Toshikazu Ikuta

IMPORTANCE: Previous evidence has implicated corticostriatal abnormalities in the pathophysiology of psychosis. Although the striatum is the primary target of all efficacious antipsychotics, the relationship between its functional connectivity and symptomatic reduction remains unknown. OBJECTIVE: To explore the longitudinal effect of treatment with second-generation antipsychotics on functional connectivity of the striatum during the resting state in patients experiencing a first episode of psychosis. DESIGN, SETTING, AND PARTICIPANTS: This prospective controlled study took place at a clinical research center and included 24 patients with first-episode psychosis and 24 healthy participants matched for age, sex, education, and handedness. Medications were administered in a double-blind randomized manner. INTERVENTIONS: Patients were scanned at baseline and after 12 weeks of treatment with either risperidone or aripiprazole. Their symptoms were evaluated with the Brief Psychiatric Rating Scale at baseline and follow-up. Healthy participants were scanned twice within a 12-week interval. MAIN OUTCOMES AND MEASURES: Functional connectivity of striatal regions was examined via functional magnetic resonance imaging using a seed-based approach. Changes in functional connectivity of these seeds were compared with reductions in ratings of psychotic symptoms. RESULTS: Patients had a median exposure of 1 day to antipsychotic medication prior to being scanned (mean [SD] = 4.5 [6.1]). Eleven patients were treated with aripiprazole and 13 patients were treated with risperidone. As psychosis improved, we observed an increase in functional connectivity between striatal seed regions and the anterior cingulate, dorsolateral prefrontal cortex, and limbic regions such as the hippocampus and anterior insula (P < .05, corrected for multiple comparisons). Conversely, a negative relationship was observed between reduction in psychosis and functional connectivity of striatal regions with structures within the parietal lobe (P < .05, corrected for multiple comparisons). CONCLUSIONS AND RELEVANCE: Our results indicated that corticostriatal functional dysconnectivity in psychosis is a state-dependent phenomenon. Increased functional connectivity of the striatum with prefrontal and limbic regions may be a biomarker for improvement in symptoms associated with antipsychotic treatment.

BACKGROUND: The clinical benefit of memantine for Alzheimer's disease (AD) remains inconclusive. OBJECTIVE: We performed an updated systematic review and meta-analysis of the efficacy/safety of memantine in AD. METHODS: We included randomized trials of memantine for AD patients. Cognitive function scores (CF), behavioral disturbances scores (BD), and all-cause discontinuation were used as primary measures. Effect size based on a random-effects model was evaluated in the meta-analyses. RESULTS: Thirty studies (n = 7,567; memantine versus placebo: N = 11, n = 3,298; memantine + cholinesterase inhibitors (M+ChEIs) versus ChEIs: N = 17, n = 4,175) were identified. Memantine showed a significant improvement in CF [standardized mean difference (SMD) = -0.24, 95% confidence intervals (95% CIs) = -0.34, -0.15, p < 0.00001, I2 = 35% ] and BD (SMD = -0.16, 95% CIs = -0.29, -0.04, p = 0.01, I2 = 52%) compared with placebo. In the sensitivity analysis including only patients with moderate-severe AD, memantine was superior to the placebo in reducing BD without considerable heterogeneity (SMD = -0.20, 95% CIs = -0.34, -0.07, p = 0.003, I2 = 36%). Compared with ChEIs, M+ChEIs showed a greater reduction in BD (SMD = -0.20, 95% CIs = -0.36, -0.03, p = 0.02, I2 = 77%) and a trend of CF improvement (SMD = -0.11, 95% CIs = -0.22, 0.01, p = 0.06, I2 = 56%). However, in the sensitivity analysis of double-blind, placebo-controlled studies only, M+ChEIs showed a significant reduction in BD compared with ChEIs without considerable heterogeneity (SMD = -0.11, 95% CIs = -0.21, -0.01, p = 0.04, I2 = 40%). When performing the sensitivity analysis of donepezil studies only, M+ChEIs was superior to ChEIs in improving CF without considerable heterogeneity (SMD = -0.18, 95% CIs = -0.31, -0.05, p = 0.006, I2 = 49%). No differences were detected in all-cause discontinuation between the groups. CONCLUSIONS: The meta-analyses suggest the credible efficacy and safety of memantine in treating AD when used alone or in combination with ChEIs.

Accumulating evidence suggests that brain-derived neurotrophic factor (BDNF) is associated with the pathophysiology of major depressive disorder (MDD). In this mini review, we explored the association between BDNF and MDD using meta-analytic evidence. Our findings indicated that the Val66Met polymorphism in the BDNF gene was not associated with MDD or hippocampal volume in patients with MDD. However, plasma/serum levels of BDNF were decreased in patients with acute MDD compared with healthy controls. Both antidepressant treatment and electroconvulsive therapy increased plasma and serum levels of BDNF in patients with MDD. Val66Met polymorphism in the BDNF gene was associated with an antidepressant response in patients with MDD. Taken together, we did not detect any plausible evidence regarding Val66Met polymorphism in the BDNF gene contributing to a risk of MDD. However, peripheral BDNF levels are decreased in patients with MDD, and the polymorphisms are associated with treatment response. In conclusion, BDNF is best understood to be a biomarker for the state of MDD and its treatment response rather than a risk factor for MDD.

BACKGROUND: In light of the evidence for brain white matter (WM) abnormalities in schizophrenia, study of normal WM maturation in adolescence may provide critical insights relevant to the neurodevelopment of the disorder. Voxel-wise diffusion tensor imaging (DTI) studies have consistently demonstrated increases in fractional anisotropy (FA), a putative measure of WM integrity, from childhood into adolescence. However, the WM tracts that show FA increases have been variable across studies. Here, we aimed to assess which WM tracts show the most pronounced changes across adolescence. METHODS: DTI was performed in 78 healthy subjects aged 8-21 years, and voxel-wise analysis conducted using tract-based spatial statistics (TBSS). In addition, we performed the first meta-analysis of TBSS studies on WM development in adolescence. RESULTS: In our sample, we observed bilateral increases in FA with age, which were most significant in the left superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and anterior thalamic radiation. These findings were confirmed by the meta-analysis, and FA increase in the bilateral SLF was the most consistent finding across studies. Moreover, in our sample, FA of the bilateral SLF showed a positive association with verbal working memory performance and partially mediated increases in verbal fluency as a function of increasing age. CONCLUSIONS: These data highlight increasing connectivity in the SLF during adolescence. In light of evidence for compromised SLF integrity in high-risk and first-episode patients, these data suggest that abnormal maturation of the SLF during adolescence may be a key target in the neurodevelopment of schizophrenia.

We searched Embase, PubMed, and CENTRAL from inception until 22 May 2020 to investigate which antipsychotics and/or mood stabilizers are better for patients with bipolar disorder in the maintenance phase. We performed two categorical network meta-analyses. The first included monotherapy studies and studies in which the two drugs used were specified (i.e., aripiprazole, aripiprazole once monthly, aripiprazole+lamotrigine, aripiprazole+valproate, asenapine, carbamazepine, lamotrigine, lamotrigine+valproate, lithium, lithium+oxcarbazepine, lithium+valproate, olanzapine, paliperidone, quetiapine, risperidone long-acting injection, valproate, and placebo). The second included studies on second-generation antipsychotic combination therapies (SGAs) (i.e., aripiprazole, lurasidone, olanzapine, quetiapine, and ziprasidone) with lithium or valproate (LIT/VAL) compared with placebo with LIT/VAL. Outcomes were recurrence/relapse rate of any mood episode (RR-any, primary), depressive episode (RR-dep) and manic/hypomanic/mixed episode (RR-mania), discontinuation, mortality, and individual adverse events. Risk ratios and 95% credible interval were calculated. Forty-one randomized controlled trials were identified (n = 9821; mean study duration, 70.5 ± 36.6 weeks; percent female, 54.1%; mean age, 40.7 years). All active treatments other than carbamazepine, lamotrigine+valproate (no data) and paliperidone outperformed the placebo for RR-any. Aripiprazole+valproate, lamotrigine, lamotrigine+valproate, lithium, olanzapine, and quetiapine outperformed placebo for RR-dep. All active treatments, other than aripiprazole+valproate, carbamazepine, lamotrigine, and lamotrigine+valproate, outperformed placebo for RR-mania. Asenapine, lithium, olanzapine, quetiapine, and valproate outperformed placebo for all-cause discontinuation. All SGAs+LIT/VALs other than olanzapine+LIT/VAL outperformed placebo+LIT/VAL for RR-any. Lurasidone+LIT/VAL and quetiapine+LIT/VAL outperformed placebo+LIT/VAL for RR-dep. Aripiprazole+LIT/VAL and quetiapine+LIT/VAL outperformed placebo+LIT/VAL for RR-mania. Lurasidone+LIT/VAL and quetiapine+LIT/VAL outperformed placebo+LIT/VAL for all-cause discontinuation. Treatment efficacy, tolerability, and safety profiles differed among treatments.