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Bruce G Pollock

Publications and source records attributed to Bruce G Pollock.

At least 19 recordsLinked to original sources

Multiscale dispersion entropy of resting-state EEG in older adults with Alzheimer's disease, mild cognitive impairment, and remitted major depressive disorder.

BackgroundMultiscale dispersion entropy (MDEnt) is a nonlinear EEG measure that quantifies brain complexity across time scales, reflecting both local and global brain dynamics. Previous research indicates lower complexity at short time scales in Alzheimer's disease (AD) compared to mild cognitive impairment (MCI) and healthy controls (HCs), with MCI also showing lower values than HCs. Major depressive disorder (MDD) has also been preliminarily linked to reduced complexity during acute episodes.ObjectiveTo assess whether MDEnt at short time scales can distinguish AD from MCI and HCs, and to examine complexity differences across additional groups, remitted MDD (rMDD) and rMDD + MCI, while exploring associations with cognitive performance.MethodsThe study included 316 older adults: 44 HCs, 46 with rMDD, 114 with MCI, 71 with rMDD + MCI, and 41 with AD. Resting-state, eyes-closed EEGs were analyzed using MDEnt at 24 ms (short) and 60 ms (long) time scales. Cognitive function was measured with the Montreal Cognitive Assessment and a composite cognitive score.ResultsShort time scale complexity was lowest in AD, followed by MCI, and highest in HCs; rMDD presence had no impact. Only AD showed reduced complexity at long time scales. Complexity at both time scales was significantly correlated with cognitive performance.ConclusionsThis study highlights the value of MDEnt to assess complexity at short time scale and differentiate individuals with AD, MCI, or HCs. Reduced complexity in these individuals may underlie their cognitive impairment. In contrast, our study suggests that any MDD impact on complexity is likely related to active depressive symptoms.

Humans↗

Emergence, persistence, and resolution of suicidal ideation during treatment of depression in old age.

INTRODUCTION: To determine the rate and clinical correlates of emergent, persistent, and resolved suicidal ideation during treatment of major depression in the elderly. METHODS: Based on the course of suicidal ideation before and during 12 weeks of antidepressant treatment, we classified 437 elderly patients (234 treated with paroxetine; 203 with nortriptyline) as either non-suicidal or as having "emergent", "persistent", or "resolved" suicidality. We compared the four groups on pretreatment demographic and clinical measures and with respect to depression, anxiety, and akathisia during treatment. RESULTS: Rates of emergent, persistent, and resolved suicidality were 7.8%, 12.6%, and 15.6%, respectively. Patients with persistent suicidal ideation were more likely to have recurrent depression than non-suicidal patients or patients whose suicidality resolved with treatment. At the start of treatment, patients in all three suicidal groups had lower self-esteem than non-suicidal patients. During the course of treatment, emergent suicidality was not associated with akathisia, nor did rates of emergent suicidality differ between paroxetine- and nortriptyline-treated patients. While at baseline the levels of depression and anxiety and agitation were similar in the four groups, patients with resolved suicidality had a favorable treatment response, while patients with emergent and persistent suicidality were more likely to maintain higher depression scores and had higher levels of anxiety and agitation during treatment. DISCUSSION: Emergence of suicidal ideation is not common but is clinically significant during treatment of late-life depression and may signal more difficult-to-treat-depression.

Affect↗

A model of anticholinergic activity of atypical antipsychotic medications.

BACKGROUND: Atypical antipsychotics clozapine, olanzapine, and quetiapine have significant affinity for the muscarinic receptors in vitro, while aripiprazole, risperidone, and ziprasidone do not. Dissimilarity in binding profiles may contribute to the reported differences in the anticholinergic effects of these antipsychotics. However, it is difficult with the available data to predict the likelihood of anticholinergic effects occurring with various doses of an atypical antipsychotic. METHODS: We developed a model to assess the potential anticholinergic activity (AA) of atypical antipsychotics at therapeutic doses. A radioreceptor assay was used to measure in vitro AA at 6 clinically relevant concentrations of aripiprazole, clozapine, olanzapine, quetiapine, risperidone, and ziprasidone. Using published pharmacokinetic data, in combination with the measured in vitro AA, dose-AA curves were generated. RESULTS: Clozapine, and to a lesser extent olanzapine and quetiapine showed dose-dependent increases in AA. At therapeutic doses, the AA (in pmol/mL of atropine equivalents) was estimated to range from 27-250, 1-15, and 0-5.4 pmol/mL for clozapine, olanzapine, and quetiapine, respectively. Aripiprazole, risperidone, and ziprasidone did not demonstrate AA at any of the concentrations studied. CONCLUSIONS: Therapeutic doses of clozapine, olanzapine, and, to a lesser extent, quetiapine are associated with clinically relevant AA.

Adult↗

Elevation in plasma Abeta42 in geriatric depression: a pilot study.

Elevated plasma amyloid beta 1-42 (Abeta42) level has been linked to increased risk for incident AD in cognitively-intact elderly. However, plasma Abeta levels in individuals with late-life depression (LLMD), especially those with a late age of onset of first depressive episode, who are at a particularly increased risk for Alzheimer's disease, have not been studied. We compared plasma Abeta in 47 elderly with LLMD with 35 controls and examined its relationships to age of onset of first depressive episode, antidepressant treatment (paroxetine or nortriptyline), and indices of platelet activation (platelet factor 4 and beta-thromboglobulin) and brain abnormalities. Results indicated that plasma Abeta42 levels and the Abeta42/40 ratio were elevated in the LLMD group relative to controls in the overall group analyses and in the age- and gender-matched groups. MRI data indicated that higher Abeta42/40 ratio was associated with greater severity of total white matter hyperintensity burden in LLMD. Plasma Abeta levels in LLMD were not influenced by age of onset of first depressive episode or antidepressant treatment and were not related to indices of platelet activation. Our preliminary results suggest that increased plasma Abeta42 and Abeta42/40 ratio are present in geriatric depression, and future studies should be done to confirm these findings and to determine their relationship to cognitive decline and brain abnormalities associated with LLMD.

Aged↗

Maintenance treatment of major depression in old age.

BACKGROUND: Elderly patients with major depression, including those having a first episode, are at high risk for recurrence of depression, disability, and death. METHODS: We tested the efficacy of maintenance paroxetine and monthly interpersonal psychotherapy in patients 70 years of age or older who had depression (55 percent of whom were having a first episode) in a 2-by-2, randomized, double-blind, placebo-controlled trial. Among patients with a response to treatment with paroxetine and psychotherapy, 116 were randomly assigned to one of four maintenance-treatment programs (either paroxetine or placebo combined with either monthly psychotherapy or clinical-management sessions) for two years or until the recurrence of major depression. Clinical-management sessions, conducted by the same nurses, social workers, and psychologists who provided psychotherapy, involved discussion of symptoms. RESULTS: Major depression recurred within two years in 35 percent of the patients receiving paroxetine and psychotherapy, 37 percent of those receiving paroxetine and clinical-management sessions, 68 percent of those receiving placebo and psychotherapy, and 58 percent of those receiving placebo and clinical-management sessions (P=0.02). After adjustment for the effect of psychotherapy, the relative risk of recurrence among those receiving placebo was 2.4 times (95 percent confidence interval, 1.4 to 4.2) that among those receiving paroxetine. The number of patients needed to be treated with paroxetine to prevent one recurrence was 4 (95 percent confidence interval, 2.3 to 10.9). Patients with fewer and less severe coexisting medical conditions (such as hypertension or cardiac disease) received greater benefit from paroxetine (P=0.03 for the interaction between treatment with paroxetine and baseline severity of medical illness). CONCLUSIONS: Patients 70 years of age or older with major depression who had a response to initial treatment with paroxetine and psychotherapy were less likely to have recurrent depression if they received two years of maintenance therapy with paroxetine. Monthly maintenance psychotherapy did not prevent recurrent depression. (ClinicalTrials.gov number, NCT00178100.).

Aged↗

CYP2D6 genotype and venlafaxine-XR concentrations in depressed elderly.

INTRODUCTION: The elderly are at increased risk for medication-related adverse events. Recent reports indicate that venlafaxine may put the elderly at increased risk of cardio- and cerebrovascular adverse events. We investigated the relationship between the CYP2D6 polymorphism and steady-state plasma concentration of venlafaxine (VEN) and its primary metabolite o-desmethylvenlafaxine (ODV) in elderly participants receiving venlafaxine-XR for major depression in order to explore the contribution of pharmacogenetics to medication tolerability. METHODS: Forty-six elderly participants received venlafaxine-XR for the treatment of major depression. CYP2D6 genotype and steady-state plasma levels of VEN and ODV were determined. RESULTS: Sixty-five percent of participants were homozygous of the wild type (WT) allele, whereas 35% carried one or more variant alleles associated with intermediate and poor 2D6 metabolizer status. VEN concentration per unit dose was significantly higher and ODV concentration per unit dose was significantly lower in participants who carried one or more variant alleles compared to participants who were homozygous for the WT allele. The VEN and ODV concentrations per unit dose were also correlated with creatinine clearance. CYP2D6 genotype was not associated with medication associated side-effects. CONCLUSIONS: Plasma dose-corrected concentrations of VEN and ODV correlated with genetically determined CYP2D6 enzymatic activity in depressed elders treated with venlafaxine-XR. This relationship was not masked by the effects of age-related illness or polypharmacy. Future clinical application of pharmacogenetics to examine 2D6-dependent medications may help reduce the incidence of medication adverse events particularly in those elders at higher risk for medication adverse events due to impaired renal or cardiac function.

Aged↗

What is the optimal duration of a short-term antidepressant trial when treating geriatric depression?

BACKGROUND: To determine the optimal duration of an antidepressant trial in elderly patients, the authors examined the probability of eventually responding to treatment based on early improvement. METHODS: Four hundred seventy-two elderly patients with major depression (nonpsychotic, nonbipolar) were treated under protocolized conditions for up to 12 weeks and assessed weekly with the Hamilton Rating Scale for Depression. The probability of full response after 12 weeks of treatment was calculated in patients who had not fully responded after periods of treatment that lasted for 4 to 10 weeks. RESULTS: Most of the patients who had shown a partial improvement after 4 weeks of treatment became full responders after 4 or more additional weeks of treatment. By contrast, only a few of those who were nonresponders became full responders even after up to 8 additional weeks of treatment. CONCLUSIONS: After 4 weeks of treatment, it is possible to reliably identify a subgroup of elderly patients with depression who are more likely to benefit from a change in their treatment than from a few additional weeks of treatment with the same agent.

Aged↗

Persistence of neuropsychologic deficits in the remitted state of late-life depression.

OBJECTIVE: Cognitive impairment in late-life depression (LLD) is prevalent, disabling, and persists despite the remission of depressive symptoms. This article characterizes neuropsychologic functioning during remission in LLD. METHODS: The authors examined longitudinal performance on a comprehensive neuropsychologic battery in 56 nondemented subjects age 60 or older who initially presented with an episode of nonpsychotic unipolar major depression and 40 nondemented, age- and education-equated comparison subjects with no history of depression. Subjects were assessed at baseline (in a depressed state) and one year later (when remitted). RESULTS: After one year, 45% of the LLD subjects were cognitively impaired despite remission of depression. Visuospatial ability, information-processing speed, and delayed memory were most frequently impaired; 94% of the patients who were impaired at baseline remained impaired one year later. Twenty-three percent of the patients who were cognitively normal while depressed developed impairment one year later. CONCLUSIONS: Most older individuals who are cognitively impaired during a depressive episode remain impaired when their depression remits. In addition, a substantial proportion of older depressed individuals who are cognitively intact when depressed are likely to be impaired one year later, although their depression has remitted.

Age Factors↗

Cardiovascular changes associated with venlafaxine in the treatment of late-life depression.

BACKGROUND: Potential cardiovascular side effects from venlafaxine-XR must be considered when prescribing this medication, especially in geriatric patients, who often present with comorbid medical conditions. METHODS: Participants age 60 and older with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of a major depressive episode without psychotic features were treated openly with venlafaxine-XR for 12 weeks during which venlafaxine-XR was titrated based on tolerability and response according to predefined guidelines. Sitting and standing blood pressures and heart rates were measured. A 12-lead electrocardiogram was obtained at baseline and at week 12. RESULTS: Sixty-two participants started treatment; 59 completed at least two weeks of the 12-week study. The mean final dose of venlafaxine-XR was 195.5 mg/day (standard deviation: 72.2). Twenty-four percent (95% confidence interval [CI]: 7.3%-40.7%) of initially normotensive participants and 54% (95% CI: 34.3%-74%) of those with preexisting hypertension experienced an increase in blood pressure. Twenty-nine percent (95% CI: 14.6%-43.4%) of participants developed orthostatic hypotension. Two participants experienced a clinically significant increase in QTc interval. One participant reported new-onset mild dizziness, whereas four participants reported new-onset tachycardia or palpitation. Overall, 17 unique participants (28.8%; 95% CI: 17.3%-40.4%) experienced a new-onset cardiovascular problem, potentially related to the study medication. CONCLUSION: Overall, venlafaxine-XR was well tolerated. However, similar to previous reports, venlafaxine-XR was associated with some undesirable cardiovascular effects in some of the participants. Systematic monitoring of cardiovascular parameters during treatment with venlafaxine-XR should be strongly recommended, especially in the elderly.

Age of Onset↗

Paroxetine treatment of primary insomnia in older adults.

OBJECTIVE: The goal of this study was to test the efficacy of paroxetine for primary insomnia in older adults. METHODS: Adults over age 55 with primary insomnia were randomly assigned to six weeks of double-blind treatment with paroxetine (N = 14) or placebo (N = 13). Outcome measures included persistence or resolution of insomnia; weekly diary measures of sleep quality, daytime alertness, and mood; and pre-/postpolysomnographic measures of sleep latency, wake time after sleep onset, and sleep efficiency. RESULTS: Although weekly diary-based measures showed improved subjective sleep quality, daytime alertness, and mood with paroxetine, the authors observed no effect on sleep efficiency or categorical response rates. CONCLUSION: Paroxetine appears to be ineffective for treating primary insomnia in old age.

Aged↗

Population pharmacokinetics in geriatric psychiatry.

Although geriatric patients are the major recipients of drugs, most research during drug development is conducted in healthy younger adults. Safe and effective drug therapy in the elderly requires an understanding of both drug disposition and response in older individuals. One of the major issues in studying the elderly relates to the ability to study a large number of people in a minimally invasive way. Population pharmacokinetics can be used to model drug concentrations from a large population of sparsely sampled individuals. Population pharmacokinetics characterizes both the interindividual (between-subject) and intraindividual (within-subject) variability, and can identify factors that contribute to pharmacokinetic and pharmacodynamic variability. Population pharmacokinetics can be used to aid in designing large clinical trials by simulating virtual data based on the study design. It can also be used to assess consistency of drug exposure and evaluate its effect on clinical outcome. This article reviews the methods used in pharmacokinetic modeling, as well as providing examples of population pharmacokinetic modeling, highlighting its application to geriatric psychiatry.

Adult↗

Paroxetine: population pharmacokinetic analysis in late-life depression using sparse concentration sampling.

AIM: To develop a population pharmacokinetic (PK) model using sparse sampling of long-term treatment with paroxetine in elderly depressed subjects, incorporating CYP2D6 genotype as well as other covariates. METHODS: Elderly subjects (age>or=70 years) with nonpsychotic, nonbipolar major depressive disorder from the inpatient and outpatient clinic were treated with paroxetine in a 5-year clinical trial investigating 'Maintenance Therapies in Late-Life Depression' (MTLD-2). Plasma concentrations were collected during regular visits. CYP2D6 genotype was determined using polymerase chain reaction (PCR) for each individual. A nonlinear mixed-effects model was developed with NONMEM for these subjects who received 10-40 mg day-1 of paroxetine during treatment. One- and two-compartment models with linear and nonlinear elimination (Michaelis-Menten) were evaluated. PK parameters as well as interindividual and residual variability were estimated. The effects of age, weight, sex, race and CYP2D6 genotypes on the pharmacokinetics of paroxetine were evaluated. RESULTS: One hundred and seventy-one subjects with a mean age of 77 years (range 69-95) and a mean weight of 72.0 kg (range 32.9-137.0) were enrolled in the MTLD-2 clinical trial. A total of 1970 paroxetine concentrations were available for population PK analyses. Approximately 10 samples were taken per subject. A two-compartment nonlinear PK model with additive and proportional error provided the best base model for description of the data. Weight and CYP2D6 polymorphisms were found to have a significant effect on maximal velocity (Vm), whereas sex had an effect on volume of distribution of the central compartment. The Vm estimates in each of the CYP2D6 phenotypic groups were: 125 microg h-1 in poor metabolizer (n=1), 182 microg h-1 in intermediate metabolizers (n=28), 454 microg h-1 in extensive metabolizers (n=36) and 3670 microg h-1 in ultra-rapid metabolizers (n=5). CONCLUSIONS: The population PK model adequately described paroxetine data in this elderly depressed population. The data indicate that female and male subjects with different CYP2D6 polymorphisms have different elimination rates and therefore may need to be dosed differently based on metabolizer genotype.

Age Factors↗

Decreasing pain and anxiety associated with patient-activated atrial shock: a placebo-controlled study of adjunctive sedation with oral triazolam.

INTRODUCTION: Implantable atrial defibrillators (IADs) have proved to be safe and effective in the management of atrial fibrillation. A potential limitation of self-activated IAD therapy is patient-reported pain and anxiety. The main objective of the present study was to determine whether triazolam improved patient perception of the shock experience or altered patient memory of shock discomfort relative to placebo. METHODS AND RESULTS: A total of 15 men and women (mean age: 59 +/- 6 years) were enrolled in this double-blind, placebo-controlled, crossover study of triazolam. Randomized study medication was administered orally 75 minutes prior to scheduled atrial shock delivery. Patient perception of the shock experience was assessed along with sedation, memory, anxiety, and mood. Triazolam reduced mean pre-shock anxiety (t= 2.98, df = 14, P = 0.01) and shock-related pain (t= 2.74, df = 13, P = 0.01) and intensity (t= 2.64, df = 13, P = 0.018) relative to placebo. Similarly, participants recalled less discomfort the morning after shock with triazolam than with placebo (t= 2.82, df = 11, P = 0.017). CONCLUSIONS: This study was the first to investigate the use of an oral benzodiazepine administered prior to patient-activated shock delivery with an IAD. Our data indicate that oral triazolam is beneficial in decreasing pain and anxiety associated with self-activated atrial defibrillation. If triazolam provides a similar benefit in the community to that which has been reported here, this medication could be offered to patients as an adjunct to intermittent IAD therapy.

Adjuvants, Anesthesia↗

The Anticholinergic Drug Scale as a measure of drug-related anticholinergic burden: associations with serum anticholinergic activity.

Anticholinergic Drug Scale (ADS) scores were previously associated with serum anticholinergic activity (SAA) in a pilot study. To replicate these results, the association between ADS scores and SAA was determined using simple linear regression in subjects from a study of delirium in 201 long-term care facility residents who were not included in the pilot study. Simple and multiple linear regression models were then used to determine whether the ADS could be modified to more effectively predict SAA in all 297 subjects. In the replication analysis, ADS scores were significantly associated with SAA (R2 = .0947, P < .0001). In the modification analysis, each model significantly predicted SAA, including ADS scores (R2 = .0741, P < .0001). The modifications examined did not appear useful in optimizing the ADS. This study replicated findings on the association of the ADS with SAA. Future work will determine whether the ADS is clinically useful for preventing anticholinergic adverse effects.

Aged↗

Relevance of assessing drug concentration exposure in pharmacogenetic and imaging studies.

Pharmacodynamic differences are difficult to interpret without drug concentration data. In particular, variability in drug exposure may confound the interpretation of pharmacogenetic, therapeutic outcome, and neuroimaging studies. Inter-individual variability in concentrations can be quite high due to variable adherence and pharmacokinetics. For example, clearance may be influenced by genetics, drug interactions, age and illness. We review findings that acute responses to selective serotonin reuptake inhibitors can have a concentration-response relationship using positron emission tomography and neuroendocrine measures. We also present preliminary evidence that the concentration-response relationship for paroxetine is influenced by genotypic differences at the serotonin transporter promoter. In large clinical studies, the accurate assessment of drug exposure can be challenging, with several techniques used to assess exposure. Population pharmacokinetics (Pop PK) is a method that is ideally suited for analysing concentration data from large trials because both patient-specific and population parameters can be determined with only a small number of plasma samples per patient. As opposed to relying on prescribed doses or a single trough level, the ability to determine more accurately exposure with Pop PK reduces the heterogeneity introduced by exposure variability. Pop PK hierarchic Bayesian approaches have been effective for characterizing anticonvulsants, antibiotics, antineoplastics and antiarrhythmics. We have recently successfully incorporated these pop PK analyses into routine assessments of elderly patients in clinical trials of selective serotonin reuptake inhibitors (SSRIs) and second generation antipsychotics. For the design and interpretation of neuroimaging, pharmacogenetic, and behavioural studies, the assessment of drug concentration exposure is therefore feasible and has potentially important ramifications.

Clinical Trials as Topic↗

Outcomes of late-life anxiety disorders during 32 weeks of citalopram treatment.

BACKGROUND: Anxiety disorders are common in later life, but little is known about the long-term benefits and risks of pharmacotherapy. METHOD: 30 patients aged 60 years and older, with a DSM-IV anxiety disorder, entered a 32-week trial of citalopram. Data gathered at baseline and follow-up included anxiety symptoms using Hamilton Rating Scale for Anxiety (HAM-A) scores, quality of life using the Medical Outcomes Study 36-item Short Form (SF-36), and sleep using the Pittsburgh Sleep Quality Index (PSQI). Data analysis consisted of mixed-effect repeated measures models of HAM-A scores and pre-post comparison of SF-36 and PSQI scores. RESULTS: 30 persons entered treatment; most (27/30) had a primary DSM-IV diagnosis of generalized anxiety disorder (2 had panic disorder; 1 had posttraumatic stress disorder). Three subjects discontinued study medication due to side effects, 5 were terminated because of nonresponse, and 5 dropped out of the study for other reasons; thus, 17 subjects (57%) completed 32 weeks of treatment. Subjects' HAM-A scores improved significantly, with continuing improvements up until about 20 weeks of treatment. On the basis of a criterion of reduction in HAM-A to < 10 during the trial, 60% (18/30) of subjects were responders. Those who completed the 32-week trial had significant improvements in sleep and quality of life-including social functioning, vitality, mental health, and role difficulties due to emotional problems. CONCLUSIONS: In this 32-week study of citalopram for elderly persons with anxiety disorders, 60% responded. Those who received a full course of treatment experience significant improvements in quality of life and sleep quality.

Age Factors↗

The metabolic syndrome is associated with reduced central serotonergic responsivity in healthy community volunteers.

CONTEXT: The pathobiology of the metabolic syndrome remains unclear. The central nervous system is likely to be involved via regulation of eating, physical activity, blood pressure, and metabolism. OBJECTIVE: The objective of this study was to test the hypothesis that low central serotonergic activity is associated with the metabolic syndrome. DESIGN, SETTING, PARTICIPANTS: This was a cross-sectional study of 345 healthy community volunteers, aged 30-55 yr, not taking medications for hypertension, lipid disorders, or diabetes. OUTCOME MEASURES: Central serotonergic responsivity was assessed with the iv citalopram challenge test. The serum prolactin area under the curve (AUC) over 150 min was calculated, and all analyses were adjusted for age, sex, plasma citalopram concentration, and baseline prolactin. The metabolic syndrome was defined according to the National Cholesterol Education Program (NCEP) and International Diabetes Federation (IDF) criteria. Insulin resistance was estimated by homeostasis model assessment. RESULTS: Compared with other individuals, persons meeting either NCEP or IDF criteria for the metabolic syndrome had lower mean prolactin responses (P < 0.05 for both). Using logistic regression, a decrease in prolactin AUC of 1 sd (-13.6 ng/ml.h) more than doubled the odds of having the metabolic syndrome (NCEP criteria: odds ratio, 2.38; 95% confidence interval, 1.14-4.97; P = 0.02; IDF criteria: odds ratio, 2.80; 95% confidence interval, 1.48-5.30; P = 0.002). Finally, the prolactin AUC was negatively associated with insulin resistance (beta = -0.03, P = 0.02). CONCLUSIONS: Corroborating previous evidence, the metabolic syndrome was associated with diminished brain serotonergic activity as reflected in a comparative blunting of the prolactin response to a selective serotonergic challenge. This association may have implications for the etiology, prevention, and treatment of the metabolic syndrome.

Adult↗