The Differential Loneliness Scale was presented to 30 persons in a mental growth group (test group) and to 36 adult students of psychology (controls). The majority of the subjects were aged 19 to 25 yr. The test group experienced loneliness statistically significantly more than the controls. The test group would be classified as lonely also according to American norms for the scale and for the UCLA test. There were no statistically significant differences in experiencing loneliness between men and women. Ten factors were extracted by Varimax rotation: Support from others, quality of friendship relations, group affiliation, number of friends, dependence on others, love relations, family relations, receiving understanding, reliance, and expressing emotions. The test group experienced their love relations and family relations, understanding from others, and the quality of friendship relations statistically significantly as less satisfactory than the control group. Concurrent validity for the UCLA test was satisfactory (.70) in spite of the different structure of these loneliness scales. Cross-validation is required.