The figure shows the progress of patients through the study. Of the 10
161 patients aged 20-45 years in the 10 practices, 1064 patients (10.5%) were frequent attenders without serious disease. The somatisation questionnaire was returned by 714 frequent attenders (67%), of whom 362 (51%) reported five or more somatisation symptoms. Non-respondents (350) were more likely to be unmarried men, living alone, and have psychological problems, particularly addiction to alcohol and hard drugs. Of the 362 patients eligible for the trial, 87 did not answer telephone calls or letters, and 35 declined to participate. We did not contact 79 patients because enough patients had already been enrolled. Accordingly, 161 patients were included in the trial.
Altogether 137 patients completed the trial; 24 patients (15%) dropped out and were not included in the final analyses. Ten patients (five in each group) did not return the baseline questionnaire, and 14 (six in the intervention group and eight in the control group) did not complete the two year follow up. Of these 14, two control patients were admitted to a psychiatric clinic, two died (one control, one intervention), three patients moved with no forwarding address (one intervention, two control), and the remaining seven did not return the two year questionnaire despite several reminders (four intervention, three control).
Of the 81 intervention patients, 77 received the disclosure intervention and completed the two meetings with the disclosure doctor; the remaining four dropped out before receiving the intervention. Twenty two patients participated in an additional joint consultation with their own doctor. Of the remaining 55 patients, 30 did not disclose important information in the two meetings, nine had previously discussed the disclosed information with their doctor, 11 did not want to share the disclosed information with their doctor, and five gave no clear reason why they did not want to participate in the joint consultation.
According to the patients and disclosure doctors, 47 patients disclosed emotionally important information during the intervention. Topics of disclosure were childhood abuse (sexual, physical, or mental), alcohol dependency of parents, and loss of a parent or sibling at young age. Quite often patients reported that they had borne onerous household responsibilities as young children. A range of problems in adulthood was disclosed, including physical or sexual abuse, alcoholism, problems in relationships or at work, and social isolation. Patients commonly disclosed combinations of problems—for example, sexual abuse in childhood and depression in later life with marital problems. According to the DSM-IV screening, 34 of the 77 patients had an active depressive or anxiety disorder (16 a depressive disorder, 30 an anxiety disorder). Two patients fulfilled the criteria for hypochondriasis and 18 for the chronic benign pain syndrome.
At the start of the study, both groups had similar demographic and clinical characteristics (table ). Changes in main outcome measures during two years of follow up were not significantly different between the two groups (table ). Visits to health care increased by one more visit in the disclosure group at 24 months; the use of medicines did not change in either group; subjective health improved 3.6 points more in the control group; and disclosure patients were on sick leave one more week.
Comparison of intervention and control groups at baseline. Values are median (interquartile range) unless stated otherwise
Change in outcome variables between baseline and follow up at two years. Values are medians (interquartile range)
Detailed analyses of visits to specific healthcare professionals and use of different kinds of drugs showed no significant differences (table ). In addition, changes in subsidiary outcome measures (quality of life, symptom check list-90, social support, and doctor's judgment of somatisation) did not differ between the groups (table ). The general pattern was the same at the six and 12 month follow ups (data not shown). We found no significant differences in the subgroup analyses. Neither successful disclosure nor participation in the joint consultation affected the results.
Visits to health care and use of drugs at baseline and two year follow up (n=137)
In general, the disclosure intervention was well received: 57 out of 77 patients judged it positive, and at two years of follow up more intervention than control patients thought participation in the study had changed their health favourably (mean score 51 in intervention patients versus 47 in control patients (scale 0-100), P=0.11). However, at six and 12 months there was no difference between the groups on this measure. One patient criticised the disclosure intervention; she refused to be confronted with her childhood story again.
We did two checks for possible contamination between the two branches of the trial. General practitioners were asked to identify the control patients in their practice from a larger list towards the end of the trial. Fourteen patients (17%) were correctly identified, 21 patients (26%) were falsely identified as intervention patients, and 45 were incorrectly thought to be non-participants (κ=0.08). As a second check, we followed 98 patients in nine practices in which no intervention was introduced (data not presented). These 98 patients showed similar characteristics at baseline to the intervention and control patients, and changes on primary outcome measures at the two year follow up were not significantly different from the intervention and control group. The only difference was that patients in the intervention group were judged by their doctors to somatise less than patients in the external practices at the two year follow up (median score 3 in intervention patients v 3.5 in control patients (scale 1-5), P=0.01).