Who says vitamins, proper diet and exercise won't work to relieve depression and/or other "mental disorders"? 
I'm recovering from several years of damage from a variety of SSRIs, benzos and a tricyclic. 
I had most of the listed side effects from each drug, plus horrific withdrawal effects from discontinuing the drugs too quickly. Doctors are taking patients off of these drugs too fast, causing withdrawal problems, sometimes severe. But that's another story. My two original diagnoses, depression and anxiety, are gone now because of vitamins, proper diet (whole foods, no artificial flavorings/colors, etc.) and gentle exercise. I'm left only with drug-induced problems, such as depersonalization, numbness and burning sensations in the extremities, weakness and insomnia. And even those problems are waning because I'm taking proper care of myself now. You might say that those symptoms are signs of mental illness, but I assure you they didn't show up until after I'd been on drugs for some time. Some were the result of discontinuing. 
I want to add that I'm not a fan of Tom Cruise, nor am I a scientologist. But he was definitely telling the truth.