Passage Summary: Since your problems come from your relationships with other people, your therapist has to focus on fixing those relationships to get you better.

Conclusion: Psychotherapists must prioritize improving a patient's interpersonal relationships to facilitate healing.

Reasoning: The psychological issues that lead people to seek therapy are caused, at least in part, by their interactions and relationships with others.

Analysis: The therapist is assuming that the 'cure' must match the 'cause.' Just because a problem started because of a bad relationship doesn't strictly mean the only way (or a necessary way) to fix it is by changing that relationship. To find the necessary assumption, ask yourself: 'What if the therapist could heal the patient by focusing solely on internal coping mechanisms instead?' If the argument fails without the requirement to fix relationships, then that requirement is our missing link.