Former England captain and TMS pundit
It can never be an easy decision to leave a World Cup, so Michael Yardy's clearly got himself into a state and been struggling for a while with his depression.
I was around the England team as captain when Marcus Trescothick started to suffer and left a tour of India, and I hope the likes of Marcus will potentially help Michael.
People have to understand that depression is not a sign of any kind of weakness, it just can happen. Michael has been away from home for a period of time, and whether it started before travelling this winter, only he will be able to say.
It's also a physical illness. I think as soon as you hear the word depression everyone just thinks it's purely mental. Of course there is a mental side to it, but it physically doesn't allow you to do what you want to do and in his case, that is to play cricket.
Vaughan and Trescothick helped England to win the Ashes in 2005
There's a lot of pressure playing in a World Cup - he probably would have felt he could have played a little bit better, but it's clear that if you've got these issues you're never going to get the best out of yourself.
It must have been a tough decision to make, but I'm sure that everyone around the ECB [England and Wales Cricket Board], the PCA [Professional Cricketers Association], all the players and his family back home will hopefully give him all the support he needs to help him come through this.
With Marcus, I think it was a surprise because no-one had really gone public with problems like this before, so it was a learning curve for everyone involved to understand how to deal with these issues.
Marcus wouldn't have been the first to suffer with this, and there will have been many, many more who haven't come out and who have fought through it and struggled for a long period.
The most important person involved in this is Michael Yardy. He's clearly going to need some help, but he loves playing cricket and he'll want to do that again as quickly as possible.
I really feel for him because at the time of Marcus' problems, if you had asked the other 15 players in the squad if they'd had noticed anything they would have said "no - he's just been normal".
I think the same could be said of this set of England players. They probably won't have seen too much wrong with Michael, and that just shows you how much acting these guys have to do in front of their team-mates, so it must be terrible when they're in their own room with no-one else watching them.
[Coach] Andy Flower and [captain] Andrew Strauss will be very concerned that one of the players in the England set-up is struggling and they'll want to get him as much support as possible.
There is now a bigger support group with the England team than there ever has been, but ultimately it comes down to the player. I can only imagine what Michael Yardy has been going through the last few days - he's clearly been struggling badly. I think he's done the right thing by telling the truth.
I bet there are players in other sports who are struggling with depression and maybe aren't being as upfront as some of the cricketers. I've said for a long time that the international cricket schedule is ridiculous, and maybe this will highlight the fact.
People will have their own opinions, but I just hope they're sympathetic towards a player who's desperate to play for England.
Shaun Tait and Damien Martyn had problems in the past with Australia, so it's obviously something that the ECB and the England management will have to study in the future - how they spot it, particularly in young players is difficult.
As far as the ICC technical committee is concerned, it's exactly the same as an injury and England should, without question, be allowed to replace Michael Yardy in this World Cup.
Michael Vaughan was talking on the BBC's Test Match Special programme.
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