Objective: A problem in psychotherapy is the limited availability of psychotherapists. This can not only delay the start of therapy but also curtail the number of sessions and the therapeutic dosage. An option to extend the therapeutic dose without an increase in therapist time may be to combine group psychotherapy with a self-help group. The goal of the present study is to investigate how patients judge this treatment mode and to what degree the contents of a regular group treatment are pursued in a parallel self-help group. Method: Seventy-two psychosomatic inpatients participated in cognitive behavior group therapy and parallel self-help group, which was monitored by the therapist during the regular group therapy sessions. Patients in both groups filled in a questionnaire that asked for the content of the group session, how patients had experienced the interaction, and what they had taken from the group. Results: Patients reported that in the self-help group, they discussed similar topics as in the regular group therapy, like how to deal with anxiety or sadness, how to interact with other people, and how to cope with their mental disorder and problems at work, in the family, or with friends. Patients indicated that there was more relaxed chatting in the self-help group, whereas learning new behavior was reported more frequently for the regular group therapy. Conclusions: In the regular group therapy and the guided self-help group, similar topics were discussed, which suggests that a combination of both can extend the therapeutic process and increase the therapeutic dosage without costs for the therapist or the institution.