The ex-EastEnders actress revealed that she has faced "dark times" during her life but was brave enough to seek help for the condition.
She told Good Housekeeping: "Life at the moment couldn't be much better, but there have been times and situations in my life when waking up in the morning has not been fun.
"It's no longer a taboo to seek help at dark times, be it from a professional or a friend, and I did that when I was younger."
Outhwaite went on to say that her former struggles have made her appreciate the good things in her life even more.
"It helped me realise what's worth holding on to in life and what you're allowed to let go," she added. "Being a little older, having gone through periods I don't want to go back to, means I appreciate life so much more now."
Outhwaite is married to fellow actor Tom Ellis. The couple have a 2-year-old daughter together named Florence.