title: Massed versus spaced sessions in systematic desensitization.
mesh_terms: D001521:Behavior Therapy; D005239:Fear; D005260:Female; D006801:Humans; D010698:Phobic Disorders / Q000628:therapy*; D011615:Psychotherapy, Group; D012063:Relaxation; D013112:Spiders; D013997:Time Factors