What is the most likely diagnosis for a patient who experiences an expansive mood and engages in excessive cleaning without sleeping?

The diagnosis of bipolar disorder is supported by the symptoms described in the scenario. Characterized by mood episodes that can significantly fluctuate, bipolar disorder includes manic or hypomanic episodes where individuals may experience an expansive mood, increased energy, and impulsive behaviors. The excessive cleaning indicates heightened activity, which is a common feature of the manic phase. Additionally, the mention of insomnia or lack of sleep further reinforces the possibility of a manic episode, as individuals during this phase often require less sleep while feeling energized.

Major depressive disorder is primarily focused on depressive symptoms and does not usually include the expansive mood or the hyperactive behaviors associated with mania. Generalized anxiety disorder primarily involves excessive worry and does not typically present with mood elevation or impulsive actions. Schizophrenia involves psychotic symptoms such as delusions or hallucinations, which are absent in this case.

Thus, the combination of an expansive mood, excessive cleaning, and lack of sleep strongly aligns with the characteristics of bipolar disorder, making it the most likely diagnosis.