Psychotropic Medication Use Is Associated With Greater 1-Year Incidence of Dementia After COVID-19 Hospitalization.

Background: COVID-19 has been associated with an increased risk of incident dementia (post-COVID dementia). Establishing additional risk markers may help identify at-risk individuals and guide clinical decision-making. Methods: We investigated pre-COVID psychotropic medication use (exposure) and 1-year incidence of dementia (outcome) in 1,755 patients (≥65 years) hospitalized with COVID-19. Logistic regression models were used to examine the association, adjusting for demographic and clinical variables. For further confirmation, we applied the Least Absolute Shrinkage and Selection Operator (LASSO) regression and a machine learning (Random Forest) algorithm. Results: One-year incidence rate of post-COVID dementia was 12.7% (N = 223). Pre-COVID psychotropic medications (OR = 2.7, 95% CI: 1.8-4.0, P < 0.001) and delirium (OR = 3.0, 95% CI: 1.9-4.6, P < 0.001) were significantly associated with greater 1-year incidence of post-COVID dementia. The association between psychotropic medications and incident dementia remained robust when the analysis was restricted to the 423 patients with at least one documented neurological or psychiatric diagnosis at the time of COVID-19 admission (OR = 3.09, 95% CI: 1.5-6.6, P = 0.002). Across different drug classes, antipsychotics (OR = 2.8, 95% CI: 1.7-4.4, P < 0.001) and mood stabilizers/anticonvulsants (OR = 2.4, 95% CI: 1.39-4.02, P = 0.001) displayed the greatest association with post-COVID dementia. The association of psychotropic medication with dementia was further confirmed with Random Forest and LASSO analysis. Conclusion: Confirming prior studies we observed a high dementia incidence in older patients after COVID-19 hospitalization. Pre-COVID psychotropic medications were associated with higher risk of incident dementia. Psychotropic medications may be risk markers that signify neuropsychiatric symptoms during prodromal dementia, and not mutually exclusive, contribute to post-COVID dementia.

Mortality in association with antipsychotic medication use and clinical outcomes among geriatric psychiatry outpatients with COVID-19.

OBJECTIVES: Older adults are particularly vulnerable to the negative consequences of antipsychotic exposure and are disproportionally affected by higher mortality from coronavirus disease 2019 (COVID-19). Our goal was to determine whether concurrent antipsychotic medication use was associated with increased COVID-19 mortality in older patients with preexisting behavioral health problems. We also report on findings from post-COVID follow-ups. DESIGN: Retrospective observational study. PARTICIPANTS: Outpatients at a geriatric psychiatric clinic in New York City. MEASUREMENTS: Demographic and clinical data including medication, diagnosis and Clinical Global Impression Severity (CGI-S) scales on outpatients who had COVID-19 between February 28th and October 1st 2020 were extracted from the electronic health records (EHR) from the hospital. RESULTS: A total of 56 patients were diagnosed with COVID-19 (mean age 76 years; median age 75 years) and 13 (23.2%) died. We found an increased mortality risk for patients who were prescribed at least one antipsychotic medication at the time of COVID-19 infection (Fisher's exact test P = 0.009, OR = 11.1, 95% confidence interval: 1.4-96.0). This result remains significant after adjusting for age, gender, housing context and dementia (Logistic regression P = 0.035, Beta = 2.4). Furthermore, we found that most patients who survived COVID-19 (88.4%) recovered to pre-COVID baseline in terms of psychiatric symptoms. Comparison of pre- and post-COVID assessments of CGI-S for 33 patients who recovered from COVID-19 were not significantly different. CONCLUSION: We observed a higher COVID-19 mortality associated with concurrent antipsychotics use in older patients receiving behavioral health services. The majority of patients in our geriatric clinic who recovered from COVID-19 appeared to return to their pre-COVID psychiatric function. More precise estimates of the risk associated with antipsychotic treatment in older patients with COVID-19 and other underlying factors will come from larger datasets and meta-analyses.

Characterization of psychiatrically hospitalized college students.

Objective: To characterize contemporary college students requiring psychiatric hospitalization. Participants and methods: Sociodemographic and diagnostic information was gathered retrospectively and analyzed from the electronic medical records (EMRs) of the consecutive inpatient hospitalizations of 905 college students admitted to a psychiatric inpatient unit. Results: Significantly more females compared to males experienced the following: more hospitalizations, more family and financial stressors, more depression, and less psychotic and bipolar disorder. The most frequent diagnosis was a depressive disorder, followed by bipolar disorder, psychotic disorder, and personality disorder, most frequently borderline personality disorder. Half of participants had comorbid diagnoses with substance abuse most common. More than two-thirds of students endorsed social or intimate relationship, academic, and family challenges as psychosocial stressors. In all, 15% of participants had repeat admissions. Conclusions: The present study provides demographic data from a sample of psychiatrically hospitalized college students. Findings can help improve screening and identification of decompensation in college students.

A Model for Incident Review Committees in Behavioral Health Settings.

Despite the fact that incident review committees have been a key component of quality improvement in behavioral health settings for decades, specific models of how these committees are structured and operate are not well described. We present a model for an incident review committee that has been implemented in 2 large, academic acute care psychiatric hospitals. We believe the model not only permitted us to efficiently and effectively review untoward incidents, but that it also provided an approach to calibrating standards of care for the institution, engaging physicians in an interdisciplinary effort, promulgating a culture of quality review and improvement throughout the organization, promoting continuity and sustainability of the incident review process, and, most importantly, driving beneficial change in clinical practice. Demonstration of the effectiveness of this model requires formal investigation.

Differential burden of rare protein truncating variants in Alzheimer's disease patients compared to centenarians.

We compared coding region variants of 53 cognitively healthy centenarians and 45 patients with Alzheimer's disease (AD), all of Ashkenazi Jewish (AJ) ancestry. Despite the small sample size, the known AD risk variant APOE4 reached genome-wide significance, indicating the advantage of utilizing 'super-controls'. We restricted our subsequent analysis to rare variants observed at most once in the 1000 Genomes database and having a minor allele frequency below 2% in our AJ sample. We compared the burden of predicted protein altering variants between cases and controls as normalized by the level of rare synonymous variants. We observed an increased burden among AD subjects for predicted loss-of-function (LoFs) variants defined as stop-gain, frame shift, initiation codon (INIT) and splice site mutations (n = 930, OR = 1.3, P = 1.5×E-5). There was no enrichment across all rare protein altering variants defined as missense plus LoFs, in frame indels and stop-loss variants (n = 13 014, OR = 0.97, P = 0.47). Among LoFs, the strongest burden was observed for INIT (OR = 2.16, P = 0.0097) and premature stop variants predicted to cause non-sense-mediated decay in the majority of transcripts (NMD) (OR = 1.98, P = 0.02). Notably, this increased burden of NMD, INIT and splice variants was more pronounced in a set of 1397 innate immune genes (OR = 4.55, P = 0.0043). Further comparison to additional exomes indicates that the difference in LoF burden originated both from the AD and centenarian sample. In summary, we observed an overall increased burden of rare LoFs in AD subjects as compared to centenarians, and this enrichment is more pronounced for innate immune genes.

A Call to Restructure Psychiatry General and Subspecialty Training.

Dire shortages of psychiatrists with special expertise in geriatrics, substance abuse, forensics, and psychosomatics create barriers to care for populations with complex mental disorders and pose a significant public health concern. To address these disparities in access to care, we propose streamlining graduate medical education to increase efficiency and enhance cost-effectiveness while simultaneously increasing the number of psychiatric subspecialists in these key areas. We propose that trainees interested in subspecialties complete their general training in 3 years, while meeting ACGME required milestones, and then utilize their 4th year to complete subspecialty fellowship training. Eligible trainees would then qualify for psychiatry subspecialty certification and general psychiatry ABPN certification at the end of 4 years.

Haloperidol inactivates AMPK and reduces tau phosphorylation in a tau mouse model of Alzheimer's disease.

INTRODUCTION: The use of antipsychotic medications in Alzheimer's disease has been associated with an increased risk of mortality in clinical trials. However, an older postmortem literature suggests that those with schizophrenia treated in an era of exclusively conventional antipsychotic medications had a surprisingly low incidence of tau pathology. No previously published studies have investigated the impact of conventional antipsychotic exposure on tau outcomes in a tau mouse model of AD. METHODS: In two experiments, transgenic rTg (tauP301L) 4510 tau mice were treated with either haloperidol or vehicle and phosphotau epitopes were quantified using high-sensitivity tau ELISA. RESULTS: After treatments of 2 and 6 week's duration, mice treated with haloperidol evidenced a significant reduction in tau phosphorylation associated with an inactivation of the tau kinase AMPK. DISCUSSION: The data suggest that D2 receptor blockade reduces tau phosphorylation in vivo. Future studies are necessary to investigate the impact of this reduction on tau neuropathology.

Optimal treatment of Alzheimer's disease psychosis: challenges and solutions.

Psychotic symptoms emerging in the context of neurodegeneration as a consequence of Alzheimer's disease was recognized and documented by Alois Alzheimer himself in his description of the first reported case of the disease. Over a quarter of a century ago, in the context of attempting to develop prognostic markers of disease progression, psychosis was identified as an independent predictor of a more-rapid cognitive decline. This finding has been subsequently well replicated, rendering psychotic symptoms an important area of exploration in clinical history taking - above and beyond treatment necessity - as their presence has prognostic significance. Further, there is now a rapidly accreting body of research that suggests that psychosis in Alzheimer's disease (AD+P) is a heritable disease subtype that enjoys neuropathological specificity and localization. There is now hope that the elucidation of the neurobiology of the syndrome will pave the way to translational research eventuating in new treatments. To date, however, the primary treatments employed in alleviating the suffering caused by AD+P are the atypical antipsychotics. These agents are approved by the US Food and Drug Administration for the treatment of schizophrenia, but they have only marginal efficacy in treating AD+P and are associated with troubling levels of morbidity and mortality. For clinical approaches to AD+P to be optimized, this syndrome must be disentangled from other primary psychotic disorders, and recent scientific advances must be translated into disease-specific therapeutic interventions. Here we provide a review of atypical antipsychotic efficacy in AD+P, followed by an overview of critical neurobiological observations that point towards a frontal, tau-mediated model of disease, and we suggest a new preclinical animal model for future translational research.

Disease variants in genomes of 44 centenarians.

To identify previously reported disease mutations that are compatible with extraordinary longevity, we screened the coding regions of the genomes of 44 Ashkenazi Jewish centenarians. Individual genome sequences were generated with 30× coverage on the Illumina HiSeq 2000 and single-nucleotide variants were called with the genome analysis toolkit (GATK). We identified 130 coding variants that were annotated as "pathogenic" or "likely pathogenic" based on the ClinVar database and that are infrequent in the general population. These variants were previously reported to cause a wide range of degenerative, neoplastic, and cardiac diseases with autosomal dominant, autosomal recessive, and X-linked inheritance. Several of these variants are located in genes that harbor actionable incidental findings, according to the recommendations of the American College of Medical Genetics. In addition, we found risk variants for late-onset neurodegenerative diseases, such as the APOE ε4 allele that was even present in a homozygous state in one centenarian who did not develop Alzheimer's disease. Our data demonstrate that the incidental finding of certain reported disease variants in an individual genome may not preclude an extraordinarily long life. When the observed variants are encountered in the context of clinical sequencing, it is thus important to exercise caution in justifying clinical decisions.

Psychotic Alzheimer's disease is associated with gender-specific tau phosphorylation abnormalities.

Converging evidence suggests that psychotic Alzheimer's disease (AD + P) is associated with an acceleration of frontal degeneration, with tau pathology playing a primary role. Previous histopathologic and biomarker studies have specifically implicated tau pathology in this condition. To precisely quantify tau abnormalities in the frontal cortex in AD + P, we used a sensitive biochemical assay of total tau and 4 epitopes of phospho-tau relevant in AD pathology in a postmortem sample of AD + P and AD - P. Samples of superior frontal gyrus from 26 AD subjects without psychosis and 45 AD + P subjects with psychosis were analyzed. Results of enzyme-linked immunosorbent assay demonstrate that AD + P females, but not males, had significantly higher levels of phosphorylated tau in the frontal cortex. In males, but not females, AD + P was associated with the presence of α-synuclein pathology. These results support a gender dissociation of pathology in AD + P. The design of future studies aimed at the elucidation of cognitive and/or functional outcomes; regional brain metabolic deficits; or genetic correlates of AD + P should take gender into consideration.

Psychosis in Alzheimer's disease is associated with frontal metabolic impairment and accelerated decline in working memory: findings from the Alzheimer's Disease Neuroimaging Initiative.

OBJECTIVE: An ascendant body of evidence suggests that Alzheimer disease with psychosis (AD+P) is a distinct variant of illness with its own genetic diathesis and a unique clinical course. Impaired frontal lobe function has been previously implicated in AD+P. The current exploratory study, presented in two parts, evaluates both the regional brain metabolic and psychometric correlates of psychosis in a longitudinal sample of subjects with AD, made available by the Alzheimer's Disease Neuroimaging Initiative (ADNI). METHODS: In Part 1 of the study, 21 ADNI participants with AD who developed psychotic symptoms during the study but were not psychotic at baseline were matched with 21 participants with AD who never became psychotic during the study period, and mean brain [F(18)]fluorodeoxyglucose positron emission tomography (FDG-PET) Cerebral metabolic rate for glucose (CMRgl) by regions of interest (ROIs) were compared Additionally, 39 participants with active psychosis at the time of image acquisition were matched with 39 participants who were never psychotic during the study period, and mean brain FDG-PET CMRgl by sROI were compared. In Part 2 of the study, 354 ADNI participants with AD who were followed for 24 months with serial psychometric testing were identified, and cognitive performance and decline were evaluated for correlation with psychotic symptoms. RESULTS: Part 1: There were no regional brain metabolic differences between those with AD destined to become psychotic and those who did not become psychotic. There was a significant reduction in mean orbitofrontal brain metabolism in those with active psychosis. Part 2: Over the course of study follow-up, psychosis was associated with accelerated decline in functional performance as measured by the Functional Assessment Questionnaire, the Mini-Mental State Examination, and Forward Digit Span. CONCLUSION: In a sample drawn from the ADNI dataset, our exploratory FDG-PET findings and longitudinal cognitive outcomes support the hypofrontality model of AD+P. Focal frontal vulnerability may mediate the accelerated decline seen in AD+P.

Medical outcome of patients with dementia in a free-standing psychiatric hospital.

BACKGROUND: The hospital outcome of patients with dementia is significantly worse than that of cognitively intact persons of the same age admitted to medical or surgical units but has not been investigated in psychiatric settings. AIM OF STUDY: To determine the medical outcome of patients with dementia admitted for behavioral disturbance to a free-standing psychiatric hospital. METHODS: Emergency transfers from the psychiatric setting to a general hospital were used as proxies for medical deteriorations occurring among the 71 patients with dementia (age 78.4 ± 10.4 years; 40.1% males) and 71 age- and gender-matched nondementia control patients. The patients were identified in a cohort of 1000 patients consecutively admitted to a free-standing mental health institution. Logistic regression was used to determine the clinical and laboratory variables independently associated with medical deteriorations. RESULTS: A total of 30 patients with dementia and 25 nondementia patients were transferred to a general hospital after an acute medical deterioration (42.3% vs 35.2%, P = .38). Febrile illnesses and falls with head trauma were the most common reasons for transfers in the dementia group, in which they constituted more than half of medical deteriorations, a proportion significantly higher than in the control group (P = .011). Admission hemoglobin levels were the only independent predictor of medical deterioration in this geriatric sample. CONCLUSIONS: Although nearly 50% of patients with dementia admitted for behavioral disturbance to a free-standing psychiatric institution required transfer to a general hospital, their rate of medical deteriorations was similar to age-matched nondementia control patients.

Relationships between behavioral syndromes and cognitive domains in Alzheimer disease: the impact of mood and psychosis.

OBJECTIVES: Behavioral disturbances occur in nearly all Alzheimer disease (AD) patients together with an array of cognitive impairments. Prior investigations have failed to demonstrate specific associations between them, suggesting an independent, rather than shared, pathophysiology. The objective of this study was to reexamine this issue using an extensive cognitive battery together with a sensitive neurobehavioral and functional rating scale to correlate behavioral syndromes and cognitive domains across the spectrum of impairment in dementia. DESIGN: Cross-sectional study of comprehensive cognitive and behavioral ratings in subjects with AD and mild cognitive impairment. SETTING: Memory disorders research center. PARTICIPANTS: Fifty subjects with AD and 26 subjects with mild cognitive impairment; and their caregivers. MEASUREMENTS: Cognitive rating scales administered included the Mini-Mental State Examination; the Modified Mini-Mental State Examination; the Boston Naming Test; the Benton Visual Retention Test; the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychology Assessment; the Controlled Oral Word Test; the Wechsler Memory Scale logical memory I and logical memory II task; the Wechsler Memory Scale-Revised digit span; the Wechsler Adult Intelligence Scale-Revised digit symbol task; and the Clock Drawing Task together with the Clinical Dementia Rating Scale and the Neuropsychiatric Inventory. RESULTS: Stepwise regression of cognitive domains with symptom domains revealed significant associations of mood with impaired executive function/speed of processing (Δr = 0.22); impaired working memory (Δr = 0.05); impaired visual memory (Δr = 0.07); and worsened Clinical Dementia Rating Scale (Δr = 0.08). Psychosis was significantly associated with impaired working memory (Δr = 0.13). CONCLUSIONS: Mood symptoms appear to impact diverse cognitive realms and to compromise functional performance. Among neuropsychological indices, the unique relationship between working memory and psychosis suggests a possible common underlying neurobiology.

CALHM1 P86L polymorphism modulates CSF Aß levels in cognitively healthy individuals at risk for Alzheimer's disease.

The calcium homeostasis modulator 1 (CALHM1) gene codes for a novel cerebral calcium channel controlling intracellular calcium homeostasis and amyloid-ß (Aß) peptide metabolism, a key event in the etiology of Alzheimer's disease (AD). The P86L polymorphism in CALHM1 (rs2986017) initially was proposed to impair CALHM1 functionally and to lead to an increase in Aß accumulation in vitro in cell lines. Recently, it was reported that CALHM1 P86L also may influence Aß metabolism in vivo by increasing Aß levels in human cerebrospinal fluid (CSF). Although the role of CALHM1 in AD risk remains uncertain, concordant data have now emerged showing that CALHM1 P86L is associated with an earlier age at onset of AD. Here, we have analyzed the association of CALHM1 P86L with CSF Aß in samples from 203 AD cases and 46 young cognitively healthy individuals with a positive family history of AD. We failed to detect an association between the CALHM1 polymorphism and CSF Aß levels in AD patients. Our data, however, revealed a significant association of CALHM1 P86L with elevated CSF Aß42 and Aß40 in the normal cohort at risk for AD. This work shows that CALHM1 modulates CSF Aß levels in presymptomatic individuals, strengthening the notion that CALHM1 is involved in AD pathogenesis. These data further demonstrate the utility of endophenotype-based approaches focusing on CSF biomarkers for the identification or validation of risk factors for AD.

Incidence of tardive dyskinesia with risperidone or olanzapine in the elderly: results from a 2-year, prospective study in antipsychotic-naïve patients.

Tardive dyskinesia (TD) rates with second-generation antipsychotics (SGAs) are considered to be low relative to first-generation antipsychotics (FGAs), even in the particularly vulnerable elderly population. However, risk estimates are unavailable for patients naïve to FGAs. Therefore, we aimed to determine the TD incidence in particularly vulnerable, antipsychotic-naïve elderly patients treated with the SGA risperidone or olanzapine. The present work describes a prospective inception cohort study of antipsychotic-naïve elderly patients aged 55 years identified at New York Metropolitan area in-patient and out-patient geriatric psychiatry facilities and nursing homes at the time of risperidone or olanzapine initiation. At baseline, 4 weeks, and at quarterly periods, patients underwent assessments of medical and medication history, abnormal involuntary movements, and extra-pyramidal signs. TD was classified using Schooler-Kane criteria. Included in the analyses were 207 subjects (age: 79.8 years, 70.0% female, 86.5% White), predominantly diagnosed with dementia (58.9%) or a major mood disorder (30.9%), although the principal treatment target was psychosis (78.7%), with (59.4%) or without (19.3%) agitation. With risperidone (n=159) the cumulative TD rate was 5.3% (95% confidence interval (CI): 0.7, 9.9%) after 1 year (mean dose: 1.0±0.76 mg/day) and 7.2% (CI: 1.4, 12.9%) after 2 years. With olanzapine (n=48) the cumulative TD rate was 6.7% (CI: 0, 15.6%) after 1 year (mean dose: 4.3±1.9 mg/day) and 11.1% (CI: 0, 23.1%) after 2 years. TD risk was higher in females, African Americans, and patients without past antidepressant treatment or with FGA co-treatment. The TD rates for geriatric patients treated with risperidone and olanzapine were comparable and substantially lower than previously reported for similar patients in direct observation studies using FGAs. This information is relevant for all patients receiving antipsychotics, not just the especially sensitive elderly.

Atypical (second generation) antipsychotic treatment response in very late-onset schizophrenia-like psychosis.

INTRODUCTION: Symptom amelioration in older patients with very late onset schizophrenia-like psychosis (VLOSLP) is often difficult, with limited psychotropic response reports yielding variable findings. Information about atypical (second generation) antipsychotic use in this population is scant. METHODS: A consecutive sample of geriatric psychiatry outpatients and inpatients with psychotic disorders were retrospectively identified over a 31-month period based on systematic information abstraction from an electronic medical record (e-record). After exclusion criteria were applied, 8/138 outpatients and 13/362 inpatients met inclusion criteria for VLOSLP and had been naturalistically treated with an atypical antipsychotic during hospitalization or nine months of outpatient care. Mandatorily completed e-record standardized symptom severity response ratings were converted into positive treatment response thresholds. RESULTS: 38% of outpatients and 77% of inpatients (mean age = 76 years for both groups; mean age of onset of psychosis = 70 years for outpatients and 74 years for inpatients) met criteria for positive treatment response to an atypical antipsychotic (either aripiprazole, olanzapine, quetiapine, or risperidone) with sign/symptom amelioration, rather than eradication. CONCLUSIONS: Various atypical antipsychotics at geriatric doses yielded a positive treatment response in nearly two-thirds of VLOSLP patients. Patients with less chronic, more severe symptoms responded at a higher rate. Prospective, double-blind, placebo-controlled trials with representative subject samples are needed to validate these preliminary findings.

Frontal signal hyperintensities in mania in old age.

OBJECTIVE: Signal hyperintensities (SH) on magnetic resonance (MR) imaging have been associated with increased age and with mood disorders. Frontal and subcortical neuropathology has been implicated in the pathophysiology of mania and bipolar disorders. The authors assessed frontal and subcortical SH in elderly bipolar manic patients and the comparison group, and hypothesized that SH scores would be greater in the patient group. METHOD: MR imaging was performed in patients aged > or = 60 years with bipolar disorder, mania, and in a same-aged community comparison group. SH were rated blindly using the Boyko system. Frontal deep white matter and basal ganglia SH were assessed in the left and right hemispheres. RESULTS: SH scores were significantly greater in patients (N = 40) than the comparison group (N = 15) in frontal deep white matter (left: p = 0.003; right: p = 0.023) based on Mann-Whitney two-sample exact tests. The SH scores in the subcortical gray regions overlapped in these groups. In patients, higher right frontal SH scores were associated with later age at onset of mania. CONCLUSIONS: Frontal deep white matter SH may be increased in elders with bipolar disorder. Further study of the relationship of SH to age at onset in elders is warranted.

Geriatric psychiatry versus general psychiatry inpatient treatment of the elderly.

OBJECTIVE: The authors compared the clinical treatment given older psychiatric inpatients on a geriatric psychiatry unit and a general psychiatry unit. METHOD: The charts of 50 randomly selected general psychiatry inpatients over the age of 65 years and 50 inpatients from the geriatric psychiatry unit who were matched for age, gender, and primary diagnosis were reviewed. RESULTS: Significantly greater percentages of older inpatients treated on the geriatric psychiatry unit received complete organic medical workups, structured cognitive assessment, aging-sensitive aftercare referral, and monitoring of psychopharmacological side effects and blood levels than comparable patients on a general psychiatry unit. CONCLUSIONS: Geriatric psychiatry subspecialty inpatient care appears to be associated with distinct clinically relevant assessment and treatment advantages. Continuing geropsychiatric education of general psychiatrists is indicated.

Acute and chronic effects of citalopram on cerebral glucose metabolism in geriatric depression.

OBJECTIVE: In vivo studies of serotonin function have been limited by the lack of safe and selective pharmacologic agents and availability of suitable radiotracers. In the present study, the authors evaluated the cerebral metabolic effects of acute and continued administration of the selective serotonin reuptake inhibitor citalopram in patients with geriatric depression as a potential marker of serotonin dysfunction. METHODS: Six patients with geriatric depression and five comparison subjects underwent two resting positron emission tomography (PET) studies, performed after administration of a placebo infusion (Day 1) and a citalopram infusion (40 mg, Day 2). The patients were re-scanned after 8 weeks of treatment with the oral medication. RESULTS: The elderly comparison subjects demonstrated greater right-hemisphere cortical decreases than the patients. The depressed patients demonstrated greater left-hemisphere cortical decreases than comparison subjects. The depressed patients demonstrated greater increases in the right putamen and left occipital cortex. After 8 weeks of citalopram treatment, regional decreases and increases in metabolism were observed. CONCLUSION: These findings suggest regional deficits and also compensatory responses in the acute metabolic response to citalopram in the patients. These preliminary results suggest that the cerebral metabolic response to citalopram may be a useful marker of the pathophysiology of serotonin function in geriatric depression.