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: The association between psychiatric co - morbidity and methamphetamine - induced psychosis was also studied .
### Output Text:
The association between psychiatric co - morbidity and <span class="chemical">methamphetamine</span> - induced psychosis was also studied . 