The Texan was set to join Jack Nicklaus, Nick Faldo and Tiger Woods as only the fourth player to win back-to-back green jackets at Augusta, when he blew a five-shot lead with nine holes to play.
The nadir of Spieth's spiral was a quadruple-bogey seven at the short 12th as he put two shots into the water guarding the green.
He rallied to finished tied second behind Danny Willett and has since won three PGA Tour titles and a dramatic British Open title at Royal Birkdale last July.
But Spieth's stellar rise after winning his first two major titles, the 2015 Masters and US Open, as a 21-year-old has leveled out, and he admits he let the Augusta agony "tear me down a little bit."
"It's been kind of a crazy over the last three or four years," he told reporters ahead of this week's Fort Worth Invitational at Colonial Country Club, Texas.
"Just had a lot of experiences that a lot of guys have over the course of 25 years within three years. Ups and downs and everything in between."
He added: "I've gotten pretty down on myself at certain moments. You know, say, after the '16 Masters as being like a low point in my golf career.
"That kind of haunted me and all the questioning and everything. I let it tear me down a little bit. I kind of lost a little bit of my own freedom, thoughts on who I am as a person and as a golfer."
Spieth remains winless in 2018 although he has had a number of top threes, including back at Augusta where he has finished outside the top three only once in five visits.
And though his trajectory of three majors before the age of 24 puts him second only to Nicklaus, Spieth says he is still adjusting to the trials and tribulations of a pro golfer's life.
"The majority of it very positive, but also learning to live in the spotlight and what that entails and what to block out, what to embrace," he said. "It's still a learning experience."
Spieth said there was a time when he "loathed" going to the golf course, but insists that despite his recent struggles he is now "loving what I do."
"I've just tried to really be selfish in the way that I think and focus on being as happy as I possibly can playing the game I love; not getting caught up in noise, good or bad," he added.
"[I'm] trying to stay pretty neutral and just look at the big picture things and try and wake up every single day loving what I do."
The next major, the US Open, is on the horizon at Shinnecock Hills, NY from June 14-17 when Spieth can overtake Nicklaus and sit second behind Woods as the youngest ever winner of four major titles.
He will defend his British Open title at Carnoustie in July and the following month he will have a second chance to clinch the career grand slam of all four major titles when he bids for the US PGA at Bellerive, Missouri.
Only five players have so far achieved the feat -- Gene Sarazen, Ben Hogan, Gary Player, Nicklaus and Woods. Phil Mickelson could also win a grand slam if he wins the US Open, while Rory McIlroy needs the Masters to complete the set.