This research project has the overall objective to investigate the direction of the associations between illness perceptions, their influencing factors and health-related outcomes. Moreover, the investigators want to look at the direction of the associations between illness perceptions and health related outcomes such as psychological and physical functioning in patients with Systemic Lupus Erythematosus (SLE) and Systemic Sclerosis (SSc). The investigators want to know whether the outcome variables anxiety, depression, physical (dis) functioning are influenced by illness perceptions or vice versa. Not only the patients' illness perceptions but also the illness perceptions of the General Practitioners (GP) and rheumatologists will be investigated. The researchers want to know if the doctors' perceptions have an impact on the physical and psychological functioning of the patient or vice versa. Much research in the field of illness perceptions is cross-sectional in nature which means that the direction of the relationships between variables is not known.

This is a single center academic study at two timepoints with an interval of 12 months. The data collection includes demographic variables, patient-reported variables, clinical variables and healthcare professionals-reported variables. All SSc and SLE patients who meet the inclusion criteria and are monitored by the rheumatology consultation in the University Hospitals Leuven will be contacted to participate in the study. Patients will be informed of the purpose of the study and what is expected of them. If they agree to participate they will also be asked to sign the Informed Consent form to send together with the completed questionnaire by mail.

After the patient gives his/her agreement to participate his/ her GP and rheumatologist will be asked to fill out the Revised Illness Perception Questionnaire for Healthcare Professionals (IPQ-R HP). This is a questionnaire that measures the perception of the doctor about the disease condition of their patient.

Data will be collected and kept by the investigator for analysis after complete coding. The obtained data will be analyzed using statistical methods.

With this study the investigators want to give an answer on 4 research questions:

1. Are there differences in perceptions between GP's and rheumatologists?
2. What is the direction of the associations between the illness perceptions of the physicians and patients?
3. What is the direction of the associations between the illness perceptions of a patient with SLE or SSc and psychological and physical functioning?
4. What is the direction of the associations between the illness perceptions of the physician and the psychological and physical functioning of the patient?

Inclusion Criteria:

• Before participation the patient gives informed consent.
• The medical condition of the patient allows him/her to complete a questionnaire
• The patient does not have a severe psychiatric comorbidity
• The patient can complete questionnaires in Dutch

Exclusion Criteria:

• no exclusion criteria

Firstly a list will be created of all patients with lupus and systemic sclerosis who are in follow-up at the reumatology department in UZ Leuven. Afterwards all patients who fulfill the inclusion criteria will be selected. The patients who are included will be informed by mail and they will be asked to participate. When they agree for participating then they will be asked to complete an informed consent form.

Hereafter the general practitioner and rheumatologist will be contacted to complete the IPQ-R HP (an illness perception questionnaire for Healthcare professionals)