100% if your not in a good place i recommend not doing it....but on the inverse it can actually make you process it all real quick...i have watched friends who have done in a bad mental state and watched them process  5years of stress and hurt in 10mins on DMT...so really its all in the hands of the person using it. I recommend watching a movie called "Spirit Molecule" amazing film captures the essence of DMT really well. 
good questions to man :)