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Biomedical subjects

Rathi Mahendran

Publications and source records attributed to Rathi Mahendran.

17 recordsLinked to original sources
PubMed2026

Development and Validation of Machine Learning Models for Predicting Early Cognitive Decline Using Home Sensor-Derived Behavioral Data: Sensors in-Home for Elder Wellbeing (SINEW) Cohort Study.

BACKGROUND: As the global population continues to age, the prevalence of geriatric conditions, including dementia and frailty, is also increasing. Early identification of individuals at an elevated risk of these conditions, such as those presenting with mild cognitive impairment (MCI) or prefrailty, can provide a critical window for prompt intervention aimed at preventing or reversing disease progression. To promote such early identification, there is a burgeoning interest in the use of digital sensor technology and predictive modeling. OBJECTIVE: This study aimed to use a continuous, home-based monitoring sensor system for older adults to distinguish those exhibiting normal aging from those with MCI, early dementia, prefrailty, or frailty, and to predict their transition from normal aging to one of these conditions. METHODS: This longitudinal cohort study will recruit 200 community-dwelling adults aged ≥65 years with normal cognition or MCI at baseline. A multi-sensor system will be installed in participants' homes, including passive infrared motion sensors, door contact sensors, bed sensors, medication box sensors, wearable activity bands, and Bluetooth proximity beacons. These devices will continuously capture spatiotemporal activity patterns, mobility indicators, sleep behaviors, and medication-taking routines. Annual assessments will include standardized cognitive tests (eg, Montreal Cognitive Assessment, Mini-Mental State Examination, Rey Auditory-Verbal Learning Test, digit span, Color Trails Test, semantic fluency, Stroop), frailty measures (modified Fried phenotype, gait speed, grip strength), mental health scales, sleep quality, and psychosocial indicators. Sensor-derived features-such as gait variability, activity regularity, sleep fragmentation, and medication adherence patterns-will be integrated with clinical data to develop supervised machine learning models. Planned approaches include logistic regression, random forests, gradient boosting, and deep learning. Model performance will be evaluated using cross-validation and independent test sets. Primary metrics will include area under the receiver operating characteristic curve, sensitivity, specificity, precision, recall, and F1-score. Models will be benchmarked against gold-standard clinical diagnoses and validated using temporal subsets of the dataset. RESULTS: Enrollment for this study started in November 2019 and will continue until March 2030. As of June 2025, we have enrolled 138 participants. Full data analysis has yet to begin. CONCLUSIONS: We aim to develop a reliable and effective sensor system for in-home use that will facilitate the early detection of cognitive and physical decline. In so doing, it will add to our current understanding of digital biomarkers. It is common for older adults to seek clinical intervention only when their cognitive impairment has already reached an advanced stage. The implementation of readily deployable sensor systems within community settings presents us with opportunities for prompt intervention, which holds the potential for delaying or reversing disease progression and allowing for a greater number of functional and meaningful years.

Humans↗
PubMed2006

Newer antidepressant drug use in East Asian psychiatric treatment settings: REAP (Research on East Asia Psychotropic Prescriptions) Study.

AIMS: Antidepressant use in East Asia is poorly documented. We compared patients given newer and older antidepressants to test the hypothesis, suggested in the literature, that use of newer antidepressants is associated with treatment settings rather than specific diagnostic categories. METHODS: We compared rates of use of older (pre1990) vs. newer antidepressants among 1898 patients identified as antidepressant treated at 21 centres in five East Asian countries (China, Japan, Korea, Singapore, Taiwan) in 2003. Demographics, treatment setting and clinical factors associated with preferential use of newer drugs were tested in univariate and multivariate analyses. RESULTS: Newer antidepressants were included in the treatment regimens of 67.5% (N = 1282/1898) of study subjects. Prescription for newer antidepressants was significantly associated with younger age (z = -4.55, d.f. = 1888, P < 0.001), hospitalization [odds ratio (OR) 1.32, 95% confidence interval (CI) 1.07, 1.64, P < 0.01] and treatment within psychiatric hospitals (OR 1.59, 95% CI 1.27, 2.00, P < 0.001). On multivariate analyses, treatment with newer antidepressants was independently associated with younger age (P < 0.001), country (P < 0.001) and treatment within private hospitals (P < 0.001), but not with sex or diagnosis of affective or anxiety disorders (all P > 0.1). CONCLUSION: Demographic factors and treatment settings appear to influence antidepressant choice more than clinical factors such as diagnosis.

Adult↗
PubMed2006

Psychiatric comorbidity in first episode schizophrenia: a 2 year, longitudinal outcome study.

OBJECTIVE: We have previously documented a high prevalence of Axis I psychiatric comorbidity in our patients with first episode psychosis. This study sought to determine the longitudinal impact of Axis I psychiatric comorbidity on patients with first episode schizophrenia (FES) and we hypothesised that patients with psychiatric comorbidity were associated with poorer clinical and functional outcomes. METHOD: One hundred and forty two consecutively hospitalized FES patients were included. Socio-demographic information was obtained and the PANSS, SUMD, GAF, WHOQOL-Bref were used to assess psychopathology, insight, social/occupational functioning and quality of life respectively at baseline and at 6, 12, 18 and 24 months after discharge. RESULTS: Over time and compared with baseline scores, patients with Axis I psychiatric comorbidity (n=46, 32.4%) had significantly less reduction of their PANSS total and subscale scores, less improvement in their awareness of their psychiatric illnesses and symptoms at 12, 18 and 24 months and poorer insight into the consequences of their illness at 18 and 24 months. Poor insight at baseline was correlated positively with PANSS negative symptom subdomain, and negatively with GAF at 24 months. CONCLUSION: Axis I Psychiatric comorbidity was associated with worse prospective outcomes in hospitalized patients with first episode schizophrenia, and this highlights a greater need towards the early recognition and management of these conditions.

Activities of Daily Living↗
PubMed2006

Physical comorbidity, insight, quality of life and global functioning in first episode schizophrenia: a 24-month, longitudinal outcome study.

This prospective study sought to determine the clinical impact of physical comorbidity on patients with first episode schizophrenia (FES) and we tested the hypothesis that patients with physical comorbidity were associated with poorer clinical and functional outcomes. The severity of psychopathology, insight, social/occupational functioning and quality of life were evaluated using Positive And Negative Syndrome Scale (PANSS), Scale to assess Unawareness of Mental Disorder, Global Assessment of Functioning Scale (GAF), and World Health Organisation Quality of Life-Bref Scale (WHOQOL-Bref) respectively at baseline and at 6, 12, 18 and 24 months. Out of 142 patients, physical comorbidity was present in 21.8% (n=31) of the patients, and they were mainly related to the cardiovascular, respiratory and endocrine systems. Compared to baseline measurements, patients with physical comorbidity had greater awareness into the consequences of their psychiatric illness at 12 months, the need for treatment at 12 and 18 months, and better improvement of PANSS total and general psychopathology subscale scores at 24 months. FES patients with physical comorbidity also had less reduction in their WHOQOL-Bref scores in the physical health domain at 12 and 18 months and greater increase in the GAF scores at 18 and 24 months, indicating better subjective rating of quality of life and objective measure of their global functioning prospectively. Clinicians need to be aware of the substantial rates of physical comorbidity in FES patients which may not be necessarily associated with worse longitudinal outcomes and the findings should encourage even greater efforts at early identification and management of these physical conditions.

Adult↗
PubMed2006

Survey of sleep problems amongst Singapore children in a psychiatric setting.

BACKGROUND: Sleep problems are common among children and range from transient ones to chronic problems like snoring, somnambulism and bedwetting. Sleep problems in turn impact on children's health, learning, school performance, quality of life and are often closely related to mental health problems. Population based surveys have also revealed a strong association between sleep problems and behavioral and emotional symptoms in children. The objectives of our study were to estimate the prevalence of sleep problems in children and adolescents attending psychiatric services in Singapore and to identify the correlates of sleep problems in this population. METHODS: A total of 490 parents/guardians accompanying their children to the child guidance clinic consented to complete a questionnaire, which was used to collect both sociodemographic data and the frequency of sleep problems. These included sleep starts, confusional arousal, sleep talking, bruxism, sleep walking, sleep terrors, nightmares, sleep paralysis and nocturnal enuresis. Psychiatric diagnosis was determined from case record survey of the participating subjects. RESULTS: About 62.2% (95% CI 57.8%-66.6%) of the children suffered from at least one problem. Girls were significantly more likely to suffer from sleep problems when compared with boys (chi(2)=8.5, P<0.005). The significant predictors for sleep problems were gender, diagnosis of developmental disorders and a family history of sleep problems. CONCLUSIONS: The study highlights the need for child and adolescent psychiatrists to inquire about sleep problems since sleep disturbances of children are frequent and may not be self-reported.

Child↗
PubMed2006

The risk of suicidality with selective serotonin reuptake inhibitors.

Antidepressants are efficacious in the treatment of depression but they are not without side effects. The recent findings on the risk of suicide with selective serotonin reuptake inhibitor treatment, however, have raised serious concerns about the risk-benefit ratio of their use. The development of the concerns is traced and the risks discussed, particularly in the child and adolescent group. The prescriber needs to be aware of the issues and of the need for close clinical monitoring of patients started on selective serotonin reuptake inhibitor treatment.

Adolescent↗
PubMed2005

An inter-ethnic comparison study of clozapine dosage, clinical response and plasma levels.

The present study investigated clozapine dosage, plasma clozapine and metabolite levels, clinical and side-effect profiles in Asian versus Caucasian patients with chronic schizophrenia who were on stable maintenance treatment. Twenty Asian patients from Singapore and 20 Caucasian patients from Australia were systematically evaluated with the following rating scales: Positive and Negative Syndrome Scale for Schizophrenia, drug attitude scale (DAI-10), drug adverse reaction profile (Liverpool University Neuroleptic Side-effect Rating Scale), extrapyramidal side-effects scales (Abnormal Involuntary Movement Scale, Simpson and Angus Scale). Cigarette and caffeine consumption were recorded and steady-state plasma clozapine and metabolites levels were measured. Although Asian patients received a significantly lower mean clozapine dose (176 mg/day) than the Caucasian group (433 mg/day, P<0.001), plasma clozapine levels were similar between the groups. As a result, Asian patients had more than twice the effective clozapine concentration to dose ratio (P<0.001). The findings remained significant even after controlling for gender, body mass index, cigarette, alcohol and caffeine use. Conversely, the plasma metabolites (desmethylclozapine and clozapine N-oxide) to clozapine ratios were higher in the Caucasian patients (P<0.01). Compared to Caucasian patients, Asian patients appeared to have a lower dosage requirement for clinical efficacy. Hence, appropriate dose adjustment should be considered in Asian patients receiving maintenance clozapine therapy in clinical practice.

Adult↗
PubMed2005

Brief communication: factors affecting rehospitalisation in psychiatric patients in Singapore.

OBJECTIVES: To study the patterns of readmission in Singapore using a cohort of first admission schizophrenia patients to the state mental health institute. METHODS: A retrospective analysis of case records was done of first admission schizophrenia patients to the hospital from April 1993 to March 1994. Patients who had only one admission in the five years of follow up were compared to 'revolving door patients'. RESULTS: The cohort comprised 133 males (56.8%) and 101 females (43.2%). Seventy-eight patients (33.3%) had one admission to the hospital while 56 (23.9%) fulfilled the revolving door criteria. On performing a logistic regression we found sex (p = 0.02), shorter duration of illness (p = 0.01) and CPN referral (0.006) were significantly associated with revolving door phenomena. CONCLUSIONS: Our study has identified male gender, history of self-harm and a short duration of illness to be risk factors for 'revolving door' phenomena.

Adult↗
PubMed2004

Subjective quality of life in first episode schizophrenia spectrum disorders with comorbid depression.

Previous studies have reported high prevalence rates of depressive symptoms or syndromes in subjects with first episode psychosis, but data are lacking on the quality of life (QOL) in these subjects. This cross-sectional study seeks to compare the subjective QOL of these individuals with and without a comorbid depressive syndrome at baseline. Using the Structured Clinical Interview to Diagnose DSM IV-Axis I Disorders, the Scale to Assess Unawareness of Mental Disorders (SUMD), Positive and Negative Syndrome Scale (PANSS), Hamilton Rating Scale for Depression (HAM-D), and the World Health Organization Quality of Life-Bref Scale (WHOQOL-BREF), we evaluated 66 consecutive subjects with first episode schizophrenia spectrum disorders (schizophrenia, schizoaffective and schizophreniform disorders) in our Early Psychosis Intervention Program. We found that subjects with a comorbid depressive syndrome had greater awareness of their mental illness, its social consequences and treatment efficacy, but poorer overall QOL, especially in the physical, psychological health, social relationships and environmental domains. The poorer QOL in subjects with a comorbid depressive syndrome may be explained by the greater degree of insight in these patients and their attributing their troubles to poor health, unsatisfactory social support and negative environment. Alternative explanations are also possible, providing possible foci for psychological support and intervention.

Adolescent↗
PubMed2004

Genetic analysis of the thermolabile methylenetetrahydrofolate reductase variant in schizophrenia and mood disorders.

OBJECTIVE: An elevated homocysteine level has been reported for patients with schizophrenia and depression. We investigated the frequency of the common C667 T variant of the enzyme methylenetetrahydrofolate reductase in controls and patients of Chinese descent. METHODS: Controls with no history of mental disorder and patients diagnosed with schizophrenia, bipolar and unipolar disorders were recruited. Genomic DNA from all were genotyped for the C667 T polymorphism by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: There was no significant difference in genotype distributions or allele frequencies between controls and any of the diagnostic groups, although the frequency of the T allele was higher for all diagnostic groups and for both the male and female genders. When data was analyzed with the minor T allele as dominant, there was an excess of the T-containing genotypes in each of the patient groups compared with controls. For the difference between controls and all cases combined it almost reached statistical significance (P=0.077), with an odds ratio of 1.46 (95% confidence interval, 0.96-2.22). CONCLUSIONS: Although there was no significant association as measured by the P value, the odds ratio and confidence interval provided some evidence of increased risk for individuals with the T-containing genotypes. A minor role for this polymorphism in the pathogenesis of schizophrenia and depression could not be ruled out and would warrant further investigation.

Adult↗
PubMed2003

Tumor necrosis factor-alpha gene promoter polymorphisms in chronic schizophrenia.

BACKGROUND: Alterations in cytokine levels in patients with schizophrenia have been documented. Polymorphisms in these cytokine genes are thus potential genetic markers for schizophrenia. The aim of this study was to investigate four biallelic polymorphisms in the tumor necrosis factor-alpha (TNFalpha) gene promoter in relation to susceptibility to schizophrenia. METHODS: Three hundred two patients and 152 control subjects were genotyped and frequencies of genotypes and alleles were compared for the -1031T/C, -863C/A, -857C/T, and -308G/A polymorphisms. Genotype and allele frequencies were compared between controls and patients. RESULTS: There were statistically significant differences in genotype distribution and allele frequencies for the -308 polymorphism (p <.001). Genotype distribution and allele frequencies of the other three polymorphisms were not different between patients and reference controls. CONCLUSIONS: The -308 polymorphism or another genetic variant in linkage disequilibrium with it could be a susceptibility factor for chronic schizophrenia.

Adult↗
PubMed2003

Case-control and linkage disequilibrium studies of the tryptophan hydroxylase gene polymorphisms and major depressive disorder.

OBJECTIVES: Alterations in the level of the serotonin, serotonin uptake and the number of binding sites have been linked to affective illness. We investigated the association of tryptophan hydroxylase gene polymorphisms and unipolar depression in a case-control study design. METHODS: Patients and ethnically matched controls were genotyped for three polymorphisms of the tryptophan hydroxylase gene. RESULTS Significant difference in genotype frequency between patient and control groups was observed for the IVS7+218A >C polymorphism but not for the two promoter polymorphisms -1067G >A and -347T >G. Strong linkage disequilibrium among the three polymorphisms was also observed. CONCLUSIONS: As the sample size was small, the positive association would need to be replicated by family-based association studies or in a larger set of samples. As our results did not indicate association with either of the two promoter polymorphisms, there is a need to continue the search for the causative variant directly involved in the susceptibility to unipolar depression in Chinese as this polymorphism within the intron might not be the true susceptibility variant.

Case-Control Studies↗
PubMed2003

Mental health literacy beliefs. A comparison of psychiatric trained nurses and enrolled nurses in Singapore.

The views of mental health professionals may influence diagnosis and management options. This study reports nurses' views about the management of three common psychiatric disorders--schizophrenia, depression, and mania. Results demonstrate the effect of greater psychiatric education and training, received by psychiatric trained nurses, on mental health literacy.

Attitude of Health Personnel↗
PubMed2002

Tardive dyskinesia among Chinese and Malay patients with schizophrenia.

The prevalence of tardive dyskinesia (TD) was studied with the Abnormal Involuntary Movements Scale in Chinese and Malay patients with schizophrenia who were hospitalized in a Singapore state psychiatric institute. We also studied the relationship of neuroleptic-induced extrapyramidal side effects to TD. By using established criteria, the rates of TD were 40.6% for Chinese and 29.0% for Malays, higher than previously reported for Chinese subjects. Older age and lower current neuroleptic dose were significantly associated with TD. Multivariate analysis, after controlling for other salient risk variables, did not show a significant difference in TD prevalence rates between the two races. We conclude that suggested differences in interethnic rates of TD among Chinese, Malays, and Westerners are unlikely to exist and that any variation in prevalence is more likely to be determined by differences in duration of exposure and dose levels of neuroleptic drugs.

Adult↗
PubMedDate not supplied

Health-related quality of life and psychiatric comorbidity in first episode psychosis.

BACKGROUND: Quality of life (QOL) has been increasingly recognized as an important outcome measure in the care of patients with severe mental illnesses. This study seeks to evaluate the health-related QOL in patients with first episode psychosis and comparing those with psychiatric comorbidity to those without in an Early Psychosis Intervention Program. METHODS: Overall, 131 patients with first episode psychosis were evaluated on their principal Axis I diagnosis and any other comorbid diagnosis, severity of psychopathology, insight, social/occupational functioning, and QOL, respectively. RESULTS: Patients with psychiatric comorbidity scored lower on Positive and Negative Symptom Scale positive symptom subscale (z = -2.84, P <.01), had a greater awareness of their mental illness (z = -3.44, P <.001) and its social consequences (z = -3.24, P < 0.001), but lower ratings on the overall QOL (z = -3.06, P < 0.01) as well as in the individual domains (physical, psychological health, social relationships, environment, all P < .05) compared with patients without any psychiatric comorbidity. On multivariate analysis, being single and the presence of psychiatric comorbidity were associated with a poorer QOL in the various subdomains. CONCLUSIONS: The association of psychiatric comorbidity with poorer QOL warrants attention. The differences in the clinical correlates may provide potential targets for early identification and highlight needs that are significant to these patients with first episode psychosis and psychiatric comorbidity.

Adolescent↗