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DSM-IV mental disorders
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CIDI 3.0 [45–47] |
| DSM-IV mood disorder (major depression, dysthymia, bipolar disorder), anxiety disorder (panic disorder, agoraphobia (without panic disorder), social phobia, specific phobia, generalised anxiety disorder) and substance use disorder (alcohol/drug abuse and dependence). Prevalence was defined as the presence of the mental disorder in the 12 months prior to the T0. First-incident cases of a category of disorders were defined as persons who developed a disorder in a category (mood, anxiety or substance use disorder) between T0 and T1, among those who had never experienced any separate disorder in that category at T0. For first time incidence in the category ‘mood disorder’ only those subjects who did not have a lifetime mood disorder before T0, were included in the ‘at risk’ group for this category at T1. Therefore, the number of respondents 'at risk' varied per group. Incidence was calculated for each separate disorder. |
The interviews were conducted by professional, experienced interviewers. Clinical calibration studies conducted in various countries have found that CIDI 3.0 [40] and earlier versions [48, 49] assess anxiety, mood and substance use disorders with generally good validity compared to blinded clinical reappraisal interviews. At T0, a lifetime CIDI version was used. At T1 a CIDI version with a timeframe of the period between T0 and T1 was used. |
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Explained physical symptoms
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| Respiratory disorders (asthma, chronic obstructive pulmonary disease, chronic bronchitis, emphysema), cardiovascular disorders (severe heart disease, heart attack, hypertension, stroke), stomach or intestinal ulcers, severe intestinal symptoms (only if an explanation about the cause was given such as pancreatitis, hernia abdominalis), diabetes, thyroid disorder, chronic back pain (only if an explanation about the cause was given such as neck hernia, paraplegia, caused by accident), arthritis, migraine, cancer, impaired vision or hearing. |
Interview based on questionnaire of physical symptoms, in which the main physical symptoms of the CBS questionnaire can be found [50]. These physical symptoms were based on self-report by the subjects during the interview, and not by medical records [47]. Comparisons between self-reports of chronic physical disorders and medical records show moderate to good concordance [51–53]. Subjects were considered to have PHY at T0 if they reported to have been treated or monitored by a physician in the 12 months prior to T0 for one or more of the disorders, and after confirmation by two physicians, in duplicate, if symptoms should be considered to be medically explained. |
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Medically unexplained physical symptoms
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| Subjects were considered to have MUS at T0 if their condition applied to both criteria mentioned below: |
Interview based on questionnaire of physical symptoms. |
| 1.Presence of the following physical symptoms, experienced in the past 12 months, for which the subjects indicated that they visited a physician or received medication: |
All physical symptoms mentioned here (verbatim responses) were checked independently by two physicians (JES and CFC) to indicate whether or not they could be considered medically unexplained physical symptoms in general. If their judgments were not the same, they deliberated until consensus was achieved. |
| a) Disturbing intestinal symptoms, existing longer than 3 months, for which no indication of an explanation existed[54]. |
We checked the answers on the open questions to see if an explanation was given about the intestinal symptoms, such as pancreatitis or hernia abdominalis, or the back problem, such as neck hernia or paraplegia. |
| b) Back problems existing longer than 3 months, for which no indication of an explanation existed [55]. |
If this was the case, we did not include the subject in the unexplained group, but in the explained group. |
| c) Other illness or physical symptoms that are long lasting (open question) and unexplained: |
Examples of general symptoms that we considered to be medically unexplained physical symptoms are fibromyalgia, fatigue (such as chronic fatigue syndrome), pain without medical explanation (such as stress related pain in muscles), and physical symptoms accompanied with phrases such as ‘they can’t find anything’ or ‘if only I knew’. |
| 2. Presence of limited functioning reported in the past 4 weeks, as indicated by two or more of the following scales of the SF-36 |
Interview based on SF36: subscales: |
| a) Physical functioning: some or severe limitations in at least one of the ten items in this category |
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| b) Physical role functioning: any limitation reported in at least one of the four items in this category |
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| c) Bodily pain: pain leading to any limitation in normal work activities |
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| d) General health: describes mental or physical health as poor, and/or negative expectations about one's health |
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