Does 2nd season syndrome actually exist?

Swansea, Norwich City and QPR all did themselves proud in the 2011/2012 Premier League season by managing to avoid relegation after gaining promotion in the previous campaign, but will any of them catch a case of 2nd season syndrome?

Second season syndrome is the now-common phrase that is used to describe a downturn in fortunes for a football club two seasons after its promotion to the Premier League of English football – particularly if the first season after promotion had brought a strong finish.

Here are a few examples over the years of 2nd season syndrome and the teams that have been affected by it:

2006–07 season