Concept of disease in geriatric psychiatry

Latent subtypes of depression in a community sample of older adults: can depression clusters predict future depression trajectories?

Identifying sources of heterogeneity in late life depression remains an important focus of psychiatric investigation. Community samples are particularly informative since many older adults have clinically significant depressive symptoms but fail to meet criteria for major depression and older adults generally do not seek treatment for their depressive symptoms. The primary data used for these analyses were those collected in a community-based survey of over 3000 adults age 65 or older followed for up to ten years. Depressive symptoms were measured by the Center for Epidemiologic Studies-Depression scale (CES-D). Latent class analysis was used to identify clusters of participants based on their symptom profiles at baseline. Mixed models were used to examine trajectories of CES-D scores based on cluster assignment. A model with three unique clusters best fit the data. Cluster 1 (59%) had a low probability of any symptom endorsement. Cluster 2 (31%) endorsed as a group some negative affect and somatic symptoms but their endorsement of low positive affect did not differ from Cluster 1. Participants in Cluster 3 (10%) had a higher probability of endorsement of all symptoms compared to Clusters 1 and 2. The results did not appreciably differ when symptom severity was included. Cluster assignment was a significant predictor of change in CES-D score over the ten-year follow-up period, and the effects over time differed by sex. Depressive symptom profiles predict the longitudinal course of depression in a community sample of older adults, findings that are important especially in primary care settings.

Profiles of depressive symptoms in older adults diagnosed with major depression: latent cluster analysis

OBJECTIVE

To explore the underlying structure of symptom presentation in older adults with major depression by identifying homogeneous clusters of individuals based on symptom profiles.

DESIGN

Secondary data analysis using latent class cluster analysis.

SETTING

Clinical Research Center for the Study of Depression in Later Life conducted at Duke University.

PARTICIPANTS

Three hundred sixty-six patients age 60+ who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for major depression and were enrolled in a longitudinal naturalistic treatment study.

MEASUREMENTS

Responses to the 10 items of the Montgomery-Asberg Depression Rating Scale at the time of study enrollment.

RESULTS

The authors identified four latent clusters of older adults with major depression. Patients in Cluster 1 (47.2%) had mean scores of average severity for reported and apparent sadness and lassitude and low mean scores for reduced appetite. Patients in Cluster 2 (27.1%) had higher mean scores compared with Cluster 1 for all items, and particularly for apparent sadness. Patients in Cluster 3 (18.9%) had the lowest mean scores for both apparent and reported sadness, but a similar profile compared with Cluster 1 for inner tension, reduced sleep, reduced appetite, and concentration difficulties. Cluster 4 (6.8%) had the highest mean scores for each item. Both apparent and reported sadness accounted for a large amount of variance among the four clusters. Patients in Cluster 4 were more likely to have 12 or less years of education and/or one or more functional limitations.

CONCLUSION

The heterogeneity in symptom presentation among older adults diagnosed with major depression can potentially inform the development of DSM-V.

Towards a scientific taxonomy of depression

Many concepts have been introduced into the classification of depression, including manic-depressive/bipolar disorder depression, etc. Kraepelin's original concept of manic-depressive disorder has evolved into the concept of polarity, and bipolar and unipolar disorders. Psychiatric classification is characterized by an inflation of the diagnostic categories, including subtypes of depression. This rapid multiplier effect is primarily descriptive, and there is a need to rethink, in a pragmatic fashion, the classification system, in order to develop one that is likely to be of utility and which has a scientific basis. Is the time now right to ask whether there are essential conditions relevant to depression? I think that it is, and here I will introduce the notion with two such conditions. The first is early life stress disorder, and the second vascular depression. These conditions have reached a point where the data supports them as distinct entities. In this paper, the rationale for this is discussed.

Issues in co-morbid severe mental illnesses in HIV infected individuals

Patients with comorbid HIV and serious mental illnesses pose particular difficulties for clinicians. Presentation of several mental disturbances can be similar, and often significanlty complicate the management of advancing HIV disease. In this article, we will review the assessment and management of four serious mental conditions in HIV-infected patients: delirium, dementia, schizophrenia and bipolar disorder.