Since Schizoaffective Disorder and Bipolar Disorder share some overlapping symptoms, when a patient presents with symptoms similar to both Schizoaffective Disorder and Bipolar Disorder, it becomes necessary to provide continuous and careful care while simultaneously reviewing all knowledge about both disorders. The objective of this work is to address the pre-diagnosis phase, the moment of diagnosis, and the post-diagnosis phase of a patient initially diagnosed with Schizoaffective Disorder who, after years of various treatments until finding the most appropriate one, was diagnosed with Bipolar Disorder Type I. The methodology used for this work was bibliographic research in databases such as SciELO, PubMed, Google Scholar, etc., using the descriptors: schizoaffective disorder, bipolar disorder, childhood mental health, and psychoactive drugs. This entire process lasted approximately six months, during which around 20 publications addressing the chosen descriptors were analyzed, resulting in the selection of 14 articles or scientific papers. The results of this analysis demonstrated that the process of observing symptoms to arrive at a diagnosis and then the treatment process does not reside solely in the current aspects presented by the patient during initial consultations, but also in the patient’s past history. This is because there are often previous problems that can affect the diagnosis and the treatment process, which is frequently observed in cases of overlapping symptoms, for example.