Quality of life is predictive of relapse in schizophrenia

Schizophrenia is a severe and chronic mental illness that is characterized by recurrent relapses [1, 2]. Relapse is disabling and distressing for the individual with schizophrenia and is associated with a progressive functional deterioration as well as worsening treatment response and clinical prognosis [3]. Moreover, relapse increases caregiver burden [4] and represents a significant economic burden on families and society [5, 6]. Because the prevention of relapse is a major challenge in the care of patients with schizophrenia, numerous studies have investigated the value of socio-demographic, clinical, and medication factors in the prediction of relapse [1, 2, 5, 7‐9]. However, although these reports have provided a better understanding of factors that influence the course of schizophrenia, these factors imperfectly predict relapse, and the relapse rate still remains high. Other factors, such as social and environmental factors known to influence the course of schizophrenia [10, 11], have received scant attention. A more thorough and comprehensive understanding of these factors is necessary. On the other hand, Quality of Life (QoL), which is defined as a subjective evaluation embedded in a cultural, social, and environmental context [12], has gained increasing acceptance in psychiatric research along with the traditional assessments of clinical outcomes. Recent studies have shown QoL to be an independent prognostic factor associated with clinical outcome in various chronic diseases including oncology, often predicting survival or occurrence of hospitalization [13‐17]. However, two studies have shown that QoL scores added relatively little to socio-demographic, clinical, and medication factors in the prediction of relapse in schizophrenia [1, 5]. Because the median time to relapse following a previous remission in schizophrenia has been estimated to occur at the end of the first year [18, 19], the relatively short follow-up period of these two studies (6 and 12 months) may have underestimated the rate of relapse. To date, no study has assessed whether QoL provides prognostic information in addition to conventional socio-demographic, clinical, and medication factors for patients with schizophrenia after a sufficient follow-up. The objective of this study was to evaluate whether baseline QoL, as measured by the SF36 and the QoLI, is predictive of relapse for patients with schizophrenia over a 24-month follow-up.

Of the 1,208 patients in the EuroSC, 184 patients were excluded from the analysis because they did not have any follow-up data (15%). A total of 1,024 patients (85%) were then included in the present analysis. There were no statistical differences between the 1,024 patients in the study group and those 184 who were excluded in terms of age, gender, living condition, functioning (GAF score), antipsychotic medication, SAS, BAS AIMS, and QoL scores at baseline (all p-values > 0.05). On the contrary, in comparison to included patients, excluded patients had a slightly higher severity of symptoms (respectively 56.5 (20.2) vs. 64.3 (24.9), p = 0.001 for the total PANSS score) and lower compliance scores (respectively 11.0 (3.3) vs. 11.5 (3.1), p = 0.043 for the ROMI compliance score).

Using data from the observational EuroSC cohort, we examined the predictive value of QoL with respect to relapse. Our study examined 1,024 patients with schizophrenia; controlled for important socio-demographic, clinical, and medication factors; and has attempted to overcome the limitations of past studies by using a large sample size and a 24-month follow-up, which enables a more complete analysis of full relapse. The findings provide evidence in support of a relationship between QoL scores and relapse in this patient population.

QoL, as assessed by a generic instrument (SF36), is an independent predictor of relapse in schizophrenia. This finding is consistent with a 12-month follow-up study using the SF36, in which a higher level of QoL predicted a moderately lower rate of relapse at 12 months (OR = 0.98 for both the Physical and Mental Composite Scores) [1]. Surprisingly, this relationship was not confirmed in our study using the QoLI, which only presented a trend (p = 0.083). Again, this finding is consistent with a 6-month follow-up study using the QoLi, in which relapsed patients appeared to experience a lower QoL than non-relapsed patients at baseline, but the differences were not statistically significant [5]. The fact that a generic instrument like the SF36 better predicts relapse than a specific instrument like QoLI may appear paradoxical. The use of QoL-specific instruments is generally recommended in schizophrenia because they identify the specific needs of patients and are more sensitive to change and treatment/intervention effects than are generic instruments [32]. However, the QoLI is designed to encompass a broad range of mental illnesses, not specifically schizophrenia. According to Cramer et al. [32], the QoLI showed less sensitivity to change and treatment effect than did schizophrenia specific QoL instruments. A previous study has also shown that a better agreement was observed between the SF36 and schizophrenia specific QoL instruments than with the QoLI and that the SF-36 was more strongly correlated with clinical status than the QoLI [33].

An important finding in our study concerns the SF36-PCS, which was a stronger relapse predictor compared to the SF36-MCS. This finding confirms the need for clinicians to increase their attention on the physical health of patients with schizophrenia [34]. Although most patients view their physical health as a high priority, many clinicians consider their primary function to be the management of mental and psychological health [35]. The subjective physical well-being of patients with schizophrenia should thus be considered by clinicians as an important predictor of relapse, in the same way that psychological aspects are considered.

In our study, unlike previous studies [5, 7, 19, 36], a more severe symptomatology was not associated with relapse, and other factors such as functioning or compliance were only moderately associated with relapse. One possible explanation for this discrepancy might be that QoL, which was not taken into account as a potential predictor in previous studies, may have a confounding influence on the relationship between traditional predictors and relapse. On the other hand, the exclusion of more severe and less compliant patients (15% of the cohort) may have also attenuated the predictor strength of symptomatology and compliance. Beyond these explanations, it is interesting to note that, although the predictive value of the different factors was moderate in our study, QoL was a stronger predictor than clinical information.

Finally, our findings can also be interpreted in terms of the recovery process. The concept of recovery is broadly organised into 2 types: clinical objective (i.e. clinical symptoms and functioning) and personal subjective including in particular QoL among other domains such as personal confidence and hope, willingness to ask for help [37, 38]. Our findings suggest that personal subjective recovery (i.e. QoL in our study) is more predictive of relapse than objective recovery. These findings should however be confirmed on other domains of subjective recovery. On the other hand, these results should be considered to improve the characterisation and treatment of patients with schizophrenia. Our findings may support the development and monitoring of complementary therapeutic approaches, such as ‘recovery-oriented’ combined with traditional mental health cares to prevent relapse. Interestingly, QoL has been linked to metacognitive capacities in recent studies [39, 40], suggesting that interventions targeting metacognition, such as psychotherapy, may play a key role in preventing relapse [41].

This study shows that QoL measures can be considered as an independent predictor of relapse in schizophrenia. This finding may have implications for the future use of QoL in psychiatry. To date, QoL remains largely under-utilized in clinical practice [47]. Several studies have reported that clinicians believe that QoL measures lack clinical relevance for their patients [48, 49]. More work must be done to convince clinicians of the clinical relevance of QoL instruments in order to enhance the use of QoL measures in clinical decision-making [50]. Our findings, similar to those in other studies, especially in oncology, provide strong support for the integration of QoL into clinical practice along with other standard assessments in psychiatry.