Symptomatic remission and associated factors in a catchment area based population of older patients with schizophrenia

Abstract

Background

Symptomatic remission and its associated factors have been evaluated in several studies of younger schizophrenic patients. Although the number of older individuals with schizophrenia is rapidly growing, evaluations of remission in elderly patients are scarce and limited to samples of convenience, questioning their generalizability to unselected patient populations.

Methods

We assessed the rate of symptomatic remission in a cohort of older Dutch schizophrenic patients within a psychiatric catchment area. In addition, we examined the association of symptomatic remission with measures of mental health treatment, social functioning, cognition, mood, and quality of life.

Results

With a rate of 29.4%, symptomatic remission in this catchment area based cohort of older schizophrenic patients (mean age 68 years) was markedly lower than the rates reported for convenience samples. Remission was more frequent in schizoaffective patients, compared to patients with schizophrenia. Remitted patients were more adherent to psychiatric services and scored higher on measures of social functioning. No association with symptomatic remission could be demonstrated for cognition, mood, and quality of life.

Conclusion

The modest rate of symptomatic remission in this treated sample of elderly schizophrenic patients questions the notion that old age is associated with high levels of symptomatic remission. The concurrent validity of the remission concept in elderly patients merits further investigation, given the limited number of demonstrated associations.

Introduction

The proposal of a consensus definition of symptomatic remission in schizophrenia (Andreasen et al., 2005) has facilitated research on the heterogeneity of the long-term course of schizophrenia and fuelled a more optimistic view of outcome, in presenting remission as an attainable goal. According to this definition, symptomatic remission requires the absence or low intensity (severity criterion) of eight core symptoms of schizophrenia, maintained for a minimum period of six months (time criterion). In younger schizophrenic patients, a number of studies applying these criteria have demonstrated encouraging rates of remission.

Older patients constitute the fastest growing segment of the schizophrenia population (Cohen et al., 2008), displaying a distinct clinical profile. For instance, a substantial proportion of older schizophrenic patients has a later age at onset and women are markedly overrepresented compared to younger patients (Meesters et al., in press). Evidence for the common notion that aging is associated with a marked reduction of the intensity of psychotic symptoms stems largely from a range of longitudinal studies of patients with early onset schizophrenia, conducted in the last century (Harding, 2003, Harrison et al., 2001). More recently, for outpatients with early onset schizophrenia only a modest age-associated improvement in severity of positive symptoms was demonstrated, while negative symptoms remained stable (Jeste et al., 2003). Symptomatic remission, according to the new consensus definition, has been evaluated in two North American cohorts of older schizophrenic patients. Bankole et al. (2008) reported 49% of 198 patients (mean age 61 years) to be in remission (using the absence of psychiatric hospitalizations in the previous year as a substitute time criterion), while Leung et al. (2008) found 47% of 230 patients (mean age 56 years) demonstrating cross-sectional remission (no time criterion applied). However, because both studies only included community living patients with early onset schizophrenia, the generalizability of these rates to unselected elderly schizophrenic populations remains uncertain.

It is now generally accepted that symptomatic remission alone is too restricted a goal, and that the focus in schizophrenia treatment should be widened to the more demanding objective of recovery (Andreasen et al., 2005). Although a broadly accepted definition is still lacking, recovery is often viewed as a multidimensional concept which, over and above the reduction of symptoms, implies adequate psychosocial functioning and subjective well-being (Harvey and Bellack, 2009). Consequently, a range of other clinical and functional domains, such as cognition, mood, social performance and quality of life, contribute to recovery. In younger schizophrenic patients, several studies examining the relationship of symptomatic remission to these domains have reported positive associations. At the same time, the proportion of patients concurrently achieving symptomatic and functional remission was found to be low (Schennach-Wolff et al., 2009). For older schizophrenic patients, the two studies cited above reported diverging results. While Bankole et al. (2008) found symptomatic remission to correlate with a range of clinical and social variables, Leung et al. (2008) could not demonstrate remission status to predict functional skills, social competence or real-world performance. Therefore, in elderly patients as well, the implications of symptomatic remission for recovery still need further study.

To expand the data on symptomatic remission and its associated factors to a non-selected elderly population, we assessed a cohort of older Dutch schizophrenic patients. We aimed to include all patients with schizophrenia or schizoaffective disorder that were in contact with mental health services in a psychiatric catchment area. We hypothesized that (1) the rate of symptomatic remission in our catchment area based cohort would be lower compared to the rates reported for convenience samples, and (2) that remitted patients would demonstrate higher scores on measures of mental health treatment, social functioning, cognition, mood, and quality of life, as compared to non-remitted patients.