associations were also observed between LA/ALA and both the MDI and PDI (MDI; β = −0.1567; P = 0.0310, PDI; β = −0.1855; P = 0.0367). Multiple logistic regression analysis, with the covariates, showed that infants whose mother’s LA/ALA were ranked in the 2nd, 3rd, and 4th quartile were at approximately twice the risk with more than twice the risk of delayed performance on the PDI compared to the lowest quartile (1st vs. 2nd; OR = 2.965; 95% CI = 1.376 − 6.390, 1st vs. 3rd; OR = 3.047; 95% CI = 1.374 − 6.756 and 1st vs. 4th; OR = 2.551; 95% CI = 1.160 − 5.607). Both the maternal dietary n-6/n-3 PUFAs and LA/ALA intake were significantly associated with the mental and psychomotor development of infants at 6 months of age. Thus, maintaining low n-6/n-3 PUFAs and LA/ALA is encouraged for women during pregnancy.

Although there is some evidence supporting the existence of an association between prenatal maternal or postnatal child’s urine phthalate metabolite concentrations and poor attentional performances, the interaction between urine phthalate metabolite levels and genetic variation for neuropsychological deficit of attention-deficit hyperactivity disorder (ADHD) has not been examined. The aim of this study was to determine whether phthalate metabolites in urine are associated with poor neuropsychological performance in children with ADHD, and whether such association is affected by genotype-phthalate interaction. A cross-sectional examination of urine phthalate metabolite concentrations and the continuous performance test (CPT) were performed in 179 Korean children with ADHD recruited from department of psychiatry of university hospital. Correlations between urine phthalate metabolite concentrations and the CPT scores were investigated, and the interaction of phthalate metabolite levels with the selected polymorphisms at major candidate genes for ADHD, namely dopamine receptor D4 (DRD4), dopamine transporter, α-2A-adrenergic receptor, and norepinephrine transporter genes. For the subjects with the DRD4 4/4 genotype, there were significant associations of the urine phthalate metabolite concentrations with the number of omission errors, the number of commission errors, and the response time variability scores on the CPT. However, for the subjects without the DRD4 4/4 genotype, no significant associations were found. The results of this study suggest a possible association between phthalate metabolite concentrations and poor attentional performances of ADHD as well as a genetic influence on this association. Further prospective and epigenetic studies are needed to investigate causality and pathophysiological mechanisms.