Answer:
The placebo effect is used to assess the efficiency of medical drugs in clinical trials, it is calculated as the difference between the response to a placebo stimulus and no treatment.
Group therapy is used to treat a wide range of mental disorders, typically anxiety problems, problems for socialization and communicational issues. Group therapy is useful 1-to improve communication and socialization skills, 2-to learn how to express own ideas 3- to accept constructive critic, and 4-to develop empathy skills by listening the experiences of others.
According to Freud, the resistance refers to the patient's defensive efforts to fight against with the vision of an external source. Effective treatment of the resistance feeling can be useful to eliminate anxiety, depression and similar mental disorders.