Three weeks of taking fluoxetine

After three weeks of taking fluoxetine, a college student was reported by her roommate to have been acting strangely for a week. She began staying up all night working on projects that were not required of her classes and despite getting only 2-3hours of sleep per night, feeling rested. She had been speaking excitedly and kept referring to a top secret study involving the ISI. She shifted from excited, agitated expressions to tearful exasperation. She reported never having felt this way before and said that she had been taking the fluoxetine as instructed. The diagnosis at this time is:

A. Schizoaffective disorder
B. Bipolar Disorder
C. Schizophrenia
D. Substance-induced mood disorder

Ans: D, Substance-induced mood disorder. Currently this presentation is of an apparent fluoxetine induced manic episode.
A is incorrect, the patient would have to have had an episode of psychotic symptoms in the absence of depressive or manic episode in order to be diagnosed with schizoaffective disorder
B is incorrect; this patient may later be diagnosed with bipolar disorder but not at this time
C is incorrect, while the psychotic symptoms that are present could be the onset of schizophrenia, the manic symptoms would generally not be present. Symptoms must also have been present for at least 6months to meet criteria for schizophrenia.
Chapter 10, Textbook of Clinical Psychiatry