Cross diagnostic comparisons of quality of life deficits in remitted and unremitted patients with schizophrenia and bipolar disorder

Abstract

Background

Patients with schizophrenia (SCZ) and bipolar disorder (BD) have been found to report lower quality of life (QOL) compared to healthy controls separately. However, data are wanting on cross diagnostic comparisons of QOL within psychotic spectrum conditions. This study examined QOL differences and clinical predictors between schizophrenia (SCZ) and bipolar disorder (BD). Based on extant data, we hypothesized that patients with remitted SCZ and BD had comparable QOL levels, and that more severe symptoms and poorer psychosocial functioning predicted poorer QOL in our patients.

Methods

Two hundred and twenty-two sex and age-matched subjects (44 BD, 122 SCZ, 56 healthy controls) were assessed on their QOL, psychosocial functioning, symptomatology, and state of remission.

Results

Overall, SCZ patients had worse QOL in the environment domain (p = 0.008) and overall QOL (p = 0.007) compared with BD patients. Both patient groups in remission had similar QOL, while unremitted SCZ patients reported poorer QOL in all domains compared to unremitted BD patients (p < 0.01). Within patients, greater severity of negative symptoms and poorer psychosocial functioning were associated with poorer QOL (p < 0.05).

Discussion

Remission status affected QOL in both patient groups. The association of worse QOL with greater negative psychotic psychopathology and poorer psychosocial functioning highlighted potential clinical markers of QOL, which can aid in the management of psychotic spectrum disorders.

Introduction

The World Health Organization has defined quality of life (QOL) as “an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns” (WHOQOL Group, 1998), and which is also an important outcome measurement for people suffering from mental illness (Kugo et al., 2006, Brissos et al., 2008, Woon et al., 2010, Sidlova et al., 2011, Xiang et al., 2012). Quality of life has been examined in patients with psychotic spectrum conditions such as schizophrenia (Kugo et al., 2006, Woon et al., 2010, Sidlova et al., 2011, Xiang et al., 2012) and bipolar disorder (Yatham et al., 2004, Sierra et al., 2005, Gutiérrez-Rojas et al., 2008, Latalova et al., 2010). Specifically, subjective QOL is said to be a patient-centric measurement as it allows patients to convey how well they are coping as well as any difficulties they may face in their daily lives (Brissos et al., 2008). These patients with schizophrenia or bipolar disorder generally reported significantly lower subjective QOL compared with healthy controls (Ritsner et al., 2000, Brissos et al., 2008, Yen et al., 2008, Saarni et al., 2010). However, studies directly comparing the QOL between patients with schizophrenia (SCZ) and bipolar disorder (BD) are sparse and inconsistent, with some documenting no difference between the two patient groups (Yen et al., 2008, Cotton et al., 2010, Amini and Sharifi, 2012) SCZ patients reporting significantly better subjective QOL than affective disorders (Atkinson et al., 1997, Russo et al., 1997) or that patients with BD had better subjective QOL compared with SCZ patients (Chand et al., 2004, Latalova et al., 2011). Studies using the World Health Organization Quality of Life Assessment — Brief Form (WHOQOL-BREF) to measure QOL have found that both remitted patients with SCZ and BD reported similar levels of QOL (Yen et al., 2008). Brissos et al. (2008) had similar findings, with the exception of psychological domain, in which bipolar patients reported significantly lower QOL compared to schizophrenia patients. However, Latalova et al. (2011), using another tool, the Quality of Life Enjoyment and Satisfaction Questionnaire, to measure QOL, found that remitted SCZ patients had significantly poorer QOL than remitted BD patients. The QOL of individuals with mental illness has been found to be associated with clinical measures, including severity of psychopathology (Brissos et al., 2008, Cotton et al., 2010), and level of psychosocial functioning (Cotton et al., 2010, Woon et al., 2010). Both SCZ and BD patients with more severe psychopathology measured using the Positive and Negative Syndrome Scale (PANSS) were found to report lower QOL (Brissos et al., 2008, Cotton et al., 2010).

In this study, to extend previous findings, we aimed to compare QOL between remitted and unremitted patients with SCZ and BD; as well as determine the clinical predictors of poorer QOL in the patient group. Based on extant data, we hypothesized that there would be comparable QOL between remitted patients with SCZ and BD; and that greater severity of psychotic symptoms, and worse level of psychosocial functioning would predict worse QOL in both patient groups.