DNA polymorphism in the FKBP5 gene affects impulsivity in intertemporal choice.

INTRODUCTION: Impulsivity in intertemporal choice has been operationalized as "delay discounting", referring to the preference for a sooner, smaller reward. FK506 binding protein 5 (FKBP5) is a co-chaperone of the glucocorticoid receptor (GR). FKBP5 overexpression causes GR resistance, resulting in increased plasma cortisol levels. High cortisol levels are associated with low impulsivity in intertemporal choice. The aim of this study was to explore the effect of single nucleotide polymorphisms (SNPs) in FKBP5 on delay discounting. METHODS: The participants consisted of 91 healthy Japanese people (66 males and 25 females with a mean age of 40.9 ± 6.9 years). Each participant completed Kirby's monetary choice questionnaire (MCQ) and donated a whole blood sample. Five SNPs in FKBP5 were genotyped using the DigiTag2. SNP linear regression analyses with 100,000 permutations were conducted for the hyperbolic time-discount rate (k). RESULTS: Two SNPs were excluded from analysis because of their low minor allelic frequencies. The SNP rs1360780 showed a significant association; participants with more minor alleles (T) were less impulsive in intertemporal choice for delayed gain (multiplicity-corrected P = 0.047). DISCUSSION: The significant SNP rs1360780 is located in the region adjacent to the hormone response element (HRE)-binding sequence where transcription factors bind and alter the transcription of FKBP5. A minor allele (T) of rs1360780, which causes FKBP5 overexpression, may reduce impulsivity in intertemporal choice (i.e. delay discounting) via GR resistance and the subsequent high cortisol levels. This is the first study to demonstrate an association between FKBP5 and impulsivity in intertemporal choice.

Six-year stability of affective temperaments as measured by TEMPS-A.

BACKGROUND: A number of psychopathological and neurobiological studies on affective temperament have been conducted based on the assumption that temperament is a stable trait. However, few studies have actually assessed the long-term stability of affective temperament. The objective of this study is to evaluate the 6-year stability of affective temperaments as measured by the Temperament Evaluation of Memphis, Pisa, Paris and San Diego--Autoquestionnaire version (TEMPS-A) in a non-clinical adult population. SAMPLING AND METHODS: Study participants consisted of 178 Japanese white-collar workers (103 males and 75 females; mean age = 38.5 years, SD = 7.8) who completed the Japanese version of TEMPS-A twice over a 6-year interval, and who did not have either past or current DSM-IV affective, anxiety or psychotic disorders, as diagnosed with the Mini-International Neuropsychiatric Interview. The long-term stability of affective temperaments as measured by TEMPS-A was assessed by analyzing Pearson correlation coefficients for temperament scores over a 6-year period. RESULTS: Temperament scores were moderately to highly correlated over the 6-year period (depressive temperament, r = 0.59; cyclothymic temperament, r = 0.68; hyperthymic temperament, r = 0.82; irritable temperament, r = 0.66; anxious temperament, r = 0.74; p < 0.01 for all values). Pearson coefficients were in the range of 0.61-0.83 for males and 0.51-0.79 for females, while they were 0.56-0.85 for younger and 0.63-0.77 for older participants. All correlations were significant at p < 0.01, irrespective of temperament type, gender and age. CONCLUSIONS: Affective temperaments as measured by TEMPS-A exhibited good long-term stability and were robust, irrespective of temperament type, gender and age. Affective temperaments as measured by TEMPS-A may be considered to be stable traits, providing a sound basis for psychopathological and neurobiological studies. Limitations of this study include the fact that our sample was not drawn from the general community, it was entirely composed of Japanese participants and the size was not large.

Teachers' knowledge, beliefs and attitudes concerning schizophrenia- a cross-cultural approach in Japan and Taiwan.

BACKGROUND: Mental health literacy of the general public is essential for the effective promotion of society's mental health. However, there has been no investigation of the general public's mental health literacy with Japanese and Taiwanese socio-cultural backgrounds. METHODS: A total of 129 Japanese and 150 Taiwanese elementary school teachers were surveyed about knowledge, beliefs and attitudes concerning schizophrenia by means of a questionnaire with a vignette describing a case of the disease. Identification of the case, cause of the disease, coping behavior for the case, and perception of stigmatizing and supporting attitudes by parents and neighbors of the case were investigated. RESULTS: As a common finding with the studies in Western countries, only small percentages of the Japanese and Taiwanese respondents were able to make a correct identification. A further common finding was the emphasis on psychosocial factors as a cause of schizophrenia, as was the rejection of psychotropic medication, although future study is required to determine to what extent the respondents know about therapeutic procedures utilized by psychiatrists. Significantly stronger stigma perception was shown in the Japanese respondents than in the Taiwanese, which may be attributable to the high institutionalization rate in Japan. CONCLUSIONS: Japanese and Taiwanese teachers' knowledge, beliefs and attitudes regarding schizophrenia were similar to those found in the general public in Western societies. Although the present study is limited in sampling and the components of the mental health literacy investigated, several working hypotheses have been extracted from it to be tested in future investigations on the Japanese and Taiwanese and other Asian general public's mental health literacy.