Normative data and psychometric properties of the Patient Health Questionnaire-9 in a nationally representative Korean population.

BACKGROUND: The Patient Health Questionnaire-9 (PHQ-9) has been standardized in several populations and is widely used in clinical practice and health care. However, it has not been appropriately standardized in the Korean general population, and no normative data have been presented. The aim of this study was to provide the normative data and psychometric properties of the PHQ-9 in the nationally representative population of Korea. METHODS: We used the nationwide cross-sectional survey data of Korea from 2014 to 2016. The data of 10,759 individuals aged over 19 years were analyzed in this study. As the distribution of the PHQ-9 scores was not normative, the percentile ranks for raw scores were provided. The survey questionnaires included the PHQ-9, The EuroQol-5 Dimension (EQ-5D), and demographic characteristics. We analyzed the construct validity and internal consistency of the PHQ-9. RESULTS: The normative data of the PHQ-9 were generated according to the sex and different age categories. The correlation coefficient between the sum of the PHQ-9 scores and the EQ-5D index was 0.44, which was moderate. The most appropriate model was the two-factor model with five 'affective-somatic' labeled items and four 'cognitive' labeled items. Cronbach's α for the PHQ-9 was 0.79. CONCLUSIONS: Our result supports reliability and validity with two-factor structure of PHQ-9 for measuring depression in the Korean nationally representative population. The Korean normative data on the PHQ-9 according to percentile rank can assist in interpreting and comparing scores with other populations.

Role of Inflammation in Psychiatric Disorders.

Psychiatric disorders are too multifactorial to be defined as a primarily inflammatory disorder, and increased inflammatory response is not specific to mental disorder only. Numerous factors are involved in neuroinflammation, and there also are many confounding variables, making it difficult to obtain consistent outcomes. Therefore, it is necessary to specify genetic, physiological, and epidemiological attributes of particular population groups vulnerable to inflammatory response as well as the disease subtypes. As of now, definitive inflammatory markers for psychiatric disorders have not been identified, but they could be very useful in patients with minimal vulnerability. In addition, it is possible to use inflammatory markers as depression biomarkers in subtypes of depression, which can serve as bases to develop medications to treat the disorder.

Local gyrification index in patients with major depressive disorder and its association with tryptophan hydroxylase-2 (TPH2) polymorphism.

The tryptophan hydroxylase-2 (TPH2) gene is considered a promising genetic candidate regarding its association with a predisposition to major depressive disorder (MDD). Local gyrification reflects the early neural development of cortical connectivity, and is regarded as a potential neural endophenotype in psychiatric disorders. They aimed to investigate the alterations in the cortical gyrification of the prefrontal cortex and anterior cingulate cortex and their association with the TPH2 rs4570625 polymorphism in patients with MDD. One hundred and thirteen patients with MDD and eighty-six healthy controls underwent T1-weighted structural magnetic resonance imaging and genotyping for TPH2 rs4570625. The local gyrification index of 22 cortical regions in the prefrontal cortex and anterior cingulate cortex was analyzed using the FreeSurfer. The patients with MDD showed significant hypergyria in the right rostral anterior cingulate cortex (P = 0.001), medial orbitofrontal cortex (P = 0.003), and frontal pole (P = 0.001). There was a significant genotype-by-diagnosis interaction for the local gyrification index in the right rostral anterior cingulate cortex (P = 0.003). Their study revealed significant hypergyria of the anterior cingulate cortex and prefrontal cortex and an interactive effect between the diagnosis of MDD and the genotype in the anterior cingulate cortex. This might be associated with the dysfunction of neural circuits mediating emotion processing, which could contribute to pathophysiology of MDD. Hum Brain Mapp 38:1299-1310, 2017. © 2016 Wiley Periodicals, Inc.

Do Somatic Symptoms Predict the Severity of Depression? A Validation Study of the Korean Version of the Depression and Somatic Symptoms Scale.

This study aimed at exploring the psychometric characteristics of the Korean Version of the Depression and Somatic Symptoms Scale (DSSS) in a clinical sample, and investigating the impact of somatic symptoms on the severity of depression. Participants were 203 consecutive outpatients with current major depressive disorders (MDD) or lifetime diagnosis of MDD. The DSSS was compared with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the 17-items Hamilton Depression Rating Scale (HAMD). The DSSS showed a two-factor structure that accounted for 56.8% of the variance, as well as excellent internal consistency (Cronbach's alpha = 0.95), concurrent validity (r = 0.44-0.82), and temporal stability (intraclass correlation coefficient = 0.79). The DSSS had a high ability to identify patients in non-remission (area under receiver operating characteristic [ROC] curve = 0.887). Maximal discrimination between remission and non-full remission was obtained at a cut-off score of 22 (sensitivity = 82.1%, specificity = 81.4%). The number of somatic symptoms (the range of somatic symptoms) and the scores on the somatic subscale (SS, the severity of somatic symptoms) in non-remission patients were greater than those in remission patients. The number of somatic symptoms (slope = 0.148) and the SS score (slope = 0.472) were confirmed as excellent predictors of the depression severity as indicated by the MADRS scores. The findings indicate that the DSSS is a useful tool for simultaneously, rapidly, and accurately measuring depression and somatic symptoms in clinical practice settings and in consultation fields.

Gaba transporter SLC6A11 gene polymorphism associated with tardive dyskinesia.

BACKGROUND: Gamma-aminobutyric acid (GABA) insufficiency has been reported to be related to the tardive dyskinesia (TD) susceptibility. Inada et al. (Pharmacogenet Genomics 2008;18:317-23) identified eight genes belonging to GABA receptor signaling pathway that may be involved in TD susceptibility by genome-wide screening and they replicated associations in an independent sample for polymorphisms in SLC6A11 (GABA transporter 3), GABRG3 (c-3 subunit of GABA-A receptor) and GABRB2 (ß-2 subunit of GABA-A receptor). In this study, we tried to replicate their finding in a larger Korean sample and find if any of the genes was associated with the susceptibility to TD. METHODS: We selected three polymorphisms in SLC6A11 (rs4684742), GABRG3 (rs2061051) and GABRB2 (rs918528) from the previous study. We carried out a case-control study (105 TD and 175 non-TD schizophrenic patients) to identify the association between the three candidate polymorphisms and susceptibility to TD and their epistatic interactions by using the multifactor dimensionality reduction (MDR) algorithm. RESULTS: Among the three variants, SCL6A11 genotypes distribution showed a significant difference between the TD and non-TD patients (P = 0.049). However, GABRG3 and GABRB2 genotype distributions were not associated with TD (P = 0.268 and P = 0.976, respectively). Further, our analyses provided significant evidence for gene-gene interactions (SCL6A11, GABRG3 and GABRB2) in the development of TD. The odds ratio increased to 2.53 (CI = 1.515-4.217, P = 0.0003) when the genetic susceptibility to TD was analyzed with the three genes considered altogether through MDR approach. CONCLUSION: These results suggest that GABA receptor signaling pathway was associated with the increased susceptibility to TD in Korean schizophrenic patients.

Usefulness of the Patient Health Questionnaire-9 for Korean medical students.

OBJECTIVE: Depression may be highly prevalent among medical students, lowering their functioning and quality of life. Using appropriate extant depression scales to screen for depression and determining factors associated with depression can be helpful in managing it. This study examines the validity and reliability of the Patient Health Questionnaire-9 (PHQ-9) for medical students and the relationship between their scores and sociodemographic variables. METHODS: This study surveyed 174 medical students using demographic questionnaires, the PHQ-9, the Beck Depression Inventory (BDI), the Patient Heath Questionnaire-15 (PHQ-15), the Beck Anxiety Inventory (BAI), and the Perceived Stress Scale (PSS). It calculated the Cronbach's α for internal consistency and Pearson's correlation coefficients for test-retest reliability and convergent validity of the PHQ-9. In order to examine the relationship between depression and demographic variables, this study performed independent t tests, one-way analysis of variance, chi-square, and binary logistic regressions. RESULTS: The PHQ-9 was reliable (Cronbach's α = 0.837, test-retest reliability, r = 0.650) and valid (r = 0.509-0.807) when employed with medical students. Total scores on the PHQ-9 were significantly higher among low-perceived academic achievers than among high-perceived academic achievers (p < 0.01). Depression was more prevalent in poor-perceived academic achievers than in high-perceived academic achievers. Similarly, poor-perceived academic achievers were at greater risk of depression than were high-perceived academic achievers (odds ratio [95 % confidence interval] 3.686 [1.092-12.439], p < 0.05). CONCLUSIONS: The PHQ-9 has satisfactory reliability and validity in medical students in South Korea. Depression is related to poor-perceived academic achievement when measured with the PHQ-9. Early screening for depression with the PHQ-9 in medical students and providing prompt management to high scorers may not only be beneficial to students' mental health but also improve their academic performance.

Exploring Brainstem Structural Abnormalities: Potential Biomarkers for Panic Disorder.

Panic disorder (PD), characterized by recurrent and intense panic attacks, presents a complex interplay between psychological and neurobiological factors. Although the amygdala and hippocampus have been studied extensively in the context of PD, the brainstem's involvement remains relatively underexplored. This study aims to address this gap by examining structural abnormalities within specific brainstem regions, including the medulla, pons, and midbrain. The study sample population comprised twenty-one adult patients diagnosed with PD and an age-gender-education-matched control group. Utilizing rigorous inclusion and exclusion criteria, confounding factors related to comorbid psychiatric conditions and brain structure abnormalities were minimized. Our findings revealed a significant reduction in medulla volume among PD patients, a finding that persisted even after correcting for individual differences in total intracranial volume. The medulla's role in cardiovascular regulation and autonomic function, coupled with its involvement in fear responses, underscores its potential significance in the pathophysiology of PD. This study elucidates the medulla's structural abnormalities as a potential biomarker for PD. Understanding the role of the brainstem in PD could pave the way for more targeted and effective interventions for this condition.

Study on Awareness of Suicide and Suicide Prevention Among Community Youth.

Objectives: South Korea has the highest suicide rate among Organisation for Economic Co-operation and Development countries; there is an increasing trend in suicide attempts among middle and high school students. Various factors contribute to the risk of suicide among adolescents, and the perception of suicide prevention has emerged as a significant factor. This study aimed to investigate the association between emotional and behavioral difficulties among middle and high school students and their perceptions of suicide prevention and to explore differences in suicide perception according to age. Methods: A survey was conducted among community middle and high school students, including 530 participants, between 2020 and 2021. Emotional and behavioral difficulties were assessed using the Strengths and Difficulties Questionnaire-Korean version, and participants were asked to complete a questionnaire on the importance and possibility of suicide prevention. A correlation test and analysis of variance were used to examine the relationships between the variables, and suicide awareness was compared according to age. Results: The participants who displayed higher strength or lower difficulty were more likely to respond positively to suicide prevention measures. They also exhibited high strength and low difficulty levels, thus agreeing with the importance of suicide prevention. Regarding age-related perceptions of suicide, adults aged 20-29 years reported the lowest probability of suicide prevention. Conclusion: Suicide perceptions influence the incidence of suicide. Therefore, active societal engagement through suicide prevention campaigns and related education is essential to improve such perceptions. Continuous attention and support are required to address this issue.

Apnea-related sleep fragmentation and poor vigilance in children with well-controlled asthma.

It has been reported that sleep problems and neurocognitive deficit in asthmatic children is prevalent. However, systematic studies on these problems in stable asthma using polysomnography have rarely been performed. We therefore investigated sleep and neurocognitive functioning in children with well-controlled asthma. Forty-three children with well-controlled, stable asthma and 31 controls (age range: 6-9 years) were enrolled in the study. Subjects were questioned for daytime sleepiness using the Paediatric Daytime Sleepiness Scale. Complete overnight polysomnography and neurocognitive function tests were performed on all subjects. Children with stable asthma had lower pulmonary function in comparison to their age-matched controls. Asthmatic children had a higher apnea-hypopnea index (P < 0.001) and apnea-hypopnea-related arousal index (P < 0.001) as compared with non-asthmatics. Deep sleep was decreased in asthmatics (P = 0.001). In the vigilance test, the mean number of correct answers was lower (P = 0.005) and the mean reaction time was slower (P = 0.002) in asthmatic children. A hierarchical multiple linear regression showed that deep sleep and apnea-hypopnea-related arousal index were significant predictors of vigilance. The data suggest that the prevalence of paediatric sleep-disordered breathing and sleep fragmentation could be very high among children with well-controlled asthma. Moreover, vigilance, the ability to maintain attention and alertness, was worse in stable asthmatic children when compared with healthy controls. Sleep-disordered breathing should be checked even in stable asthmatic children as they are at risk for developing neurobehavioural deterioration associated with frequent arousals during sleep. Furthermore, early treatment for asthma may be required in order to prevent airway remodelling that could cause sleep problems.

Experiences and barriers to implementation of clinical practice guideline for depression in Korea.

BACKGROUND: Clinical guidelines can improve health-care delivery, but there are a number of challenges in adopting and implementing the current practice guidelines for depression. The aim of this study was to determine clinical experiences and perceived barriers to the implementation of these guidelines in psychiatric care. METHODS: A web-based survey was conducted with 386 psychiatric specialists to inquire about experiences and attitudes related to the depression guidelines and barriers influencing the use of the guidelines. Quantitative data were analyzed, and qualitative data were transcribed and coded manually. RESULTS: Almost three quarters of the psychiatrists (74.6%) were aware of the clinical guidelines for depression, and over half of participants (55.7%) had had clinical experiences with the guidelines in practice. The main reported advantages of the guidelines were that they helped in clinical decision making and provided informative resources for the patients and their caregivers. Despite this, some psychiatrists were making treatment decisions that were not in accordance with the depression guidelines. Lack of knowledge was the main obstacle to the implementation of guidelines assessed by the psychiatrists. Other complaints addressed difficulties in accessing the guidelines, lack of support for mental health services, and general attitudes toward guideline necessity. Overall, the responses suggested that adding a summary booklet, providing teaching sessions, and improving guidance delivery systems could be effective tools for increasing depression guideline usage. CONCLUSION: Individual barriers, such as lack of awareness and lack of familiarity, and external barriers, such as the supplying system, can affect whether physicians' implement the guidelines for the treatment of depression in Korea. These findings suggest that further medical education to disseminate guidelines contents could improve public health for depression.

There is no evidence for an association between the serotonin receptor 3A gene C178T polymorphism and tardive dyskinesia in Korean schizophrenia patients.

BACKGROUND: Tardive dyskinesia (TD) is a potential adverse effect of long-term treatment with antipsychotics. Previous studies have suggested a link between brain serotonergic systems and TD vulnerability. A recent report described that a serotonin 3 receptor (5-HTR3) agonist induced rhythmic movements in mice with complete paraplegia. Furthermore, it has been reported that the 5-HTR3 antagonist ondansetron is efficacious in the treatment of Gilles de la Tourette syndrome (GTS). AIM: The aim of the present study was to determine whether the 5-HTR3A gene C178T polymorphism is associated with antipsychotic-induced TD in Korean schizophrenia patients. METHODS: We investigated 280 Korean schizophrenia patients. Subjects with TD (n = 105) and without TD (n = 175) were matched for antipsychotic drug exposure and other relevant variables. RESULTS: The distributions of genotypic (chi-squared = 3.55, p = 0.169) and allelic (chi-squared = 0.40, p = 0.528) frequencies did not differ between patients with and without TD. The total score on the Abnormal Involuntary Movement Scale also did not differ between the two genotype groups (F = 0.94, p = 0.391). CONCLUSIONS: The findings of the present study do not support the involvement of the 5-HTR3A gene C178T polymorphism in TD in Korean schizophrenia subjects.

Plasminogen Activator Inhibitor-1: Potential Inflammatory Marker in Late-life Depression.

Objective: Although several previous studies have examined the association between late-life depression and blood adipokine levels, a marker of chronic inflammation, no studies have comprehensively considered the effects of metabolic syndrome, which is known to affect blood adipokine levels. This study examined blood adipokine levels in geriatric depression after adjusting for the effects of metabolic syndrome. Methods: Participants were selected from the Ansan Geriatric Study (depression group [n = 76] and control group [n = 76]). Blood concentrations of four adipokines (adiponectin, resistin, neutrophil-gelatinase-associated lipocalin [NGAL], and plasminogen activator inhibitor-1 [PAI-1]) were measured using immunoassays. The effects of blood adipokine concentration on the diagnosis of depression were analyzed using multivariate logistic regression to adjust for the effects of metabolic syndrome and potential confounding factors. Results: When the effects of metabolic syndrome and potential confounding factors were adjusted, only PAI-1 could explain the diagnosis of depression among all the adipokines. The depression group showed a lower blood PAI-1 level than the control group. Adiponectin, resistin, and NGAL could not explain the diagnosis of depression when the effects of metabolic syndrome and potential confounding factors were adjusted. Conclusion: This study suggests the possibility that the blood PAI-1 levels in clinically pathological late-life depression may show contrasting results to those with subclinical depressive symptoms. Additionally, considering that most previous studies have been conducted with pre-geriatric populations, the study suggests the possibility that geriatric depression may show inflammatory changes with patterns that are different from those of depression in the pre-geriatric population.

Hyperprolactinemia induced by low-dosage amisulpride in Korean psychiatric patients.

AIM: Amisulpride at low dosages enhances dopaminergic neurotransmission by preferentially blocking presynaptic D2/D3 receptors. Thus, low dosages of amisulpride are expected not to increase prolactin levels. The aim of this study was to examine whether low dosages of amisulpride can increase serum levels of prolactin or not clinically in Korean patients. METHOD: Serum prolactin levels were measured in 20 Korean patients (12 men and eight women) with various diagnoses who were treated with less than 300 mg of amisulpride per day. RESULTS: The mean dosage of amisulpride was 195.0 ± 51.0 mg/day, and serum level of prolactin was 76.1 ± 43.4 ng/mL. The prolactin level was significantly higher in women (110.7 ± 49.3 ng/mL) than in men (53.1 ± 15.9 ng/mL) after administering amisulpride (P = 0.021), while the dosage of amisulpride did not differ significantly between men (200.0 ± 42.6 mg/day) and women (187.5 ± 64.1 mg/day) (P = 0.576). CONCLUSIONS: The low dosages of amisulpride elevate serum prolactin level in the majority of patients. This finding indicates that the dose-reduction of amisulpride has little effect to relieve amisulpride-induced hyperprolactinemia at therapeutic dosages. Clinicians should monitor serum prolactin level even when low dosages of amisulpride are administered.

The T allele of the interferon-gamma +874A/T polymorphism is associated with bipolar disorder.

BACKGROUND: Previous studies have shown that patients with bipolar disorder (BD) tend to have altered immune system function. Several studies have reported that changes in interferon-gamma (IFN-γ) may play an important role in the development of BD. AIMS: To investigate the relationship between IFN-γ and BD, 156 patients with BD and 175 control subjects were genotyped for the IFN-γ +874A/T single nucleotide polymorphism. RESULTS: We detected significant differences in the genotype distributions and allele frequencies of the IFN-γ +874A/T single nucleotide polymorphism (rs2430561) between patients with BD and normal controls. The T allele was found to be significantly more common among patients with BD than in controls. Additionally, significant differences in scores on the Young Mania Rating Scale (YMRS) were found between the three genotypes of this polymorphism. CONCLUSIONS: Our results suggest that the IFN-γ +874A/T polymorphism may have important effects related to susceptibility to BD and that the T allele may be associated with an increased risk of developing BD.

Role of cytokines in atypical depression.

BACKGROUND: Atypical depression (AD) is considered a biologically and psychologically distinct subtype of depression. AD, contrary to melancholic depression (MD), may have different alteration in cytokine activity. AIMS: We aimed to investigate the differences of cytokine activity between AD patients and MD patients. Among psychiatric patients visited to the Psychiatry Department, Korea University Medical Center, 105 patients with major depression who met the Diagnostic and Statistical Manual (DSM-IV) criteria based on clinical interviews using a Structured Clinical Interview for DSM-IV were recruited. Among 105 patients, 35 patients had atypical feature. We measured in vitro cytokines (interleukins) IL-2, IL-4, IL-6 and tumor necrosis factor-α (TNF-α). RESULTS: Decreased IL-4 and increased IL-2 was observed in AD patients. IL-6 and TNF-α level of AD patients showed no difference from the controls. CONCLUSIONS: Contrary to MD, AD has reversed vegetative symptoms, i.e. hypersomnia and hyperphagia. It is assumed that the phenotype difference between AD and MD might be related to Th1 cytokines (IL-2) and Th2 cytokines (IL-4) and not related to monocytic cytokines (IL-6, and TNF-α).

Feeling Blue and Getting Red: An Exploratory Study on the Effect of Color in the Processing of Emotion Information.

Specific emotions and colors are associated. The current study tested whether the interference of colors with affective processing occurs solely in the semantic stage or extends to a more complex stage like the lexical processing of emotional words. We performed two experiments to determine the effect of colors on affective processing. In Experiment 1, participants completed a color-emotion priming task. The priming stimulus included a color-tinted (blue, red, and gray) image of a neutral face, followed by a target stimulus of gray-scaled emotional (angry and sad) and neutral faces after 50 ms. Experiment 2 used a modified emostroop paradigm and superimposed emotion words on the center of the color-tinted emotional and neutral faces. Results showed the priming effect of red for the angry face compared to the control, but not in blue for the sad face compared to the control. However, responses to the blue-sad pair were significantly faster than the red-sad pair. In the color-emostroop task, we observed a significant interaction between color and emotion target words in the modified emostroop task. Participants detected sad targets more accurately and faster in blue than red, but only in the incongruent condition. The results indicate that the influence of color in the processing of emotional information exists at the semantic level but found no evidence supporting the lexical level effect.

Suicide and Suicide Prevention Awareness in Korea During the COVID-19 Pandemic.

OBJECTIVE: Owing to prolonged social distancing and the resultant isolation, the prevalence of depression and suicidality has increased during the COVID-19 pandemic. This study aimed to investigate the severity of depression and suicidality in Korean community populations and examine their awareness of suicide and suicide prevention during the pandemic. METHODS: This study surveyed a community population in 2020 and 2021, involving 668 participants. We evaluated the severity of depression and suicidality using the Patient Health Questionnaire-9 and Beck Scale for Suicidal Ideation as well as questions about awareness of suicide. We performed a correlation analysis to confirm the association between variables, and compared participants' suicide awareness according to the severity of depression. RESULTS: The severity of depression and suicidality in the community population decreased in 2021 compared to 2020. Awareness of the importance of suicide prevention increased in 2021, but the percentage reporting that it is possible decreased slightly. The group with higher depressive symptoms reported a lower possibility of suicide prevention. CONCLUSION: Increasing social interest in suicide, as well as awareness of suicide prevention, is important for reducing suicide rates. Suicide prevention campaigns, education, and social policies are needed, particularly during the pandemic.

Impact of the COVID-19 Pandemic on Korean Adolescents' Mental Health and Lifestyle Factors.

PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic has caused changes in the daily lives of Korean adolescents and affected their emotional well-being. This study compared lifestyle factors and the mental health status of adolescents before and during the COVID-19 pandemic. METHODS: We conducted a secondary analysis using data from a national cross-sectional cohort (Korean Youth Risk Behavior Web-based Survey, KYRBS) collected in 2019 before the COVID-19 outbreak and in 2020 during the pandemic. This study included 57,303 students from the 2019 KYRBS and 54,948 from the 2020 KYRBS. Lifestyle factors such as dietary habits, physical activity levels, time spent studying, duration of Internet use, and mental health status, including perceived stress, experience of depressive mood, and suicidal ideation and attempts, were included in the analyses. RESULTS: The perceived stress levels, self-reported depressive mood, and suicidal thoughts and attempts were lower in the students surveyed in 2020 during the COVID-19 pandemic than in the students surveyed in 2019 before the COVID-19 outbreak. The time spent studying and sleep duration decreased compared to before the pandemic, and sleep satisfaction increased during the COVID-19 pandemic. DISCUSSION: Our results showed an improvement in mental health status in Korean adolescents during the pandemic, but caution is needed when interpreting these results. Future research is needed to determine the effects of a long-lasting pandemic on mental health and lifestyle factors in adolescents.

Validation of the Korean version of the Generalized Anxiety Disorder 7 self-rating Scale.

This study examined the validity and reliability of the Korean version of the Generalized Anxiety Disorder-7 (GAD-7) scale. The GAD-7 was standardized with data from 112 patients at a psychiatric outpatient clinic. The GAD-7 revealed high internal consistency, good test-retest reliability, and convergent validity. The ROC analysis resulted in poor sensitivity and specificity for detecting anxiety disorders in a psychiatric setting. The GAD-7 may not be useful in diagnosing anxiety disorders in a psychiatric setting, even though it appears to be a reliable, efficient, and valid measurement tool for evaluating anxiety symptoms.

Effect of serotonin-related gene polymorphisms on pathogenesis and treatment response in Korean schizophrenic patients.

Serotonin has been implicated in the pathophysiology of several psychiatric disorders including schizophrenia. Serotonergic system-related genes may be good candidates in investigating the genetic basis of schizophrenia. We aimed to investigate the associations of HTR1A C-1019G, HTR2A-1438A/G, TPH1 218A/C, and TPH2-703G/T variants with schizophrenia. A total of 202 patients with schizophrenia and 165 normal controls were genotyped for HTR1A C-1019G, HTR2A-1438A/G, TPH1 218A/C, and TPH2-703G/T single nucleotide polymorphisms (SNPs). In order to assess the severity of a patient's psychiatric symptoms, the brief psychiatric rating scale (BPRS), the positive and negative symptom scale (PANSS), and the Calgary depression scale for Schizophrenia (CDSS) were administered. Genotype and allele frequencies were compared between groups via χ(2) statistics. Associations between the genotypes of candidate SNPs with the severity of symptoms were examined with ANOVA by comparing the mean scores of BPRS, PANSS, and CDSS according to genotype. No significant differences in the genotype distributions and allele frequencies of four SNPs were found between patients with schizophrenia and normal controls. There was a trend towards association of HTR1A C-1019G polymorphism with negative symptom. Negative symptom score of PANSS was lower in the patients with CC genotype than in the G allele carriers. These results suggested that C allele might be associated with lesser negative symptom. More studies are needed to confirm these findings. In the future, we plan to study the associations between schizophrenia and other genetic polymorphisms.