Preventive effect of morning light exposure on relapse into depressive episode in bipolar disorder.

OBJECTIVE: Light therapy has been suggested to have a curative effect on bipolar depression; however, preventive effects of light exposure on depressive episodes remain unclear. This study evaluated whether daytime light exposure in real-life situations was associated with a preventive effect on relapse into depressive episodes in patients with bipolar disorder. METHODS: This prospective, naturalistic, observational study was conducted in Japan between August 2017 and June 2020. Outpatients with bipolar disorder were objectively evaluated for daytime light exposure over 7 consecutive days using an actigraph that could measure ambient light at baseline assessment and then assessed at 12-month follow-up for relapse into mood episodes. RESULTS: Of 202 participants, 198 (98%) completed follow-up at 12 months and 78 (38%) experienced relapse into depressive episodes during follow-up. In a Cox proportional hazards model adjusting for potential confounders, a longer time above 1000 lux at daytime was significantly associated with decrease in relapse into depressive episodes (per log min; hazard ratio, 0.66; 95% confidence interval, 0.50-0.91). In addition, a higher average illuminance and longer time above 1000 lux in the morning exhibited a significant decrease in relapse into depressive episodes (per log lux and per log min; hazard ratio, 0.65 and 0.61; 95% confidence interval, 0.49-0.86 and 0.47-0.78, respectively). The association between daytime light exposure and relapse into manic/hypomanic/mixed episodes was not significantly different. CONCLUSION: A significant association was observed between increased daytime light exposure, mainly in the morning, and decreased relapse into depressive episodes.

Daytime light exposure in daily life and depressive symptoms in bipolar disorder: A cross-sectional analysis in the APPLE cohort.

OBJECTIVES: Controlled artificial daylight exposure, such as light therapy, is effective in bipolar depression, but the association between uncontrolled daytime light and depressive symptoms in bipolar disorder (BD) is unclear. This study investigated the association between daytime light exposure under real-life situations and depressive symptom in patients with BD. METHODS: This cross-sectional study enrolled 181 outpatients with BD. The average daytime light intensity and the total duration of light intensity of ≥1000 lux were recorded over 7 consecutive days using an actigraph that measured ambient light. Depressive symptoms were assessed using Montgomery-Åsberg Depression Rating Scale, and scores of ≥8 points were treated as depressed state. RESULTS: Ninety-seven (53.6%) subjects were depressed state. At higher average daytime light intensity tertiles, the proportion of depressed state was significantly lower (P for trend, 0.003). In multivariable analysis adjusted for age, employment status, age at onset of BD, Young Mania Rating Scale score, bedtime, and physical activity, the highest tertile group in average daytime light intensity suggested a significantly lower odds ratio (OR) for depressed state than the lowest tertile group (OR, 0.33; 95% confidence interval [CI], 0.14-0.75; P = 0.009). Similarly, the longest tertile group in light intensity ≥1000 lux duration was significantly associated with lower OR for depressed state than lowest tertile group (OR, 0.42; 95% CI, 0.18-0.93; P = 0.033). CONCLUSIONS: The findings suggest that greater daytime light exposure in daily life is associated with decreased depressive symptoms in BD.

Bright light therapy for sleep disturbance in dementia is most effective for mild to moderate Alzheimer's type dementia: a case series.

BACKGROUND: Sleep problems in people with dementia are common and place a high burden on caregivers. Although hypnotic agents are often used to treat sleep disturbances, their use is associated with a considerable number of high-risk side-effects such as daytime sleepiness, amnesia, and an increased frequency of falling. The administration of bright light therapy (BLT) in the morning was a non-pharmacological remedy that was expected to treat sleep disorders in patients with dementia by entraining the circadian rhythm to ameliorate disturbances to the normal sleep-wake cycle. However, there are some unsolved issues related to the application of BLT, including the types of dementia for which it is effective and its efficacy in the different stages of cognitive decline and dementia. Furthermore, a protocol for effective BLT has not yet been proposed. METHODS: In this study, we explored the efficacy of BLT in the treatment of 17 participants, including those with Alzheimer's type dementia (AD) (n = 8), vascular dementia (n = 4), and dementia with Lewy bodies (n = 5). Patients sat in front of the light box for 1 h/day from 0900 to 1000. The patients underwent treatment every day for 2 weeks. RESULTS: BLT led to the improvement of sleep disturbance in four participants, all of whom were AD patients. The four AD patients showed a shorter duration of illness and/or had mild to moderate AD. CONCLUSION: BLT could be an effective strategy for treating dementia patients, depending on their type and grade of their dementia. To confirm this hypothesis, it would be necessary to study a larger number of cases. Non-pharmacological therapies for sleep disorders should be emphasized as a safe form of treatment for patients with dementia.

The relationship between acoustic startle response measures and cognitive functions in Japanese patients with schizophrenia.

Recently, schizophrenia endophenotypes have been actively investigated to better understand the pathophysiology of schizophrenia. Past studies have shown that cognitive functions, including working memory and executive function, correlate with acoustic startle responses, such as prepulse inhibition (PPI), in patients with schizophrenia. The aim of this study was to investigate the relationship between cognitive functions and acoustic startle response in Japanese patients with schizophrenia. In 100 patients with schizophrenia, we evaluated cognitive function, using the Brief Assessment of Cognition in Schizophrenia, Japanese-language version (BACS-J), and acoustic startle responses, including acoustic startle reflex, habituation, and PPI (three different intensities: 82, 86, and 90 dB SPL, equivalent to signal-to-noise ratios of +12, +16, and +20 dB, respectively). Using multiple regression analysis, we examined the relationship between acoustic startle responses and BACS-J primary measures or composite score. Level of attention was associated with magnitude of habituation in schizophrenia (P = 0.0009, ß = -0.357). None of the other domains of cognitive function were significantly associated with any measure of acoustic startle response. This included attention regarding ASR (P = 0.513), PPI (P = 0.521-0.842), verbal memory (P = 0.423-0.981), working memory (P = 0.312-0.966), motor speed (P = 0.323-0.955), verbal fluency (P = 0.125-0.920), executive function (P = 0.118-0.470), and the BACS-J composite score (P = 0.230-0.912). In this first investigation of the relationship between cognitive functions and acoustic startle responses in Japanese patients with schizophrenia, attentional deficits correlated highly with the level of habituation. However, a replication study using other population samples is required to further investigate this relationship.

Effect of aripiprazole, risperidone, and olanzapine on the acoustic startle response in Japanese chronic schizophrenia.

BACKGROUND: Studies have also shown that differences in the kind of the antipsychotics influenced disruption of the sensorimotor gating system, including prepulse inhibition (PPI), acoustic startle reflex (ASR), and habituation (HAB). We investigated the influence on startle response in chronic schizophrenia in 20 patients with schizophrenia taking risperidone, 21 patients with schizophrenia taking olanzapine, and 20 patients with schizophrenia taking aripiprazole. METHOD: The patients who participated in this study were on maintenance therapy with only one antipsychotic drug for 4 months. We performed the test for the association between all PPI measures (ASR, HAB, and PPI at prepulse sound pressure intensities of 82, 86, and 90 dB) and each the risperidene, olanzapine, and aripiprazole groups, with analysis of covariance (ANCOVA; using age, duration of illness, and daily dose of the antipsychotic as covariates). Also, when significant difference was detected in ANCOVA, the differences of PPI measures between every pairs of two drug groups were tested as a post hoc analysis with the use of t test and Bonferroni's correction of multiple tests. RESULT: We found that PPI90 showed significant differences with ANCOVA among patients with schizophrenia taking each of the antipsychotics. When we performed a post hoc analysis for PPI90, the value was higher in the aripiprazole group than in the olanzapine group and higher in the risperidone group than in the olanzapine group. CONCLUSION: Aripiprazole and risperidone may improve PPI90. ASR, HAB, PPI82, and PPI86 were no different among the Japanese schizophrenic patient groups with different antipsychotics.

Prepulse inhibition of the startle response with chronic schizophrenia: a replication study.

Prepulse inhibition (PPI) deficit, the acoustic startle reflex (ASR) and habituation (HAB) impairment are considered to be endophenotypes for schizophrenia. The recent two studies have reported that a PPI deficit was detected in Japanese schizophrenic patients. We replicated that study using larger samples (115 schizophrenic patients and 111 normal controls) than the original study and a method same as original study. A startle response monitoring system was used to deliver acoustic startle stimuli, and to record and score the electromyographic activity of the orbicularis oculi muscle. We evaluated the startle measures of mean magnitude of ASR, HAB, and PPI at prepulse sound pressure intensities of 82dB (PPI82), 86dB (PPI86), and 90dB (PPI90). ASR was significantly different between schizophrenic patients and controls. HAB and all PPI session data from schizophrenic patients were significantly lower than in controls. In addition, we detected significant differences for ASR, HAB and each PPI (82, 86 and 90dB) between schizophrenic patients and controls with the use of multiple regression analysis. The gender and smoking state were not correlated with ASR, HAB or any PPI in multiple regression analysis. In conclusion, we were able to replicate the finding of HAB impairment and PPI deficit in chronic Japanese schizophrenic patients.