How many close friends and relatives do you have with whom you feel at ease and can discuss private matters? How many of them do you see at least once a month? Do you participate in any groups? These are among the questions on a survey called the Berkman-Syme Social Network Index, which physicians use to determine whether someone is “socially isolated.” People are considered isolated if they have fewer than six confidants, no spouse and no group affiliations. Those conditions make them less likely to report that they have someone they can count on to listen if they need to talk, give advice about a problem or show them love and affection.