Cross-cultural adaptation of the Schizophrenia Caregiver Questionnaire (SCQ) and the Caregiver Global Impression (CaGI) Scales in 11 languages

Schizophrenia is a severe mental illness affecting 0.3-0.7 % of the population worldwide [1], characterized by three domains of psychopathology, including negative symptoms (social withdrawal, lack of motivation and emotional reactivity), positive symptoms (hallucinations, delusions) and cognitive deficits (working memory, attention executive function) [2]. It is considered a leading cause of disability [3].

With the transition in care from formal hospital based healthcare systems to outpatient and community services and informal caregivers, it is estimated that 50-90 % of people with chronic psychiatric illness live with their families or friends [4, 5]. Informal caregivers (defined as “a person who has significant responsibility for managing the well-being of a person diagnosed with schizophrenia in an unpaid capacity” [6]) provide an important service by reducing the need for formal care and the burden upon healthcare systems [7].

The Schizophrenia Caregiver Questionnaire (SCQ) was developed to provide a comprehensive view of caregivers’ subjective experiences of the impacts of caring for someone with schizophrenia [8]. It was adapted from the Zarit Burden Interview (ZBI) [9] in accordance with best practice recommendations for the development and modification of self-report measures [10]. The ZBI was originally developed to measure subjective burden among caregivers of adults with dementia. Items were generated based on clinical experience with caregivers and prior studies resulting in a 22-item self-report inventory that examines burden associated with functional/behavioural impairments and the home care situation. Based on findings from the literature, review of the ZBI, expert opinion, and face-to-face, semi-structured interviews with 19 US English speaking caregivers [11], changes were made to address concerns regarding relevance and sensitivity of the ZBI in the population of caregivers of patients with schizophrenia. The main changes consisted in the rewording of some items, the development of eleven additional items focusing on issues important to caregivers, the deletion of one item (i.e., item 9 of the ZBI - Do you feel strained when you are around your relative?), and the addition of a recall period (i.e., the past four weeks). In addition, the 5-point Likert-type response scale was replaced by an 11-point numerical rating scale (0–10 NRS). This change was decided with the hope that this modified response scale would allow more subtle changes to be captured by the questionnaire. The version of the SCQ that underwent cultural adaptation was a 32-item version, which was also the one that underwent psychometric validation.

The final version of the SCQ (after psychometric validation) is composed of 30 items covering 9 domains including: humanistic impact, exhaustion with caregiving role, lack of support, patient dependence, worries for the patient, perception of the care provided, financial dependence of the patient, financial impact of caregiving, overall difficulty of caregiving role.

In addition, a series of Caregiver Global Impression (CaGI) scales were also developed. These were designed for completion by caregivers to assess their perception of the severity of the schizophrenia symptoms of the person they care for over the past four weeks [“Please rate the severity of his/her symptoms during the past 4 weeks” scored “no symptoms” (0) to “very severe symptoms” (5)]; change in the schizophrenia symptoms of the person they care for since the beginning of the study [“Overall, how have his/her symptoms changed (if at all) since the beginning of the study (before starting treatment)?” scored from “very much improved” (1) to “very much worse” (7)]; and change in the experience of caring since the beginning of the study [“Overall, how much have your experiences of caring for a person with schizophrenia changed (if at all) since the beginning of the study (before the person started treatment)?” scored from “very much improved” (1) to “very much worse” (7)].

As for other conditions, clinical research in schizophrenia has become global [12]. In this context, outcome assessment has to be done in a multi-cultural framework; questionnaires need to be available in various languages to be included in multinational clinical trials and they need to appropriately capture the experience of individuals (patients or caregivers) with different linguistic and cultural backgrounds. Guidance for developing translations which are linguistically and culturally sound and respect the content validity of the original version has been developed by several organizations [13, 14]. In parallel, the Food and Drug Administration (FDA) requires that evidence about similarity of content validity and other measurement properties between the translated questionnaires and the original version be provided [10].

The objectives of the study were to prepare the SCQ and CaGI for use in a multicultural clinical research setting by conducting a proper translation of these instruments originally developed in US English in 11 languages, to present evidence that the translations capture the concepts of the original questionnaires and are well understood by caregivers of patients with schizophrenia in each target country. The translation of the SCQ was carried out on the instrument prior its psychometric validation (i.e., 32-item version).

The results of the linguistic validation process indicate that the translations of the SCQ and the CaGI scales into 11 European languages adequately captured the concepts of the original English-language version of the questionnaires and were easily understood by caregivers of patients with schizophrenia. For each translation, it was important to utilize everyday language, yet remain true to the original meaning of the items. This involved focusing on semantics and required extensive discussion about the meaning of each concept and the adequate word to be chosen to convey it. This was accomplished through steady and continual discussion between the local team of translators, the local team leader, the central project manager and the developers of the original questionnaires. The initial conceptual analysis was crucial to obtaining translations harmonized with each other and faithful to the meaning of the original. The participation of caregivers of patients with schizophrenia greatly improved the initial translations, and provided input essential to the development of versions easily understood by the target population. In most cases, the solutions to each difficulty were decided collegially. Each decision was documented to enable further discussion at the time of the psychometric testing of the translations. The involvement of the caregivers in the development of the original version of the SCQ and its translations was essential. This is in the line with recent reviews which stress the need for tools with relevant content based on caregivers’ views [18, 19].

Cross-cultural equivalence is a critical factor/an essential component for instruments used in multi-cultural studies. Demonstrating cross-cultural equivalence entails investigating that the instrument measures the same concepts in a similar way across the different languages and cultures [20, 21]. It facilitates the pooling of data collected by the different languages versions of the instrument, and in the context of clinical trials, it optimizes the chance of demonstrating treatment benefit by improving the quality of measurement of the outcomes of interest [22]. Applying proper linguistic validation methodology contributes to the achievement of cross-culturally equivalent versions of instruments by optimizing the different languages versions. In addition, this process can generate useful data to document cross-cultural equivalence. During the linguistic validation of the SCQ and CaGI scales in 11 languages, no major cultural issues emerged. This shows that the concepts that were identified in the development of the original US English version of the questionnaire were relevant to the caregivers in other countries, supporting the existence of an overall common experience of the caregivers of patients with schizophrenia in a range of countries. This finding is important, given the recognized importance of cultural aspects in schizophrenia [23].

We have identified several limitations to our research: first, the use of a convenience sample (not representative of the entire population of caregivers of patients with schizophrenia), and the use of telephone interviews for some languages [French for Canada (n = 5); English for Canada (n = 5), Finnish (n = 2); Dutch (n = 1) and English for Australia (n = 1)], which may have prevented the interviewer to capture all the subtleties of body language during the completion of the questionnaire, and finally the fact that this research was conducted in Western countries only. It would be of great interest to extend this cross-cultural research on the experience of caregivers of patients with schizophrenia in a wider spectrum of countries and cultures. A recent review has shown that sociocultural and ethnic characteristics play an important role in the perception of family caregivers’ burden [24]. However, published research on cross-cultural perspectives in caring for someone with schizophrenia is still limited. A PubMed search with key words such as “schizophrenia,” “cross-cultural” and “caregiver” showed that publications in this area represent only 4 % (n = 38) of the papers published in schizophrenia and cross-cultural research (n = 942). Most of the studies operate within one continent [25‐27] or within relatively similar cultural settings (i.e., Chinese-speaking countries) [28]. Very few compare populations such as ethnic groups within one country [29, 30] or caregivers from very different geographical areas or levels of development [31]. In a study comparing the health-related quality of life of French and Chilean caregivers, Boyer et al. [31] use a generic questionnaire (i.e., the SF-36) and show similar levels of health-related quality of life.

The availability in 11 European languages of disease-specific questionnaires such as the SCQ and the CaGI scales to assess the impact of caring for patients with schizophrenia is the first step to wider development and use in various cultural settings. International studies assessing differences of impact across cultures would be of great interest. They would enable cross-cultural comparisons, improve awareness, tracking, and management of impact on caregivers of patients with schizophrenia in different cultures, thus providing opportunity for increased support.

Translations of the Schizophrenia Caregiver Questionnaire and the Caregiver Global Impression scales into 11 languages adequately captured the concepts in the original English version of the questionnaires, thereby demonstrating the conceptual, semantic, and cultural equivalence of each translation.

After psychometric testing, the instruments will be available for use in clinical trials facilitating international comparison and pooling of data and will provide new insights into the area of caregiving of schizophrenia.