In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Apparent risk factors for the development of mania or hypomania during fluoxetine pharmacotherapy in this population were the combination of attention - deficit hyperactivity disorder and affective instability ; major depression with psychotic features ; a family history of affective disorder , especially bipolar disorder ; and a diagnosis of bipolar disorder .
### Output Text:
Apparent risk factors for the development of mania or hypomania during <span class="chemical">fluoxetine</span> pharmacotherapy in this population were the combination of attention - deficit hyperactivity disorder and affective instability ; major depression with psychotic features ; a family history of affective disorder , especially bipolar disorder ; and a diagnosis of bipolar disorder . 