Differential item functioning of the Geriatric Depression Scale in an Asian population.

BACKGROUND: The Geriatric Depression Scale (GDS) is widely used for screening and assessment of major depressive disorder (MDD). Screening scales are often culture-specific and should be evaluated for item response bias (synonymously differential item functioning, DIF) before use in clinical practice and research in a different population. In this study, we examined DIF associated with age, gender, ethnicity and chronic illness in a heterogeneous Asian population in Singapore. METHODS: The GDS-15 and Structured Clinical Interview for DSM-IV diagnosis of MDD were independently administered by interviewers on 4253 non-institutionalized community living elderly subjects aged 60 years and above who were users of social service agencies. Multiple Indicator Multiple Cause latent variable modelling was used to identify DIF. RESULTS: We found evidence of significant DIF associated with age, gender, ethnicity and chronic illness for 8 items: dropped many activities and interests, afraid something bad is going to happen, prefer staying home to going out, more problems with memory than most, think it is (not) wonderful to be alive, feel pretty worthless, feel (not) full of energy, feel that situation is hopeless. LIMITATIONS: The smaller number of minority Indian and Malay subjects and the self-report of chronic medical illnesses. CONCLUSIONS: In a heterogeneous mix of respondents in Singapore, eight items of the GDS-15 showed DIF for age, gender, ethnicity and chronic illness. The awareness and identification of DIF in the GDS-15 provides a rational basis for its use in diverse population groups and guiding the derivation of abbreviated scales.

Late-onset mania with psychosis associated with hypothyroidism in an elderly Chinese lady.

Late-onset bipolar disorder is rare and can be precipitated by organic brain disorders. While the association between hyperthyroidism and mania is well described, mania or hypomania precipitated by hypothyroidism is rare. The authors present late-onset bipolar disorder in a 72-year-old woman presenting with mania and psychosis, which appear to have been precipitated by autoimmune hypothyroidism. This case shows the importance of ascertaining the thyroid status in patients with mood and psychotic disorders, especially in elderly patients and in patients lacking prominent signs of thyroid disease.

The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-c30): validation of English version in Singapore.

OBJECTIVE: This study aimed to validate the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30, English version 3.0) in Singaporean cancer patients. METHODS: In a cross-sectional study, a heterogeneous sample of cancer patients (n = 57) self-administered a questionnaire containing the QLQ-C30, the Short Form 36 Health Survey (SF-36) and assessing health and sociodemographic status. Construct validity was assessed by testing a priori hypotheses that QLQ-C30 scales would be moderately or strongly correlated with SF-36 scales measuring similar dimensions of health-related quality of life (HRQoL) and that subjects reporting mild symptoms would have better HRQoL scores than those reporting severe symptoms. Internal consistency reliability was assessed using Cronbach's alpha. RESULTS: Strength of Spearman's correlations between the QLQ-C30 and SF-36 scales assessing similar dimensions of HRQoL ranged from 0.35 to 0.67. Subjects with mild symptoms had better scores than those with severe symptoms for all six QLQ-C30 HRQoL scales (p < 0.05 for five scales, Mann-Whitney U tests). Cronbach's alpha ranged from 0.19 for the cognitive functioning scale to 0.91 for the global QoL scale. CONCLUSION: This study provides preliminary evidence for the validity and reliability of the EORTC QLQ-C30 in English-speaking Singaporean cancer patients.