Multiple domains have been suggested to comprise social support, including structural support (e.g. types of support networks) and functional support. Functional support is usually organized along four dimensions: instrumental, informational, belonging and emotional support. In the present study, the presence or absence of confidants and the satisfaction level with the confidants were evaluated as factors reflecting functional social support.(22,23) The psychiatrists asked the patients whether they had confided in someone or discussed their cancer with anyone during the period between the cancer diagnosis and 1 month after surgery and, if so, how many people they had confided in. Categories of confidants, such as spouse, children, parents, siblings, friends, neighbors, colleagues, physicians, nurses, priests or others, were suggested as examples to help the participants to answer the question. Finally, patients were asked how satisfied they were, overall, with their interactions with these confidants. If they had not confided in anyone, they were asked about their degree of satisfaction with that situation. The patients’ responses were categorized on a scale of 1–7:1, extremely dissatisfied; 2, fairly dissatisfied; 3, slightly dissatisfied; 4, neutral; 5, somewhat satisfied; 6, fairly satisfied; and 7, extremely satisfied. The reliability of the interview ratings with regard to social support was determined by conducting a second interview at 3 months after surgery in the same cohort. The interview ratings at 1 month and 3 months after surgery with regard to the presence or absence of confidants, the number of confidants, and the level of satisfaction with the confidants were compared. The inter-rater agreement (kappa) with regard to the presence or absence of confidants was 0.518 (P < 0.001) at 1 month and 3 months after surgery. The correlation coefficient for the number of confidants at 1 month and 3 months after surgery was 0.714 (P < 0.001). The correlation coefficient for the level of satisfaction with confidants was 0.482 (P < 0.001) at 1 month and 3 months after surgery. The interview ratings with regard to social support status indicated moderate consistency between 1 month and 3 months after surgery. The validity of the interview ratings was determined by comparing the responses to the Social Support Questionnaire (SSQ)(24,25) of a random sample of 41 patients with various cancers. The SSQ was used to quantify the availability of and level of satisfaction with social support. We used an abbreviated six-item version, each item consisting of two parts. The first part assessed the number of individuals that the patient felt they could turn to in times of need (SSQ number; SSQN), and the second part measured the individual's perceived degree of satisfaction with the support available in that particular situation (SSQ satisfaction; SSQS). Thus, both the number of confidants and the level of satisfaction with the confidants were assessed by the SSQN and SSQS, respectively. In the present study, we used the subscales of SSQ question no. 1 (‘Who can you really count on to be dependable when you need help?’) for validity of the interview ratings, because this question was similar to our question. The correlation coefficient was 0.687 (P < 0.001) for the number of confidants and the score of the SSQN question no. 1. The correlation coefficient was 0.317 (P = 0.044) for the level of satisfaction with confidants and the score of the SSQS question no. 1. The interview ratings with regard to social support showed a moderate degree of consistency with the score of the SSQN question no. 1 and SSQS question no. 1.