Wikipedia is a great place to start your research if you don't know much about your topic, but it should not be the last stop in your research journey.
Scroll down to the References and External Links at the bottom of the Wikipedia entry. They should include sources like books, online articles, reports, and data sources.
If the Wikipedia entry does not include References and the External Links are dead, assume the information on the page is unreliable and/or out-of-date and move on to a better source.
Do not include Wikipedia in your list of references or works cited. But DO use it for excellent background information on gun violence, opioid use, and mental illness.