Table 2.
Risk factors, mechanisms and outcomes investigated by the SOMACROSS research unit
| Risk factors and mechanisms (assessed via self-report/laboratory test) | ||||||
| Predisposing, triggering and maintaining/aggravating factors | Single constructs | Instrument | Items | Months | ||
| 0 | 6 | 12 | ||||
| Sociodemographic factors | Gender, age, nationality, heights, weights, marital status, migration status, current housing situation, insurance, education, occupational status, | Single items | 19 | X | ||
| Health care utilization | Single items | 3 | X | X | X | |
| SARS-CoV-2 infection and Long-COVID-19 | Single items | 7 | X | X | X | |
| Psychosocial factors | Adverse childhood experiences | Adverse Childhood Experiences Qestionnaire (ACE-D) | 10 | X | ||
| Personality: neuroticism | Big Five Inventory-10 (BFI-10) | 10 | X | |||
| Negative affectivity | Positive and Negative Affectivity Schedule (PANAS) | 20 | X | |||
| Life stressors | Perceived Stress Scale (PSS-10) | 10 | X | |||
| Perceived stigmatization | Single items | 2 | X | |||
| Cognitive-perceptual and emotional mechanisms | Somatosensory amplification | Somatosensory Amplification Scale (SSAS) | 10 | X | X | X |
| Catastrophising | Coping Strategies Questionnaire-Catastrophizing Subscale (CSQ-CAT) | 6 | X | X | X | |
| Treatment expectations | Treatment Expectation Questionnaire (TEX-Q) | 15 | X | X | X | |
| Expectation of symptom severity | Numeric Rating Scale | 1 | X | X | X | |
| Expectation of symptom burden | Numeric Rating Scale | 1 | X | X | X | |
| Expectation of coping with symptoms | Numeric Rating Scale | 1 | X | X | X | |
| Psychological burden related to somatic symptoms or associated health concerns | Somatic Symptom Disorder-B Criteria Scale (SSD-12) | 12 | X | X | X | |
| Illness-related worries | Whiteley-Index Short Version (WI-7) | 7 | X | X | X | |
| Symptom perception | Illness perception questionnaire (B-IPQ) | 8 | X | X | X | |
| Anxiety severity | Generalized Anxiety Disorder-7 (GAD-7) | 7 | X | X | X | |
| Depression severity | Patient Health Questionnaire-9 (PHQ-9) | 9 | X | X | X | |
| Alexithymia | Toronto Alexithymia Scale (TAS-20) | 20 | X | |||
| Emotion regulation | Emotion Regulation Questionnaire (ERQ) | 10 | X | |||
| Behavioural factor | Physical inactivity | International Physical Activity Questionnaire (IPAQ-SF) | 7 | X | X | X |
| Biomedical and treatment-related factors | (Prior) organic disease/comorbidity | Self-Administered Comorbidity Questionnaire (SCQ) | 16 | X | X | X |
| Medication adherence | Medication Adherence Report Scale (MARS-D) | 5 | X | X | X | |
| Treatment side effects | Numeric Rating Scale | 1 | X | X | X | |
| Treatment experiences | Numeric Rating Scales | 2 | X | X | X | |
| Systemic inflammation, markers of central sensitisation (P1–P5) | C reactive protein (CRP), Interleukin-6 (IL-6), Tumour necrosis factor (TNF) | N/A | X | |||
| Duration of disease | Single interview questions | 2 | X | X | ||
| Medication | Single interview question | 1 | X | X | ||
| Outcome variables (assessed via self-report/diagnostic interview) | ||||||
| Primary outcome: somatic symptoms | Somatic symptom burden | Patient Health Questionnaire-15 (PHQ-15) | 15 | X | X | X |
| Symptom intensity | EURONET-SOMA Numeric Rating Scale | 1 | X | X | X | |
| Secondary outcomes | Symptom interference | EURONET-SOMA Numeric Rating Scale | 1 | X | X | X |
| Symptom-related disability | Pain Disability Index-adapted (PDI) | 7 | X | X | X | |
| Health-related quality of life | Short Form Health Survey (SF-12) | 12 | X | X | X | |
| Diagnosis of somatic symptom disorder (DSM-5) | Structured Clinical Interview for the DSM-5 (SCID) | 18 | X | X | ||
| Total (self-report items) | 276 | |||||