A Population-Based, Nationwide Longitudinal Study of Bipolar Disorder With Incident Dementia in Taiwan

Bidirectional association between major depressive disorder and dementia: Two population-based cohort studies in Taiwan

BACKGROUND

Major depressive disorder (MDD) and dementia are both major contributors to the global burden of disease. Despite existing literature on the association between MDD and dementia, there is a lack of a nationwide longitudinal cohort study that considers the competing risk of death. Therefore, this study assessed the bidirectional associations between MDD and dementia over an 11-year period in population-based settings, accounting for death as a competing risk.

METHODS

We conducted two population-based retrospective cohort studies in Taiwan. We identified 80,742 patients diagnosed with MDD in 2009-2010 and matched them with patients without MDD by sex, age, and year of diagnosis to assess the relative risk of dementia. We also identified 80,108 patients diagnosed with dementia in 2009-2010 and matched them with patients without dementia by sex, age, and year of diagnosis to assess the relative risk of MDD. All patients were followed until they received a diagnosis of new onset MDD or new onset dementia, their death, or the end of 2019. Cause-specific hazards models were used to estimate adjusted hazard ratios (aHRs).

RESULTS

The incidence density (ID) of dementia was higher in patients with MDD than in patients without MDD (7.63 vs. 2.99 per 1000 person-years), with an aHR of 2.71 (95% confidence interval [CI]: 2.55-2.88). The ID of MDD was higher in patients with dementia than in patients without dementia (12.77 vs. 4.69 per 1000 person-years), with an aHR of 2.47 (95% CI: 2.35-2.59).

CONCLUSIONS

This population-based study found a bidirectional association between MDD and dementia. Our findings suggest the need to identify dementia in patients with MDD and vice versa.

Prevalence of Comorbid Dementia in Late-life Depression and Bipolar Disorder: A Retrospective Inpatient Study

Background:

Dementia in patients with late-life mood disorders is clinically important.

Objective:

We aimed to investigate the prevalence of dementia in patients with late-life major depressive disorder (MDD) or bipolar disorder (BD) and to clarify the clinical characteristics associated with the diagnosis of dementia.

Methods:

The prevalence of dementia at hospital discharge and the clinical characteristics at hospitalization who are diagnosed with MDD or BD over 65 years of age, from the medical records of 684 patients who had been admitted from 2015 to 2020 were investigated.

Results:

A total of 66 patients with MDD (n = 50) and BD (n = 16) were analyzed. The prevalence of dementia was significantly higher in MDD than in BD (24.0% versus 0%; p = 0.026). The mean age at onset of MDD was significantly older in the MDD with dementia group than in the MDD without (76.9±6.3 years versus 62.2±14.0 years; p < 0.001). The rate of first depressive episode at this admission was significantly higher in the MDD with dementia group (91.7% versus 30.3%; p < 0.001). The diagnosis of dementia was significantly associated with lower scores for “insomnia early” (p = 0.019) and higher scores for “insight” (p = 0.049) on the 17-item Hamilton Depression Rating (HAMD-17) subscales and lower scores for “recall” (p = 0.003) on the MMSE subscales.

Conclusion:

The older age of first onset of depression, “insomnia early”, “insight” and “recall” may be useful indicators for a diagnosis of dementia in late-life depression.

Psychiatric disorders and risk of subsequent dementia: Systematic review and meta-analysis of longitudinal studies

OBJECTIVES

Although psychiatric disorders have been found to be associated with increased risk of dementia, previous findings are mixed, and the nature of these relationships remains poorly understood. We examined longitudinal associations between depression, anxiety, post-traumatic stress disorders (PTSD), bipolar disorder (BPD), psychotic disorders and subsequent dementia.

METHODS

We searched three databases for longitudinal, population-based studies investigating associations between psychiatric disorders and dementia (PROSPERO registration: CRD42020209638). We conducted narrative synthesis, and random-effects meta-analyses to obtain pooled estimates. We used meta-regression and stratified analyses to examine variation by sex, age-at-onset and follow-up time.

RESULTS

Fifty-seven citations met eligibility criteria. Most studies focussed on depression (n = 33), which was associated with subsequent all-cause dementia (pooled relative risk [RR]: 1.96, 95% confidence interval [CI]: 1.59-2.43; I2  = 96.5%), Alzheimer's Disease (pooled RR: 1.9, 95% CI: 1.52-2.38; I2  = 85.5%), and Vascular Dementia (pooled RR: 2.71, 95% CI: 2.48-2.97; I2  = 0). Associations were stronger in studies with shorter follow-up periods and for severe and late-onset depression. Findings regarding anxiety were mixed, and we did not find evidence of an overall association (pooled RR: 1.18, 95% CI: 0.96-1.45; I2  = 52.2%, n = 5). Despite sparse evidence, psychotic disorders (pooled RR: 2.19, 95% CI: 1.44-3.31; I2  = 99%), PTSD and BPD were associated with subsequent dementia.

CONCLUSIONS

People with psychiatric disorders represent high-risk groups for dementia, highlighting the importance of ongoing symptom monitoring in these groups. Findings regarding temporality and age-at-onset indicate that depression symptoms could reflect prodromal dementia for some individuals. Further longitudinal research is required to determine whether psychiatric disorders represent causal risk factors or early markers of dementia neuropathology.

Characteristics of Bipolar Patients with Cognitive Impairment of Suspected Neurodegenerative Origin: A Multicenter Cohort

Bipolar disorder is associated with an increased risk of dementia with aging. Little is known regarding this association, limiting appropriate diagnosis and management. We aimed to describe the characteristics of bipolar patients with late cognitive impairment for whom the hypothesis of an underlying neurodegenerative disease had been raised. We performed a retrospective multicenter study, recruiting bipolar patients over 50 years old from five French tertiary memory centers who had undergone cerebrospinal fluid (CSF) biomarker assessment for Alzheimer’s disease (AD). Clinical, neuropsychological, and paraclinical characteristics were analyzed and 78 patients were included. The mean age at the onset of cognitive impairment was 62.4 years (±9.2). The mean MMSE score was 22.8 (±4.5), the mean FAB was 11.7 (±3.9), and the mean FCRST was 15.8 (±7.4)/36.8 (±9.7) (free/total recall). A total of 48.6% of the patients displayed cognitive fluctuations, and 38.2% showed cognitive improvement during follow-ups; and 56.3% of the patients showed Parkinsonism, of which 12.7% had never received antipsychotics. Among patients who underwent DAT-scans, 35.3% displayed dopaminergic denervation; 10.3% of patients had CSF AD biological signature (“A+ T+” profile), while 56.4% had other abnormal CSF profiles. Thus, clinical presentation was dominated by executive dysfunction, episodic memory impairment, fluctuating cognition, and a high frequency of Parkinsonism. Specifically, high frequency of delusional episodes suggests limited tolerance of psychotropic drugs. Most patients had abnormal CSF biomarker profiles, but only a minority displayed AD’s specific biomarker signature. Therefore, while our results unveil shared common neurocognitive features in bipolar patients with cognitive impairment of suspected neurodegenerative origin they suggest a participation of various underlying pathologies rather than a common degenerative mechanism in the pathophysiology of this condition.

Cognitive performance in older-age bipolar disorder: Investigating psychiatric characteristics, cardiovascular burden and psychotropic medication

OBJECTIVE

This study aimed to explore a large range of candidate determinants of cognitive performance in older-age bipolar disorder (OABD).

METHODS

A cross-sectional study was performed in 172 BD patients aged ≥50 years. Demographics, psychiatric characteristics and psychotropic medication use were collected using self-report questionnaires and structured interviews. The presence of cardiovascular risk factors was determined by combining information from structured interviews, physical examination and laboratory assessments. Cognitive performance was investigated by an extensive neuropsychological assessment of 13 tests, covering the domains of attention, learning/ memory, verbal fluency and executive functioning. The average of 13 neuropsychological test Z-scores resulted in a composite cognitive score. A linear multiple regression model was created using forward selection with the composite cognitive score as outcome variable. Domain cognitive scores were used as secondary outcome variables.

RESULTS

The final multivariable model (N = 125), which controlled for age and education level, included number of depressive episodes, number of (hypo)manic episodes, late onset, five or more psychiatric admissions, lifetime smoking, metabolic syndrome and current use of benzodiazepines. Together, these determinants explained 43.0% of the variance in composite cognitive score. Late onset and number of depressive episodes were significantly related to better cognitive performance whereas five or more psychiatric admissions and benzodiazepine use were significantly related to worse cognitive performance.

CONCLUSION

Psychiatric characteristics, cardiovascular risk and benzodiazepine use are related to cognitive performance in OABD. Cognitive variability in OABD thus seems multifactorial. Strategies aimed at improving cognition in BD should include cardiovascular risk management and minimizing benzodiazepine use.

Degenerative dementias: Alterations of emotions and mood disorders

Degenerative dementias such as Alzheimer's disease and frontotemporal dementia result in distinct alterations in emotional processing, emotional experiences, and mood. The neuropathology of these dementias extends to structures involved in emotional processing, including the basolateral limbic network (orbitofrontal cortex, anterior temporal lobe, amygdala, and thalamus), the insula, and ventromedial frontal lobe. Depression is the most common emotion and mood disorder affecting patients with Alzheimer's disease. The onset of depression can be a prodromal sign of this dementia. Anxiety can also be present early in the course of Alzheimer's disease and especially among patients with early-onset forms of the disease. In contrast, patients with behavioral variant frontotemporal dementia demonstrate hypoemotionality, deficits in the recognition of emotion, and decreased psychophysiological reactivity to emotional stimuli. They typically have a disproportionate impairment in emotional and cognitive empathy. One other unique feature of behavioral variant frontotemporal dementia is the frequent occurrence of bipolar disorder. The management strategies for these alterations of emotion and mood in degenerative dementias primarily involve the judicious use of the psychiatric armamentarium of medications.

Bipolar Disorder Among Patients Diagnosed With Frontotemporal Dementia

OBJECTIVE

Previous studies have documented manic and hypomanic symptoms in behavioral variant frontotemporal dementia (bvFTD), suggesting a relationship between bipolar disorder and bvFTD.

METHODS

The investigators conducted a literature review as well as a review of the psychiatric histories of 137 patients with bvFTD, and patients with a prior diagnosis of bipolar disorder were identified. The clinical characteristics of patients' bipolar disorder diagnosis, family history, features of bvFTD, and results from fluorodeoxyglucose positron emission tomography (FDG-PET), as well as autopsy findings, were evaluated.

RESULTS

Among the 137 patients, 14 (10.2%) had a psychiatric diagnosis of bipolar disorder, eight of whom met criteria for bipolar disorder (type I, N=6; type II, N=2) 6-12 years preceding onset of classic symptoms of progressive bvFTD. Seven of the eight patients with bipolar disorder had a family history of mood disorders, four had bitemporal predominant hypometabolism on FDG-PET, and two had a tauopathy involving temporal lobes on autopsy. Three additional patients with late-onset bipolar I disorder proved to have a nonprogressive disorder mimicking bvFTD. The remaining three patients with bvFTD had prior psychiatric symptoms that did not meet criteria for a diagnosis of bipolar disorder. The literature review and the findings for one patient further suggested a shared genetic mutation in some patients.

CONCLUSIONS

Manic or hypomanic episodes years before other symptoms of bvFTD may be a prodrome of this dementia, possibly indicating anterior temporal involvement in bvFTD. Other patients with late-onset bipolar disorder exhibit the nonprogressive frontotemporal dementia phenocopy syndrome. Finally, a few patients with bvFTD have a genetic predisposition for both disorders.