In a new article, evolutionary biologist Paul Andrews says antidepressants affect the levels of serotonin in the brain. Serotonin regulates mood, but Andrews also notes it is used for other purposes, including digestion, forming blood clots at wound sites, reproduction and development.

"Serotonin is an ancient chemical. It's intimately regulating many different processes, and when you interfere with these things you can expect, from an evolutionary perspective, that it's going to cause some harm," the McMaster University professor said in a release about his paper.

Andrews said antidepressants elevate risks of developmental issues in infants; problems with sexual stimulation and function and sperm development in adults; digestive problems such as diarrhea, constipation, indigestion and bloating; and abnormal bleeding and stroke in the elderly.

"The thing that's been missing in the debates about antidepressants is an overall assessment of all these negative effects relative to their potential beneficial effects," he said in the paper, which was published Tuesday in the journal Frontiers in Psychology.

"Most of this evidence has been out there for years and nobody has been looking at this basic issue."

He said it's important to look critically at using antidepressants.

"You've got a minimal benefit, a laundry list of negative effects - some small, some rare and some not so rare. The issue is: Does the list of negative effects outweigh the minimal benefit?"