Biomarkers of Bipolar Disorder in Late Life: An Evidence-Based Systematic Review

PURPOSE OF REVIEW

Review the current evidence on biomarkers for bipolar disorder in the older adults. We conducted a systematic search of PubMed MEDLINE, PsycINFO, and Web of Science databases using the MeSH search terms "Biomarkers", "Bipolar Disorder", "Aged" and and "Aged, 80 and over". Studies were included if they met the following criteria: (1) the mean age of the study population was 50 years old or older, (2) the study included patients with bipolar disorder, and (3) the study examined one type of biomarkers or more including genetic, neuroimaging, and biochemical biomarkers. Reviews, case reports, studies not in English and studies for which no full text was available were excluded. A total of 26 papers were included in the final analysis.

RECENT FINDINGS

Genomic markers of bipolar disorder in older adults highlighted the implication of serotonin metabolism, while the expression of genes involved in angiogenesis was dysregulated. Peripheral blood markers were mainly related with low grade inflammation, axonal damage, endothelial dysfunction, and the dysregulation of the HPA axis. Neuroanatomical markers reflected a dysfunction of the frontal cortex, a loss of neurones in the anterior cingulate cortex and a reduction of the hippocampal volume (in patients older than 50 years old). While not necessarily limited to older adults, some of them may be useful for differential diagnosis (neurofilaments), disease staging (homocysteine, BDNF) and the monitoring of treatment outcomes (matrix metalloproteinases). Our review provides a comprehensive overview of the current evidence on biomarkers for bipolar disorder in the older adults. The identification of biomarkers may aid in the diagnosis, treatment selection, and monitoring of bipolar disorder in older adults, ultimately leading to improved outcomes for this population. Further research is needed to validate and further explore the potential clinical utility of biomarkers in this population.

Pending challenges to e-mental health in the COVID-19 era: Acceptability of a smartphone-based ecological momentary assessment application among patients with schizophrenia spectrum disorders

Introduction

Concerns have been raised about ecological momentary assessment (EMA) acceptability among patients with schizophrenia spectrum disorders (SSD), which is of major relevance during the e-Mental health-focused COVID-19 pandemic.

Objectives

To investigate i) the levels of adherence to a passive smartphone-based EMA tool, the Evidence-Based Behavior (eB2), among SSD patients; and ii) putative predictors of this.

Methods

Sample: SSD (F20-29-ICD10) outpatients, age 18-64, without financial incentives, recruited over 17/06/2019-11/03/2020 at the Hospital Universitario Fundación Jiménez Díaz (Madrid, Spain). Those who accepted the eB2 installation -users- and those who did not -non-users- were compared in sociodemographic, clinical, premorbid adjustment, neurocognitive, psychopathological, insight and metacognitive variables by a multivariable binary logistic regression model.

Results

Sample (N=77): n=41 males; age: 47.69±9.76 years, n=24 users (31.2%). n=14 users (70%) had the eB2 installed at follow-up (median=14.50 weeks).

Multivariable binary logistic regression model on ‘user’ as outcome
	β	SE	Wald	p	OR	95% CI
Age	-0.075	0.038	3.910	0.048	0.928	0.861-0.999
Education level	-0.967	1.289	0.563	0.453	0.380	0.030-4.755
Early adolescence premorbid adjustment	-0.285	0.110	6.695	0.010	0.752	0.606-0.933
Trail Making Test A	-0.030	0.025	1.488	0.222	0.970	0.924-1.018
Trail Making Test B	-0.005	0.010	0.278	0.598	0.995	0.976-1.014
Cognitive Insight	0.062	0.061	1.043	0.307	1.064	0.944-1.200

X²=25.296,df=6,p<0.001. Nagelkerke-R²=44.7%. Correctly classified: 76.9%, users:54.5%, non-users:88.4%.

Conclusions

Acceptability of a smartphone-based EMA application among SSD patients was low. Age (young) and good premorbid adjustment predicted acceptability. e-Mental Health methods need to be tailored for patients with SSD. Otherwise, these highly vulnerable individuals may be neglected by e-health-based services in the post-COVID-19 years ahead.

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Optimizing the assessment of suicide attempters with a decision tree

Background

Optimizing psychiatric assessments could help to standardize the use of structured instruments in clinical practice. In recent years, several research groups have applied Computerized Adaptive Tests (CATs) to simplify assessments in depression, anxiety and also suicidal behaviors. We aimed to construct a shortened test to classify suicide attempters using a decision tree methodology that allows the integration of relevant clinical information, namely the history of past suicide attempts, in the construction of the test.

Methods

The sample was composed of 902 adult participants in three subsamples: first-time suicide attempters, psychiatric inpatients that never attempted suicide and healthy controls. The performance of a decision tree built using the items of a previously developed scale for suicidal risk was examined. The history of past suicide attempts was used to separate patients in the decision tree. The data was randomly divided in a training set and a test set. The test set, that contained 25% of the data, was used to determine the accuracy of the decision tree. Twenty-five cross-validations of this set up were conducted.

Results

The first four items of the decision tree classified correctly 81.4% of the patients.

Conclusion

As a result of a methodology based on decision trees that, contrary to CATs, can incorporate relevant information in building the test we were able to create a shortened test capable of separating suicidal and non-suicidal patients. Using all the information that is available improves the precision and utility of instruments adapted for psychiatric assessments.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Increased severity of suicidal behavior in impulsive aggressive patients exposed to familial adversities

BACKGROUND

The mechanisms by which childhood abuse and family history of suicidal behavior (FHS) lead to an increased risk of suicidal behavior are still unknown. Impulsive aggression may play an intermediate role. We investigated whether greater scores for aggression and impulsivity might be associated with the effects of FHS and/or childhood abuse on the severity of suicidal behavior.

METHOD

We examined the scores of three scales measuring impulsive aggression in a sample of 696 suicide attempters. We compared the highest and lowest scores with regard to reports of childhood abuse and FHS using adjusted multinomial regression models. Genetic polymorphisms of the serotonergic system known to be associated with impulsive aggression were also analyzed.

RESULTS

Patients with high impulsive aggressive scores showed significant differences in sociodemographic, clinical and suicidal features compared with patients with low impulsive aggressive scores. Adjusted results showed that combinations of some types of childhood abuse and FHS, particularly emotional abuse and emotional neglect, are associated with high impulsivity and hostility scores. The SS genotype of the serotonin transporter gene (5-HTTLPR) was associated with high levels of impulsivity when the subjects reported emotional abuse [odds ratio (OR) 5.55, 95% confidence interval (CI) 1.75-17.5] or physical abuse (OR 5.03, 95% CI 1.50-16.9) in their childhood.

CONCLUSIONS

Our results support the role of impulsive aggression as one of the links that may connect childhood abuse and FHS with severity of suicidal behavior.

Cost-efficiency of laboratory testing among psychiatric inpatients

BACKGROUND

A set of tests to rule out medical conditions among psychiatric inpatients is still to be defined. A first step in this direction is to determine the utility of lab tests commonly used by psychiatrists.

METHODS

Biochemical tests have been routinely performed on inpatients in a psychiatric hospitalization unit from 2006 to 2009. This study examines the prevalence of abnormal values in 1,278 laboratory tests performed on 894 patients. The number of subjects screened and the direct expenditure needed to find results outside the normal range were computed. Differences in clinical profiles were compared between diagnostic groups according to main diagnosis.

RESULTS

We found high rates of seropositive patients for human immunodeficiency virus (14.3%) and hepatitis B virus (15.7%). Most patients met at least one criteria of metabolic syndrome (67.6%). The detection of hepatic abnormalities was very efficient (65.71%), particularly for patients diagnosed with alcohol use disorders.

CONCLUSIONS

The cost-efficiency of lab tests in psychiatric units is greatly variable. Though results of this study may not be generalized due to the different prevalence of medical conditions, the methodology can be easily implemented across psychiatric services. Cost-effectiveness and costbenefit analyses are warranted.

Machine learning and data mining: strategies for hypothesis generation

Strategies for generating knowledge in medicine have included observation of associations in clinical or research settings and more recently, development of pathophysiological models based on molecular biology. Although critically important, they limit hypothesis generation to an incremental pace. Machine learning and data mining are alternative approaches to identifying new vistas to pursue, as is already evident in the literature. In concert with these analytic strategies, novel approaches to data collection can enhance the hypothesis pipeline as well. In data farming, data are obtained in an 'organic' way, in the sense that it is entered by patients themselves and available for harvesting. In contrast, in evidence farming (EF), it is the provider who enters medical data about individual patients. EF differs from regular electronic medical record systems because frontline providers can use it to learn from their own past experience. In addition to the possibility of generating large databases with farming approaches, it is likely that we can further harness the power of large data sets collected using either farming or more standard techniques through implementation of data-mining and machine-learning strategies. Exploiting large databases to develop new hypotheses regarding neurobiological and genetic underpinnings of psychiatric illness is useful in itself, but also affords the opportunity to identify novel mechanisms to be targeted in drug discovery and development.

Endophenotypes and suicide behaviour

BACKGROUND

Recent studies have suggested that genetic predisposition to suicidal behavior may be independent of the risk of suicide associated to mental disorders, such as affective disorders, schizophrenia or alcohol dependence. Given the suicidal behavior heterogeneity and its hereditary complexity, the need to find demonstrable intermediate phenotypes that may make it possible to establish links between genes and suicide behaviors (endophenotypes) seems to be necessary. The main objective is to review which are the candidate endophenotypes of suicidal behaviors.

METHODS

We carried out a non-systematic review of all published literature in English, French and Spanish in MEDLINE. The search terms were endophenotypes and suicide behaviors.

CONCLUSIONS

The main candidate endophenotypes of suicidal behaviors are neuropsychological (decision-making, executive functions), personality traits (impulsivity, aggressiveness, and neuroticism), neurochemistry (5-HIAA in CNS) and neuroimaging (fMRI of cerebral amygdala or PET of prefrontal cortex metabolism).

Severity of personality disorders and suicide attempt

OBJECTIVE

Severity of personality disorders (PDs) may be more useful in estimating suicide risk than the diagnosis of specific PDs. We hypothesized that suicide attempters with severe PD would present more attempts and attempts of greater severity/lethality.

METHOD

Four hundred and forty-six suicide attempters were assessed. PD diagnosis was made using the International Personality Disorder Questionnaire--Screening Questionnaire. PDs were classified using Tyrer and Johnson's classification of severity (no PD, simple PD, diffuse PD). Severity/lethality of attempts was measured with the Suicide Intent Scale, Risk-Rescue Rating Scale and Lethality Rating Scale.

RESULTS

Attempters with severe (diffuse) PD had more attempts than the other groups. After controlling for age and gender, this difference remained significant only for the younger age group and women. There was no relationship between severity of PDs and severity/lethality of attempts.

CONCLUSION

Younger female attempters with severe PD are prone to repeated attempts. However, the severity of PD was not related to the severity/lethality of suicide attempts.

Mood changes after delivery: role of the serotonin transporter gene

BACKGROUND

Polymorphic variations in the serotonin transporter gene (5-HTT) moderate the depressogenic effects of tryptophan depletion. After childbirth there is a sharp reduction in brain tryptophan availability, thus polymorphic variations in 5-HTT may play a similar role in the post-partum period.

AIMS

To study the role of 5-HTT polymorphic variations in mood changes after delivery.

METHOD

One thousand, eight hundred and four depression-free Spanish women were studied post-partum. We evaluated depressive symptoms at 2-3 days, 8 weeks and 32 weeks post-partum. We used diagnostic interview to confirm major depression for all probable cases. Based on two polymorphisms of 5-HTT (5-HTTLPR and STin2 VNTR), three genotype combinations were created to reflect different levels of 5-HTT expression.

RESULTS

One hundred and seventy-three women (12.7%) experienced major depression during the 32-week post-partum period. Depressive symptoms were associated with the high-expression 5-HTT genotypes in a dose-response fashion at 8 weeks post-partum, but not at 32 weeks.

CONCLUSIONS

High-expression 5-HTT genotypes may render women more vulnerable to depressive symptoms after childbirth.

Diagnostic stability and evolution of bipolar disorder in clinical practice: a prospective cohort study

OBJECTIVE

To evaluate the long-term stability of International Classification of Diseases-10th revision bipolar affective disorder (BD) in multiple settings.

METHOD

A total of 34 368 patients received psychiatric care in the catchment area of a Spanish hospital (1992-2004). The analyzed sample included patients aged > or =18 years who were assessed on > or =10 occasions and received a diagnosis of BD at least once (n = 1153; 71,543 assessments). Prospective and retrospective consistencies and the proportion of subjects who received a BD diagnosis in > or =75% of assessments were calculated. Factors related to diagnostic shift were analyzed with traditional statistical methods and Markov's models.

RESULTS

Thirty per cent of patients received a BD diagnosis in the first assessment and 38% in the last assessment. Prospective and retrospective consistencies were 49% and 38%. Twenty-three per cent of patients received a BD diagnosis during > or =75% of the assessments.

CONCLUSION

There was a high prevalence of misdiagnosis and diagnostic shift from other psychiatric disorders to BD. Temporal consistency was lower than in other studies.

No association between the Ser9Gly polymorphism of the dopamine D3 receptor gene and schizophrenia in a Spanish sample

This study aims to further evaluate the controversial association between the Ser9Gly polymorphism in codon 9 of the D3 dopamine receptor gene (DRD3) and schizophrenia in psychiatric inpatients acutely hospitalized in two general hospitals in Madrid, Spain. The Ser9Gly polymorphism of the DRD3 was examined in 178 schizophrenic patients, 286 patients with other psychiatric diagnoses, and 132 controls recruited. Genotype frequencies were in Hardy-Weinberg equilibrium. No association was found between schizophrenia and the Ser9Gly polymorphism of the D3 dopamine receptor gene.

New GABAA receptor alpha5 subunit gene polymorphism that may confound genotyping

We report the discovery of a new GABAA receptor alpha5 subunit gene polymorphism close to the polymorphism described by Glatt et al. (GT)5GCGTGC(GT)21. This new polymorphism is of great importance, because it means that non-denaturing acrylamide gels used to separate the different alleles of the polymorphism described by Glatt et al. cannot distinguish an allele with the sequence: (GT)4GCGTGC(GT)n from another allele with the sequence: (GT)4(GCGT)4GC(GT)(n-6). These gel fragments are separated by size, which would be the same in these two cases. An alternative would be to use an analysis method that can detect base changes, for instance, single strand conformation polymorphism (SSCP) or denaturing gradient gel electrophoresis (DGGE).

Dimensions of suicidal behavior according to patient reports

Five factor analyses with limitations explored the Suicidal Intent Scale (SIS) subscales reflecting suicidal behavior dimensions. This larger sample study conducts an exploratory factor analysis of the SIS. Two large samples of suicide attempters (N= 435 and N= 252) from a general hospital were studied. The validity of SIS subscales obtained from the factor analysis was investigated by examining the association between the subscales and clinical variables. There were two factors: expected lethality and planning. In both samples, male gender and depression tended to be associated with higher scores in both subscales (small to medium effect sizes). Hospitalization was associated with higher scores in both SIS subscales (medium to large effects) suggesting that these subscales were reasonably good predictors of suicide attempt severity. Clinicians assessing patient reports to establish the severity of suicide attempts need to ask questions regarding both dimensions: expected lethality and planning.

Plasma testosterone and pathological gambling

The authors studied plasma testosterone levels and psychological characteristics of male pathological gamblers. Twenty-nine male pathological gamblers and a group of healthy volunteers matched for age and gender were compared on levels of plasma testosterone and scores on the Eysenck Personality Questionnaire (EPQ) and the Psychopathic Deviance scale of the Minnesota Multiphasic Personality Inventory (MMPI). Plasma testosterone levels were similar in the pathological gambling and comparison group (476.06 ng/100 ml vs. 560.71 ng/100 ml). Patients had higher scores on the Neuroticism subscales of the EPQ (13.83 vs. 10.83) and the Psychopathic Deviance scale of the MMPI (27.03 vs. 21.03), but not on any of the other subscales of the EPQ. Testosterone levels did not correlate with the psychological ratings. Testosterone levels are probably not related to impulsivity in pathological gambling.

Diurnal variability of orofacial dyskinetic movements

OBJECTIVE

Instrumental methods to measure tardive dyskinesia (TD) have been introduced in the last few years to try to eliminate the differences in inter-rater reliability. After eliminating variations attributed to the use of different raters, it is clear that TD frequently shows fluctuations in severity contributing to a low test-retest reliability. In the present study the diurnal variability of dyskinetic movements was explored by a computerized technique using digital imaging processing to measure orofacial movements.

METHOD

Ten patients with persistent tardive dyskinesia were assessed three times a day once a week for four consecutive weeks.

RESULTS

Four patients had significant diurnal variations in the severity of dyskinetic movements and six did not have significant variations. The period of time between waking and the assessment, the severity of dyskinetic movements, and smoking were significantly different between these two groups.

CONCLUSION

Diurnal variations, particularly in relation to sleeping and smoking patterns, may need to be taken into account during longitudinal studies of tardive dyskinesia.