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: Such medication - associated changes in the total power of pupillary oscillation might be of utility in identifying persons at risk for manic - like adverse effects during the medical use of psychomotor stimulants or sympathomimetic agents .
### Output Text:
Such medication - associated changes in the total power of pupillary oscillation might be of utility in identifying persons at risk for manic - like adverse effects during the medical use of psychomotor stimulants or sympathomimetic agents . 