There can be many different responses to starting therapy. As many responses as individuals who are doing the starting. However there are also patterns, or similar ways of responding that can be loosely formed into a theory.
One common response is that I begin to “feel” more. And if what I am feeling is painful, that might lead to an idea that I am actually feeling worse. However it might not be “worse” but different.
Mental distress such as depression and anxiety that often lead someone into therapy can be understood as a symptom of something that the person seeking therapy is not aware of. This something may be a belief (such as I should be strong), a feeling that is blocked, an action (such as tensing the body in order to stop a feeling emerging) or a behaviour.
Working with a psychotherapist, it is possible that I can begin to understand and experience what might be out of my awareness and how I am keeping this out of my awareness. For example; how a feeling is being blocked (usually by some tensing in the body) or a belief not attended to and how this is influencing my present experience.
This process of gaining awareness can take time and requires support as often this “keeping something out of awareness” has been a way to psychologically survive difficult and traumatic experiences.