McIlroy, who slipped from the top of the rankings to world number six after a winless 2013, said the mental toll of sport could far outweigh the physical pressures and cases such as that of England cricketer Jonathan Trott were becoming more frequent.
Trott flew home from Australia on Monday to deal with a stress-related illness following England's calamitous start to the Ashes series.
"It's sad to see something like that happen and it just shows what a mental toll sport can take on you sometimes," McIlroy told reporters at Royal Sydney.
"Hopefully he gets home and spends some time with his family and recovers and can come back...
"As sport becomes so big and there's so much pressure and so much on the line, it's becoming more and more common that these sorts of stress-related illnesses are happening and it just shows how much of a mental toll it takes on you sometimes."
The 24-year-old acknowledged there was a world of difference between casual banter on the golf course and the sledging that took place in Brisbane, where England were thrashed by 381 runs in the first test.
"I think the sledging this year has probably been a bit worse than other years as well," the Northern Irishman added.
"It looks like they're just having a go at each other after every ball... it would be really tough to take that for however long you're out there for.
"They seem to really get at each other's throat whenever they're in there."
McIlroy has had to deal with a myriad of off-course distractions this year, but his form seems to be improving heading into the final events of the year.
In addition to his high-profile switch to Nike, a dispute with American sportswear company Oakley and his split with Dublin-based Horizon Sports Management, McIlroy has also had to deal with the media focus on his relationship with tennis star Caroline Wozniacki.
"It's been a long year, I guess mentally more than physically," he added.
"Physically, golf doesn't take that much out of you but mentally it's quite draining, especially this year for me, not just the golf and being frustrated with my game but having to answer the questions and having to come up with reasons why I'm not playing well and all that stuff."
McIlroy will face stiff competition at Royal Sydney from Masters champion Adam Scott and another Australian Jason Day, who won the World Cup's individual trophy by two strokes on Sunday.
"I've said for the last couple of months I just wanted to try and finish this season strongly and get some momentum to go in 2014," he added.
"This would be the perfect place to get that first win of the year and give me a sort of springboard into the next season."
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- Jonathan Trott