Affective temperaments are associated with the white matter microstructure in healthy participants.

OBJECTIVES: Five affective temperaments are regarded as potential precursors of bipolar disorder. These are depressive, cyclothymic, hyperthymic, irritable, and anxious temperaments. However, the neural substrates underlying these temperaments have not been identified. The aim of this study was to determine whether these temperaments are associated with specific neural substrates related to the brain white matter integrity in healthy participants. METHODS: We conducted a cross-sectional neuroimaging study of 71 healthy participants (38 males and 33 females) with affective temperaments. All participants screened for past and present psychiatric disorders. The scores of the five affective temperaments were measured by the temperament scale of Memphis, Pisa, Paris, and San Diego-autoquestionnaire. We analyzed the association between the fractional anisotropy (FA) and mean diffusivity (MD) of the brain white matter and these affective temperaments using tract-based spatial statistics (TBSS). RESULTS: The cyclothymic temperament score had a significant positive association with the FA and a significant negative association with the MD in the white matter in the right frontal part of brain. The hyperthymic temperament score was negatively associated with the MD in a wide area of the brain white matter. The anxious temperament score was positively associated with the FA in the bilateral frontal, temporal, and parietal regions of the brain white matter. The depressive and irritable temperament scores were not associated with either the FA or the MD. CONCLUSION: The present findings suggest that cyclothymic, hyperthymic, and anxious temperaments are associated with brain white matter integrity in healthy participants.

Cyclothymic temperament and glucose metabolism in the right superior parietal lobule.

Cyclothymic temperament possesses a central dimension that includes rapid fluctuations in mood and emotional instability, and it is regarded as a prodromal state of bipolar disorder. The aim of the present study is to explore the neural correlates of cyclothymic temperament. We used the data of 55 healthy participants in our previous study and analyzed the association between cyclothymic temperament scores rated by the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire (TEMPS-A) and the uptake of [18F]-FDG measured by positron emission tomography (PET). A whole brain analysis revealed a cluster of [18F]-FDG uptake significantly and positively associated with cyclothymic temperament scores, located in the right superior parietal lobule (SPL). Even after adjustment for relevant factors, there remained a significant cluster of [18F]-FDG uptake with cyclothymic temperament scores in the right SPL. In ROI analyses, there were similar significant peaks in the right SPL in association with cyclothymic temperament scores. These findings suggest that the right superior parietal lobule may be one of the neural correlates of cyclothymic temperament.

Trace lithium is inversely associated with male suicide after adjustment of climatic factors.

BACKGROUND: Previously, we showed the inverse association between lithium in drinking water and male suicide in Kyushu Island. The narrow variation in meteorological factors of Kyushu Island and a considerable amount of evidence regarding the role of the factors on suicide provoked the necessities of adjusting the association by the wide variation in sunshine, temperature, rain fall, and snow fall. METHODS: To keep the wide variation in meteorological factors, we combined the data of Kyushu (the southernmost city is Itoman, 26°) and Hokkaido (the northernmost city is Wakkanai, 45°). Multiple regression analyses were used to predict suicide SMRs (total, male and female) by lithium levels in drinking water and meteorological factors. RESULTS: After adjustment of meteorological factors, lithium levels were significantly and inversely associated with male suicide SMRs, but not with total or female suicide SMRs, across the 153 cities of Hokkaido and Kyushu Islands. Moreover, annual total sunshine and annual mean temperature were significantly and inversely associated with male suicide SMRs whereas annual total rainfall was significantly and directly associated with male suicide SMRs. LIMITATIONS: The limitations of the present study include the lack of data relevant to lithium levels in food and the proportion of the population who drank tap water and their consumption habits. CONCLUSIONS: The present findings suggest that trace lithium is inversely associated with male but not female suicide after adjustment of meteorological factors.

Low risk of male suicide and lithium in drinking water.

OBJECTIVE: Recently, several epidemiologic studies reported that lithium in drinking water may be associated with lower rates of suicide mortality at the population level, but other studies failed to confirm the association. The objective of the present study is to determine whether lithium in drinking water is associated with lower suicide rate after adjustment of potential confounding factors. METHOD: From 2010 to 2013, 274 mean lithium levels of 434 lithium samples in drinking water were examined in relation to suicide standardized mortality ratios (SMRs) in 274 municipalities of Kyushu Island in Japan. Weighted least squares regression analysis adjusted for the size of each population was used to investigate the association of lithium levels with suicide SMRs. The associations of lithium levels in drinking water with suicide SMRs (total, male, and female) were investigated adjusting for proportion of elderly people, proportion of 1-person households, proportion of people with college education or more, and proportion of people engaging in primary industry (adjusted model 1), and further adjustment was performed with overall unemployment rate, annual marriage rate, annual mean temperature, and annual postal savings per person (adjusted model 2). RESULTS: Lithium levels in drinking water were significantly (ß = -.169, P = .019) and inversely associated with male suicide SMRs but not total or female SMRs in the adjusted model 2. CONCLUSIONS: The present findings suggest that lithium in drinking water may be associated with the low risk of male suicide in the general population. Further studies are required to confirm these findings and investigate gender differences.

Identification of the neural correlates of cyclothymic temperament using a working memory task in fMRI.

BACKGROUND: Recently, we reported a significantly negative association of cyclothymic temperament scores with activations of the left lingual gyrus during esthetic judgments of paintings, suggesting that cyclothymic temperament may be associated with the left lingual gyrus. In view of potential associations of cyclothymic temperament, bipolar disorder and dementia, this study examined the relationship of temperament to lingual gyrus activity using a working memory task as a new context. METHODS: N-back tasks (0-, 1-, 2- and 3-back tasks) were performed on 34 healthy subjects using functional MRI. Multiple regression analyses were applied to measure the association between cyclothymic temperament scores and each of 4 beta images corresponding to 0-, 1-, 2- and 3-back tasks with gender, age and the other temperament scores (depressive, hyperthymic, irritable and anxious) as covariates. RESULTS: The whole brain analysis corrected for multiple comparisons revealed a significant activation of the left lingual gyrus associated with cyclothymic temperament scores in a new context-working memory for both 2- and 3-back tasks. LIMITATIONS: The number of subjects was relatively small. The subjects were almost medical staff or students and the results should be interpreted with caution. CONCLUSIONS: The present findings reconfirm that cyclothymic temperament may be associated with the left lingual gyrus.

Identification of the neural correlates of cyclothymic temperament using an esthetic judgment for paintings task in fMRI.

BACKGROUND: There is a well-known association between artistic creativity and cyclothymic temperament but the neural correlates of cyclothymic temperament have not yet been fully identified. Recently, we showed that the left lingual gyrus and bilateral cuneus may be associated with esthetic judgment of representational paintings, we therefore sought to investigate brain activity during esthetic judgment of paintings in relation to measures of cyclothymic temperament. METHODS: Regions of interest (ROI) were set at the left lingual gyrus and bilateral cuneus using automated anatomical labeling, and percent signal changes of the ROIs were measured by marsbar toolbox. The associations between percent signal changes of the ROIs during esthetic judgments of paintings and cyclothymic temperament scores were investigated by Pearson׳s coefficient. Moreover, the associations were further analyzed using multiple regression analysis whereby cyclothymic temperament scores were a dependent factor and percent signal changes of the 3 ROIs and the other 4 temperament scores were independent factors. RESULTS: There was a significantly negative association of cyclothymic temperament scores with the percent signal changes of the left lingual gyrus during esthetic judgments of paintings, but not with those of bilateral cuneus. Even after adjustment using multiple regression analysis, this finding remained unchanged. LIMITATIONS: The number of subjects was relatively small and the task was limited to appreciation of paintings. CONCLUSIONS: The present findings suggest that cyclothymic temperament may be associated with the left lingual gyrus.

Difference in brain activations during appreciating paintings and photographic analogs.

Several studies have investigated neural correlates of aesthetic appreciation for paintings but to date the findings have been heterogeneous. This heterogeneity may be attributed to previous studies' measurement of aesthetic appreciation of not only the beauty of paintings but also the beauty of motifs of the paintings. In order to better elucidate the beauty of paintings, it seems necessary to compare aesthetic appreciation of paintings and photographic analogs which included corresponding real images. We prepared for famous painters' pictures and their photographic analogs which were set up to resemble each painting in order to investigate the hypothesis that there exist specific neural correlates associated with the aesthetic appreciation for paintings. Forty-four subjects participated in functional magnetic resonance study which required comparisons of aesthetic appreciation of paintings of still life and landscape versus photographic analogs including corresponding real images of still life and landscape. Bilateral cuneus and the left lingual gyrus were activated in the comparison of aesthetic appreciation of paintings versus photographic analogs. In conclusion, the present findings suggest a possibility of the existence of specific neural correlates associated with the aesthetic appreciation for paintings and that bilateral cuneus and the left lingual gyrus may be involved.

Association between affective temperaments and regional gray matter volume in healthy subjects.

BACKGROUND: Affective temperaments such as cyclothymic and hyperthymic temperaments have been regarded as potential antecedents of bipolar disorder but the neural substrates underlying these temperaments have not been identified. The aim of this study is to determine whether these temperaments are associated with specific neural substrates in regional brain morphology in healthy subjects. METHODS: We conducted a cross-sectional neuroimaging study of 60 healthy subjects (30 males and 30 females) with affective temperaments. All participants underwent the Mini-International Neuropsychiatric Interview (MINI) to screen for the past and present psychiatric disorder. The scores of cyclothymic and hyperthymic temperaments were measured by the Temperament Scale of Memphis, Pisa, Paris and San Diego-Autoquestionnaire. We analyzed the association between voxel-based morphometry of the brain and these affective temperaments. RESULTS: Subjects classified as having high cyclothymic scores had a significantly larger gray matter volume of the left medial frontal gyrus (MFG) than low cyclothymic subjects. High hyperthymic males also had significantly larger gray matter volume of the left MFG than low hyperthymic males, but there was no difference in females. Subjects with both high cyclothymic and high hyperthymic temperaments demonstrated significantly larger gray matter volume of the left MFG than their counterparts. Region of interest analysis revealed that peaks of these clusters showed a significant positive correlation of the regional volume with temperament scores. LIMITATIONS: The subjects were relatively young and the number was relatively small. Due to the nature of a cross-sectional research design, we could not determine the causal relationship between temperament and the volume changes. CONCLUSIONS: These findings suggest that cyclothymic and hyperthymic temperaments in healthy subjects may have their morphological basis in the left MFG.

Hyperthymic temperament and rapid reaction time in brightness preference.

BACKGROUND: It is well-known that Type A behavior pattern is characterized by hard-driving, competitive behavior and time urgency. Also, people with hyperthymic temperament are known to have high energy levels and are full of plans. It is therefore hypothesized that hyperthymic temperament is associated with rapid processing and fast reaction time in making decisions. METHODS: Using data from our previous experimental studies (N=58) examining brightness judgment and brightness preference, reaction time (RT) was investigated in relation to hyperthymic temperament scores and fMRI signal changes of the left inferior orbitofrontal cortex during brightness judgment. RESULTS: RT for brightness judgment was significantly shorter than RT for brightness preference. Significant associations were found between RT for brightness preference and hyperthymic temperament scores, and RT for brightness preference and fMRI signal changes of the left inferior orbitofrontal cortex whilst performing brightness preference task. Multiple regression analysis revealed that RT for brightness preference task was significantly and negatively associated with hyperthymic temperament scores, and significantly and positively associated with fMRI signal changes of the left inferior orbitofrontal cortex. LIMITATIONS: It is uncertain whether the findings of RT (around 1s) can be extrapolated to routine life (around 24h) and whether RT for brightness preference can be generalized to a variety of daily activities. CONCLUSIONS: The present findings suggest that hyperthymic temperament is associated with rapid processing. Further studies are required to overcome the above limitations.

Hyperthymic temperament and brightness preference in healthy subjects: further evidence for involvement of left inferior orbitofrontal cortex in hyperthymic temperament.

BACKGROUND: Hyperthymic temperament has been generally accepted as one of premorbid temperament of bipolar disorders. Although several studies indicate that subjects with hyperthymic temperament receive more illuminance, our recent study suggests that the threshold of brightness and darkness judgment is not different between more and less hyperthymic subjects, and that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which has been reported to be associated with bipolar disorder. Therefore, at the next stage, it can be hypothesized that hyperthymic subjects may prefer brightness (i.e., heliotropism) and thereby seek illuminance, and that percent signal changes of left inferior orbitofrontal cortex during the preference task may be associated with hyperthymic temperament scores. METHODS: We compared brightness preference and un-preference between more and less hyperthymic subjects, and investigated percent signal changes of left inferior orbitofrontal cortex during brightness preference judgment, brightness un-preference judgment, and control task by using functional Magnetic Resonance Imaging (fMRI). RESULTS: There were significant differences in brightness preference judgment and un-preference judgment, showing that more hyperthymic subjects preferred brighter illuminace levels and un-preferred darker illuminance levels than less hyperthymic subjects. Moreover, fMRI signal changes of left inferior orbitofrontal cortex was significantly and negatively associated with hyperthymic temperament scores. LIMITATIONS: It is unknown why left but not right inferior orbitofrontal cortex was associated with hyperthymic temperament scores. CONCLUSIONS: The present findings suggest that more hyperthymic subjects may prefer brightness and un-prefer darkness than less hyperthymic subjects (i.e., heliotropism), and reconfirm that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which have been reported to be associated with bipolar disorders.

Hyperthymic temperament and brightness judgment in healthy subjects: involvement of left inferior orbitofrontal cortex.

BACKGROUND: Hyperthymic temperament has been generally accepted as one of premorbid temperament of bipolar disorders. Since recent several studies indicate an association between illuminance and hyperthymic temperament, it can be hypothesized that more hyperthymic temperament subjects have a different threshold of brightness or darkness perception in comparison with less hyperthymic temperament subjects. METHODS: We compared the threshold of brightness and darkness judgment between more and less hyperthymic subjects, and by simultaneously using fMRI we compared activations of whole brain between these subjects by two sample t-test. Furthermore, the association between the activations and hyperthymic temperament scores was analyzed. RESULTS: Although there was no significant difference in the threshold of brightness or darkness judgment between more and less hyperthymic subjects, there was a significant difference in activations of the regions including left superior temporal gyrus, left inferior orbitofrontal cortex, left triangular inferior frontal gyrus and left insula between these subjects. Moreover, there was a significantly positive association between a cluster containing left inferior orbitofrontal cortex and hyperthymic temperament scores. The common activated region of these two analyses (categorical and continuous ones) was determined as left inferior orbitofrontal cortex. LIMITATIONS: Limitation of the present study is a lack of brightness and darkness preference experiment between more and less hyperthymic subjects. CONCLUSIONS: The present findings suggest that the threshold of brightness and darkness judgment is not different between more and less hyperthymic subjects, and that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which has been reported to be associated with bipolar disorder.

Risk factors for suicide in Japan: a model of predicting suicide in 2008 by risk factors of 2007.

BACKGROUND: This study aims to comprehensively investigate the causal relationship between suicide and its risk factors in a longitudinal design. METHODS: A model was derived in which suicide rate in 2008 was longitudinally and comprehensively predicted by potential risk factors recorded one year before (2007) which included personal and interpersonal factors, medical factors, economic factors, climate factors, alcoholic factors, and ω-3 fatty-acid factors. RESULTS: In males, elderly population rate and complete unemployment rate predicted SMR of suicide significantly and positively whereas marriage rate and annual postal savings per person predicted SMR of suicide significantly and negatively. Also in females, complete unemployment rate predicted SMR of suicide significantly and positively whereas annual mean temperature predicted SMR of suicide significantly and negatively. LIMITATIONS: The limitations of this study are that predictions are based on the data of only the recent two years, that these epidemiological data cannot be always extrapolated to individuals, and that other factors should be taken into consideration to female suicide. CONCLUSIONS: The present findings suggest that male suicide may be accounted for by older age, more complete employment rate, less marriage rate and less annual postal savings whereas female suicide may be accounted for by more complete employment rate and lower annual mean temperature.

Type A behavior pattern: Bortner scale vs. Japanese-original questionnaires.

BACKGROUND: Type A behavior pattern (TABP) has been regarded as a putative risk factor for coronary heart disease and recent studies from our group suggest that TABP individuals, identified via the Bortner scale whose validity had been confirmed by structured interviews, may have a greater tendency towards hyperthymic temperament, shorter sleep time and shorter snooze time. Since the Bortner scale was developed in USA and may reflect western culture, it is necessary to reconfirm our findings using a Japanese questionnaire such as Coronary-prone Type Scale for Japanese (CTS) and Kwansei Gakuin's daily life questionnaire (KG questionnaire). METHODS: Fifty healthy subjects were assessed for TABP using the Bortner scale, as well as the CTS and KG questionnaires. Hyperthymic temperament was assessed via the Japanese standardized version of the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-auto questionnaire (TEMPS-A), while sleep time and snooze time were measured by actigraphy. RESULTS: Both CTS and KG questionnaire scores were significantly and positively associated with the Bortner scale scores. Although CTS and KG scores were significantly and positively associated with hyperthymic temperament scores, none were associated with sleep time or snooze time. LIMITATIONS: The number of subjects was relatively small. CONCLUSIONS: The findings suggest that Japanese questionnaires such as CTS and KG questionnaires are valid as measures of TABP. Moreover, the association between TABP and hyperthymic temperament was reconfirmed by both CTS and KG questionnaires, whereas the association between TABP and sleep pattern was not. As such, the present findings provide supportive evidence about the usefulness of CTS and KG questionnaires.

The effects of single and repeated psychiatric occupational therapy on psychiatric symptoms: assessment using a visual analogue scale.

The main aims of psychiatric occupational therapy are to improve daily activity, to enhance communication with others and to reinforce social adaptation. Also, substantial improvements in psychiatric symptoms have been reported, but the effects on psychiatric symptoms are yet to be established. In the present study, we investigated the effects of single and repeated administrations of psychiatric occupational therapy on psychiatric symptoms and determined whether the effects can be predicted. Our subjects were 215 inpatients or outpatients at our university hospital who participated in psychiatric occupational therapy. Five psychiatric symptoms (i.e. depressive mood, tension, irritability, anxiety and fatigue) were subjectively measured just before and just after each psychiatric occupational therapy by using a visual analogue scale (VAS). As a result, there was a significant short-term effect from single psychiatric occupational therapy, but there was no significant further improvement of any psychiatric symptom from repeated psychiatric occupational therapy. The VAS value at the beginning stage significantly predicted improvement of each psychiatric symptom. These findings suggest that single psychiatric occupational therapy can bring about a short-term effect, whereas repeated psychiatric occupational therapy cannot induce long-term effect (accumulated effect) on psychiatric symptoms, and that the improvement can be predicted by baseline psychiatric symptoms.