New research shows people find antidepressants to be more addictive than they're told.

The study in the International Journal of Mental Health Nursing claims the drugs are over-prescribed, and not all patients are being told they might find it hard to come off.

Study co-author, Auckland University associate professor Claire Cartwright says the drugs aren't addictive in the medical sense, but people still feel dependent.

"If you're a person, you've been on antidepressants for three years, you decide to come off them, you take it slowly then you have these symptoms that you feel you can't control, perhaps that's what leads people to say they feel addicted," she said.

The study shows that 55 percent of the 1800 New Zealanders surveyed had withdrawal effects after stopping their meds.

But Cartwright says just one in a hundred patients remembers being told about the side effect.

"If it's spoken about, sometimes people say there'll be withdrawal symptoms for one or two weeks but the majority of people said no they haven't been told."