The cost-of-illness trend of schizophrenia in South Korea from 2006 to 2016.

Globally, about one in four people develop a psychiatric disorder during their lifetime. Specifically, the lifetime prevalence of schizophrenia is about 0.48%, and schizophrenia can have detrimental effects on a patient's life. Therefore, estimating the economic burden of schizophrenia is important. We investigated the cost-of-illness trend of schizophrenia in South Korea from 2006 to 2016. The cost-of-illness trend was estimated from a societal perspective using a prevalence-based approach for direct costs and a human capital approach for indirect costs. We utilized information from the following sources: 1) National Health Insurance Service, 2) Korean Statistical Information Service, Statistics Korea, 3) the National Survey of Persons with Disabilities, 4) Budget and Fund Operation Plan, Ministry of Justice, 5) Budget and Fund Operation Plan, Ministry of Health and Welfare, and 6) annual reports from the National Mental Health Welfare Commission. Direct healthcare costs, direct non-healthcare costs, and indirect costs by sex and age group were calculated along with sensitivity analyses of the estimates. The cost-of-illness of schizophrenia in Korea steadily increased from 2006 to 2016, with most costs being indirect costs. Individuals in their 40s and 50s accounted for most of the direct and indirect costs. Among indirect costs, the costs due to unemployment were most prevalent. Our estimation implies that schizophrenia is associated with a vast cost-of-illness in Korea. Policymakers, researchers, and physicians need to put effort into shortening the duration of untreated psychosis, guide patients to receive community-care-based services rather than hospital-based services and empower lay people to learn about schizophrenia.

Common gray and white matter abnormalities in schizophrenia and bipolar disorder.

This study aimed to investigate abnormalities in the gray matter and white matter (GM and WM, respectively) that are shared between schizophrenia (SZ) and bipolar disorder (BD). We used 3T-magnetic resonance imaging to examine patients with SZ, BD, or healthy control (HC) subjects (aged 20-50 years, N = 65 in each group). We generated modulated GM maps through voxel-based morphometry (VBM) for T1-weighted images and skeletonized fractional anisotropy, mean diffusion, and radial diffusivity maps through tract-based special statistics (TBSS) methods for diffusion tensor imaging (DTI) data. These data were analyzed using a generalized linear model with pairwise comparisons between groups with a family-wise error corrected P < 0.017. The VBM analysis revealed widespread decreases in GM volume in SZ compared to HC, but patients with BD showed GM volume deficits limited to the right thalamus and left insular lobe. The TBSS analysis showed alterations of DTI parameters in widespread WM tracts both in SZ and BD patients compared to HC. The two disorders had WM alterations in the corpus callosum, superior longitudinal fasciculus, internal capsule, external capsule, posterior thalamic radiation, and fornix. However, we observed no differences in GM volume or WM integrity between SZ and BD. The study results suggest that GM volume deficits in the thalamus and insular lobe along with widespread disruptions of WM integrity might be the common neural mechanisms underlying the pathologies of SZ and BD.

Health Behaviors, Physical Health, and Health Care Utilization in Children With ADHD.

Objective: To compare health behaviors, physical health outcomes, and health care utilization between children with and without ADHD. Method: In this cross-sectional study, we obtained data for children with and without ADHD from the Korean National Health and Nutrition Examination Survey. To investigate the association between ADHD and health outcomes, we estimated the adjusted prevalence ratios (APRs) in these groups. Results: Among 10,838 children aged 7 to 18 years with and without ADHD, those with ADHD had significantly higher APRs for overall health problems, physical illness, and injuries than those without ADHD. Despite having health care needs, children with ADHD were less likely than those without ADHD to use health care services. However, there were no significant associations between most health behaviors and ADHD. Conclusion: Increased efforts are needed to provide quality health care services to address the medical conditions of children with ADHD and to enhance their health care utilization when needed.

Detection of Suicide Attempters among Suicide Ideators Using Machine Learning.

OBJECTIVE: We aimed to develop predictive models to identify suicide attempters among individuals with suicide ideation using a machine learning algorithm. METHODS: Among 35,116 individuals aged over 19 years from the Korea National Health & Nutrition Examination Survey, we selected 5,773 subjects who reported experiencing suicide ideation and had answered a survey question about suicide attempts. Then, we performed resampling with the Synthetic Minority Over-sampling TEchnique (SMOTE) to obtain data corresponding to 1,324 suicide attempters and 1,330 non-suicide attempters. We randomly assigned the samples to a training set (n=1,858) and a test set (n=796). In the training set, random forest models were trained with features selected through recursive feature elimination with 10-fold cross validation. Subsequently, the fitted model was used to predict suicide attempters in the test set. RESULTS: In the test set, the prediction model achieved very good performance [area under receiver operating characteristic curve (AUC)=0.947] with an accuracy of 88.9%. CONCLUSION: Our results suggest that a machine learning approach can enable the prediction of individuals at high risk of suicide through the integrated analysis of various suicide risk factors.

Long-term Effects of Aripiprazole Treatment during Adolescence on Cognitive Function and Dopamine D2 Receptor Expression in Neurodevelopmentally Normal Rats.

OBJECTIVE: This study aimed to investigate the long-term effects of aripiprazole treatment during adolescence on behavior, cognitive function, and dopamine D2 receptor (D2R) expression in adult rats. METHODS: Adolescent male Sprague-Dawley rats were injected intraperitoneally with aripiprazole, risperidone, or vehicle control for 3 weeks (postnatal day 36‒56). After a 2-week washout period, locomotion, anxiety, and spatial working memory were evaluated in adulthood (postnatal day 71‒84), using an open field test, elevated plus maze, and Y-maze, respectively. In addition, we assessed D2R levels in the dorsolateral and medial prefrontal cortex (PFC), dorsal and ventral striatum, and hippocampus using western blot analysis. RESULTS: Spontaneous alternation performance (SAP) in the Y-maze, a measure of spatial working memory, differed significantly among the 3 groups (F = 3.89, p = 0.033). A post-hoc test confirmed that SAP in the aripiprazole group was significantly higher than that in the risperidone group ( post-hoc test p = 0.013). D2R levels in the medial PFC (F= 8.72, p= 0.001) and hippocampus (F= 13.54, p > 0.001) were different among the 3 groups. D2R levels in the medial PFC and hippocampus were significantly lower in the aripiprazole-treated rats than that in the risperidone-treated rats (post-hoc test p = 0.025 and p > 0.001, respectively) and controls (post-hoc test p > 0.001, all). CONCLUSION: This study showed that aripiprazole treatment in adolescence could influence cognitive function and dopaminergic neurotransmission into early adulthood.

Mental Health Literacy of Autism Spectrum Disorder in Korea: Recognition, Etiology, Treatment.

OBJECTIVE: The objective of this study was to investigate the Korean public's recognition of autism spectrum disorder (ASD), revealing underlying factors regarding perception relative to etiology and treatment of ASD, and examining variables related to those factors. METHODS: An online survey was held to investigate mental health literacy (MHL) on ASD of the general public in Korea. A total of 673 adults participated and completed questionnaires on socio-demographic characteristics and if they know someone with ASD. Next, participants were provided with a vignette describing a child with ASD. Only those that recognized there was a problem with the child moved to the next part which asked their perception regarding etiology and treatment of ASD. RESULTS: According to our study, approximately 25% of participants correctly recognized the child in the vignette as having ASD. Perception regarding etiology and treatment of ASD varied among socio-demographic characteristics. Participants acquainted with someone with ASD and correctly recognized ASD held mixed perception regarding cause and treatment. CONCLUSION: This study investigated MHL of ASD in Korea. The result reveals there is much room for improvement relative to raising awareness on MHL of ASD. Intervention considering socio-demographic characteristics and acquaintance with ASD are needed.

Default mode network connectivity is associated with long-term clinical outcome in patients with schizophrenia.

This study investigated whether resting-state functional connectivity is associated with long-term clinical outcomes of patients with schizophrenia. Resting-state brain images were obtained from 79 outpatients with schizophrenia and 30 healthy controls (HC), using a 3 T-MRI scanner. All patients were 20-50 years old with >3 years' duration of illness and appeared clinically stable. We assessed their psychopathology using the 18-item Brief Psychiatric Rating Scale (BPRS-18) and divided them into "good," "moderate," and "poor" outcome (SZ-GO, SZ-MO, and SZ-PO) groups depending on BPRS-18 total score. We obtained individual functional connectivity maps between a seed region of the bilateral posterior cingulate cortex (PCC) and all other brain regions and compared the functional connectivity of the default mode network (DMN) among the HC and 3 schizophrenia outcome groups, with a voxel-wise threshold of P < .001 within a cluster-extent threshold of 114 voxels. Additionally, we assessed correlations between functional connectivity and BPRS-18 scores. The SZ-MO and SZ-PO groups showed decreased functional connectivity between PCC and right ventromedial prefrontal cortex (vmPFC), left middle cingulate cortex, and left frontopolar cortex (FPC) compared to the SZ-GO and HC groups. DMN connectivity in the right vmPFC and left FPC negatively correlated with subscale scores of the BPRS-18, except the negative symptoms subscale. In this study, poorer clinical outcomes in patients with schizophrenia were associated with decreased DMN connectivity. In particular, the decreased functional connectivity might be related to the severity of positive and mood symptoms rather than negative symptoms.

Comorbidity of Alcohol Use and Other Psychiatric Disorders and Suicide Mortality: Data from the South Korean National Health Insurance Cohort, 2002 to 2013.

BACKGROUND: Previous studies have indicated that alcohol use disorder (AUD) and other psychiatric disorders increase the risk of suicide mortality. However, little research has investigated the concomitant effect of comorbid psychiatric disorders on suicide mortality. This study aimed to investigate the effect of comorbid AUD on suicide mortality of individuals with another psychiatric disorder using a national data sample. METHODS: We used the National Health Insurance Service-National Sample Cohort data from 2002 to 2013. We selected individuals with specific psychiatric disorders based on the International Classification of Diseases, 10th revision (F10-F48). Overall, the study included 741,601 participants. We utilized a prioritization process to identify the primary diagnosis for those with multiple diagnoses. All-cause mortality rates and suicide rates per 100,000 person-year (days) and the standardized mortality ratio (SMR) were calculated. Then, we compared the suicide-specific SMR of 3 different groups: (i) specific psychiatric disorder versus general public; (ii) specific psychiatric disorder comorbid with AUD versus general public; and (iii) specific psychiatric disorder comorbid with AUD versus specific psychiatric disorder without comorbid AUD. RESULTS: Patients with any specific psychiatric disorder showed higher suicide-specific SMR compared to the general population. Being comorbid with AUD further increased the risk of suicide among psychiatric patients. In particular, patients with bipolar affective disorders, organic mental disorders, or depressive disorders comorbid with AUD had about 2 to 4 times higher suicide-specific SMR compared to those without AUD (bipolar affective disorder: SMR = 3.01, 95% confidence interval (CI) [1.49, 4.54]; organic mental disorder: SMR = 3.43, 95% CI [1.05, 5.81]; depressive disorder: SMR = 2.06, 95% CI [1.52, 2.61]). CONCLUSIONS: Our data indicate that having a psychiatric disorder increases the risk of committing suicide. More importantly, comorbid AUD further increases this risk of suicidal death for certain psychiatric disorders. This shows the importance of determining whether patients with psychiatric disorders have comorbid AUD to prevent suicide.

Effect of comorbid depression on health-related quality of life of patients with chronic diseases: A South Korean nationwide study (2007-2015).

OBJECTIVE: Patients with chronic physical diseases often have concomitant depression. Depression influences an individual's health and his or her overall health-related quality of life (HRQoL). The extent to which depression incrementally worsens HRQoL in patients with ≥1 comorbid physical chronic diseases remains unclear. METHODS: This cross-sectional study is based on data of 50,844 respondents (age, ≥19 years) who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) (2007-2015). HRQoL was measured using the modified EuroQol five-dimensional (EQ-5D) score. Mean HRQoL scores were compared between subgroups of respondents with or without depression. The association between HRQoL and disease status was evaluated using multiple regression models after controlling for sociodemographic variables. RESULTS: HRQoL score decreased when depression was concomitant. HRQoL score of respondents who had ≥3 chronic diseases with concomitant depression (mean = 0.83, SE = 0.010) were significantly lower (p = 0.002) than those of respondents who had ≥3 chronic diseases but no concomitant depression (mean = 0.87, SE = 0.007). Moreover, respondents with ≥3 chronic diseases comorbid with depression showed the largest negative association (coefficient = -0.133, p < 0.001) with HRQoL among all disease status groups. CONCLUSION: Presence of depression incrementally worsened individual's HRQoL when comorbid with other physical diseases. Especially, depression showed substantial negative effect on HRQoL level in patients with ≥2 physical diseases.

A Preliminary Study to Determine Comprehensive Research and Development Plans for Promoting Mental Health Services.

OBJECTIVES: The aim of this study was to analyze research and development projects in mental health services in Korea, using priority evaluation of mental health promotion policies to determine direction of the service. METHODS: An online survey was conducted that targeted experts in the mental health service regarding promotion of mental health in Korea in 2016. The survey was based on 32 policy projects that resulted from 12 strategies according to 4 policy objectives. RESULTS: Analysis of 32 mental health projects were assessed regarding the possibility of technology development success, magnitude of the ripple effect, and necessity of a national response. It was observed that 3 policy projects relevant to suicide, had a high relative priority. This was followed by policies for improvement of health insurance and the medical benefit cost system, and policies for reinforcement of crisis psychological support such as those for disaster victims. CONCLUSION: The prioritization of mental health services should place an emphasis on promotion of a healthy mental lifestyle, rehabilitation support for patients with serious mental illness, and reinforcement of social safety networks for suicide prevention.

Public recognition of attention-deficit hyperactivity disorder in Korea: Correct identification, causes, treatments, and social distance.

INTRODUCTION: To examine the Korean public's recognition of attention deficit hyperactivity disorder (ADHD), its sociodemographic correlates, and its implications for lay beliefs and social attitudes. METHODS: Six hundred seventy-three Korean adults were recruited for an online survey. Participants completed questionnaires on sociodemographic characteristics and their familiarity with ADHD. Participants were then provided with a vignette describing a person with ADHD symptoms, and subsequently were asked to answer whether the person had any sort of problem. Among the 673 participants who were initially recruited, those who recognized any problem responded to subsequent questions concerning the exact identification of the disorder, their beliefs about its etiology and treatment, and their preferences for social distance. RESULTS: It was found that 30.8% of participants perceived no problem and that 23.9% of those who did recognize a problem correctly identified ADHD as the diagnosis. Female gender, younger age, higher family income, higher education level, and having had any acquaintance with ADHD were associated with the correct identification of ADHD. The correct identification of ADHD was positively associated with behavioral/discipline beliefs and decreased social distance toward persons with ADHD, whereas it was negatively associated with beliefs concerning diet and personal characteristics. DISCUSSION: The present study highlights the importance of the accurate recognition of ADHD in relation to appropriate beliefs about its etiology, treatment strategies, and better social attitudes toward persons with ADHD.

Korean adults' beliefs about and social distance toward attention-deficit hyperactivity disorder, Tourette syndrome, and autism spectrum disorder.

Given the scarcity of studies examining public beliefs regarding multiple neurodevelopmental disorders, this study compared lay beliefs regarding the etiology of attention-deficit hyperactivity disorder (ADHD), Tourette syndrome (TS), and autism spectrum disorder (ASD), and attitudes toward individuals with the disorders. We recruited 673 participants aged 20-64 years via an online panel survey in South Korea. Participants completed questionnaires regarding perceived causation of each disorder. Preferred social distance from people with the disorders was measured using a modified version of the Bogardus Social Distance Scale. Four causal factors were revealed: dietary/physical, social-environmental, biological, and volitive/religious. ADHD causes were considered more social-environmental relative to TS and ASD causes, while ASD causes were considered more dietary/physical and biological relative to ADHD and TS causes. Preferred social distances for ASD and TS were the highest and lowest, respectively. Greater social distance from individuals with ADHD and TS was associated with older age; having close family members, relatives, or friends with the disorder; and beliefs regarding biological etiology. Greater social distance from individuals with ASD was associated with beliefs regarding biological etiology. Beliefs regarding ADHD, TS, and ASD causes and attitudes toward the disorders differed, and beliefs regarding etiology affected preferred social distance.

Changes in antipsychotic drug usage and factors affecting the use of typical drugs based on nationwide health insurance data in South Korea.

OBJECTIVES: To determine changes in antipsychotic drug usage in all South Korean patients with schizophrenia in 2011-2015 and factors affecting their utilisation in 2015. DESIGN AND SETTING: Retrospective cohort study using health insurance claims data on patients with schizophrenia in South Korea in 2011-2015. PARTICIPANTS: All treated patients with schizophrenia in South Korea in 2011-2015. The number of patients with schizophrenia was 171 302 in 2011, 175 488 in 2012, 177 763 in 2013, 180 079 in 2014 and 183 427 in 2015. MAIN OUTCOME MEASURES: Changes in antipsychotic drug usage and factors affecting the use of antipsychotics. RESULTS: Among patients with schizophrenia, there were tendencies of decreased use of antipsychotic combination therapy of typical drugs (from 11.5% to 7.5%) but increased use of combination therapy of atypical drugs (from 21.8% to 29.0%). Factors affecting the use of typical drugs were sex, age, geographical region, type of benefits/insurances and type of medical institutions. Use of typical antipsychotics was increased by age (OR=1.02, 95% CI 1.02 to 1.02). It was higher in men (OR=1.27, 95% CI 1.23 to 1.30) than that in women. It was higher in Medicaid benefiters (OR=4.49, 95% CI 4.35 to 4.64) than that in patients with health insurance. Use of typical drugs was higher among patients treated in general hospitals (OR=1.46, 95% CI 1.32 to 1.64), primary hospitals (OR=3.25, 95% CI 2.95 to 3.59), long-term care hospitals (OR=3.00, 95% CI 2.59 to 3.49) and clinics (OR=8.87, 95% CI 8.06 to 9.76) compared with that in tertiary care hospitals. Compared with metropolitan region, higher use of typical antipsychotics was seen in Gangwon (OR=1.14, 95% CI 1.05 to 1.25), Jeolla (OR=1.32, 95% CI 1.26 to 1.39) and Gyeongsang (OR=1.14, 95% CI 1.10 to 1.18) provinces. CONCLUSIONS: Results of this study confirmed changes of antipsychotic drug usage from typical to atypical antipsychotics in the treatment of schizophrenia and identified factors affecting the use of typical drugs, in contrast with current treatment trend in South Korea. These results may be used in the improvement of a medical system.

Physical Activity of Patients with Chronic Schizophrenia and Related Clinical Factors.

OBJECTIVE: This study aimed to investigate clinical factors contributing to the low physical activity (PA) of patients with chronic schizophrenia. METHODS: PA was measured in 50 outpatients with chronic schizophrenia using the International Physical Activity Questionnaire Short Form (IPAQ-SF). Psychopathology, psychosocial functioning, and extrapyramidal symptoms were assessed using the 18 item-Brief Psychiatric Rating Scale (BPRS-18), Global Assessment of Functioning (GAF), and Drug-Induced Extrapyramidal Symptom Scale (DIEPSS), respectively. We examined differences in these clinical variables between "inactive," "minimally active," and "health enhancing physical activity" groups. Linear regression analysis was used to examine the clinical factors explaining low PA levels in patients with schizophrenia. RESULTS: Subjects spent an average of 130.18±238.89 min/wk on moderate/vigorous-intensity PA and only 26% of them met the recommended PA guideline of 150 minutes of at least moderate PA per week. The inactive group showed significantly higher BPRS-18 and DIEPSS scores, and a lower GAF score than the other groups. Linear regression analysis showed that DIEPSS scores independently explained the amount of total PA (p=0.001) and time spent being sedentary (p=0.028). CONCLUSION: This study provides preliminary evidence that extrapyramidal symptoms could be a major impediment to the PA of patients with schizophrenia.

Correction to: Risk factors for relapse in patients with first-episode schizophrenia: analysis of the Health Insurance Review and Assessment Service data from 2011 to 2015.

[This corrects the article DOI: 10.1186/s13033-018-0187-1.].

The Prevalence of Chronic Physical Diseases Comorbid with Depression among Different Sex and Age Groups in South Korea: A Population-Based Study, 2007-2014.

OBJECTIVE: People with depression often suffer from comorbid, chronic physical diseases. Little is known about how demographic characteristics such as age and sex influence the prevalence of chronic physical diseases comorbid with depression. Therefore, this study aimed to explore the age and sex differences in the prevalence of diverse, chronic physical diseases comorbid with depression. METHODS: This cross-sectional survey were conducted with the participants (n=45,598) of the Korean National Health and Nutrition Examination Survey (KNHANES). Using log-binomial regression, age adjusted prevalence ratios (APR) of chronic physical diseases of participants with depression and those without depression were estimated for each sex and age group. RESULTS: The APR of most chronic physical diseases were significantly higher among respondents with depression than those without depression. Chronic physical diseases that showed the highest APR were asthma in adult male respondents (APR=3.46) and adult female respondents (APR=2.19) and chronic renal failure in elderly male respondents (APR=8.36) and elderly female respondents (APR=1.94). CONCLUSION: Prevalence ratios of the chronic physical diseases comorbid with depression differed according to sex and age groups. Collaborative care strategies should be designed according to demographic characteristics of the population.

Analysis of the Health Insurance Review and Assessment Service data from 2011 to 2015.

BACKGROUND: Schizophrenia is a recurrent, debilitating disease that is rarely curable. Rapid intervention after the first episode of schizophrenia has been shown to positively affect the prognosis. Unfortunately, basic data is scarce on first-episode schizophrenia in Korean patients making it difficult to create a comprehensive list of risk factors for relapse. This study aims to investigate the demographic characteristics and institutional factors of patients with first-episode schizophrenia in order to identify risk factors for relapse. METHODS: Data from the Health Insurance Review & Assessment Service (HIRA) was used for this study to represent the Korean patient population. To identify factors affecting relapse, we explored gender, age, geographic location, medical benefits, type of medical institution, type of medication used, medication adherence, and the severity of symptoms. Data analysis was performed using the Cox proportional hazard model. RESULTS: The number of patients diagnosed with first-episode schizophrenia in Korea over a 2-year period was 4567 of which 1265 (27.7%) patients experienced a relapse during the observational period. Factors affecting relapse included age, type of medical institution, type of medication used, medication adherence, and type of treatment (inpatient or outpatient) after the initial diagnosis, which varied depending upon the severity of symptoms. CONCLUSIONS: It was found that environmental and institutional factors as well as the type of medical treatment were crucial in determining whether patients with first-episode schizophrenia subsequently relapsed. The results of this study can be utilized as source material for directing therapeutic interventions and improving mental health policies in the future.

Influencing factors of attitudes toward seeking professional help for mental illness among Korean adults.

OBJECTIVES: Identifying predictors of psychological help-seeking attitudes is essential to improve access to needed mental health services. We investigated factors - particularly Big Five personality traits - that affect attitudes toward seeking professional psychological help for mental illness among Korean adults. METHODS: A total of 654 participants aged 15-54 years were recruited through an online panel survey. Help-seeking attitudes for mental illness were measured by the Attitudes Toward Seeking Professional Psychological Help Scale (ATSPPH), and personality traits were measured by the Big Five Personality Inventory-10. RESULTS: Multivariate analyses showed that female gender, history of psychiatric diagnosis, agreeableness and openness to experience were significantly associated with positive attitudes toward seeking professional psychological help for mental illness. CONCLUSIONS: These findings suggest that specific personality traits should be considered when developing strategies to promote positive attitudes toward seeking professional psychological help. Further research using a representative community sample is needed to generalize our findings.

The longitudinal trends in the relationship between drug-induced extrapyramidal symptoms and personal and social performance in a population of the patients with schizophrenia: A latent growth model.

The aim of this study was to explore the longitudinal trends in the relationship between personal and social functioning and drug-induced extrapyramidal symptoms (DIEPS). The baseline sample included 484 patients with schizophrenia. Participants were assessed at baseline, weeks 4 (time 2), 8 (time 3), and 12 (time 4) regarding social functioning, and DIEPS. In latent growth analysis, the path coefficient between the intercept for the DIEPSS and the intercept for the PSP indicated a significant cross-sectional relationship between these two variables. And the path coefficient between the intercept of the DIEPSS and the slope of the PSP was also significant, indicating that patients who initially had more serious side effects tended to exhibit less improvement in their personal and social functioning over time. Similarly, a significant path coefficient between the slopes of the two variables indicated a dynamic and possibly reciprocal association over time. In addition, K-PSP scale showed good construct validity and reliability. Based on the standardized PSP scale, our results demonstrate DIEPSS induced by antipsychotic treatment dynamically affect personal and social functioning over time, a negative association between psychosocial aspects and the DIEPS.

Longitudinal relationship between Personal and Social Performance (PSP) and anxiety symptoms in schizophrenia.

BACKGROUND: We aimed to examine the longitudinal relationship between the personal and social functioning and anxiety symptoms in patients with schizophrenia. For this purpose, we confirmed the validity of the anxiety subscale of the Symptom-Checklist-90-Revised (SCL-90-R) and then applied the latent growth modeling method for longitudinal causal relationships. METHODS: Five hundred and seventy-eight patients diagnosed with schizophrenia were evaluated and 369 patients were included in the study at baseline. After conducting Rasch model analyses for the validation of the anxiety subscale in the SCL-90-R, we applied latent growth model to determine the causal relationship between the PSP and the anxiety symptoms. RESULTS: The validity of the anxiety subscale of the SCL-90-R was confirmed based on the Rasch rating model, where the criteria for Infit, Outfit, item difficulty, and point-measure correlations were satisfied. The results from the latent growth model showed that the intercept and slope (rate of change) of the PSP negatively predicted the slope of anxiety symptoms along the longitudinal trajectory. Together with previous studies examining the predictive role of anxiety symptoms on quality of life, our longitudinal findings lend evidence for bidirectional effects between quality of life and anxiety symptoms. The transactional nature of the relationship between anxiety symptoms and quality of life warrant further investigation using a longitudinal cross-lagged design. CONCLUSION: The anxiety subscale of the SCL-90-R may be utilized by clinicians and researcher to make inferences about quality of life in addition to assessing anxiety symptoms in patients with schizophrenia.