Differential Loneliness Scale.
The differential loneliness scale is a 20 item questionnaire.
T (True) is given 1 point if it does not have an asterisk next to the item number. F (False) is given 1 point if it does have an asterisk next to the item.
The scale measures loneliness in four types of relationships, romantic/sexual relationships (R/S), friendships (Fr), relationships with family (Fam), and relationships with larger groups (Gr).
Schmidt, N. & Sermat, V. (1983). Measuring loneliness in different relationships. Journal of Personality and Social Psychology, 44, 1038-1047.