In addition to Cochrane:
JSTOR academic journal access during Covid-19Scott Alexander Siskind has recently started writing about psychiatric conditions and treatments
Lorien Psychiatry
Welcome to Lorien Psychiatry. We're three things: first and foremost, a working psychiatry practice trying to help patients get better. an online database of mental-health-related resources. This is still under construction. a political/economic experiment. Everyone knows the US health care system isn't working. We want to try something else.
lorienpsych.com
Rob Wiblin listed these (hence the Australian picks : ) I'd be very happy to add to it if there are additional suggestions.
Crazy Meds for mental health treatment: http://www.crazy-meds.org/
UpToDate for treating diseases: http://uptodate.com/ [also suggested by Jim Babcock]
Therapeutic Guidelines for treating diseases: https://www.tg.org.au/
Red Book for screening for disease: https://www.racgp.org.au/.../goodpractice/20171-2/red-book/