Is there any difference between one-year MScs and two-years MScs? I am currently intending to apply for a master degree in Health/Clinical Psychology. I would like to ask if there is any difference in terms of qualification between an one-year MSc and a two-year one, that is, if they are recognised as of same value in any possible field of application. If not then what are the differences between them?
I am not sure about your field, and it also probably varies by university, but generally one year MScs are just course based, professional degrees that offer little to no funding (Meaning you pay out of pocket). Two year degrees, on the other hand, generally are thesis based degrees, are often funded (not as often as PhDs). Sometimes 2 year MScs are also course based, but I would look at credit requirements. Some schools offer programs where you can do the equivalent of a 2 year program in 1 year (non thesis based). 

In my field, Earth Sciences, a 1 year or 2 year non thesis based MSc is generally reserved for people who want to teach in High school (USA) or their company wants them to brush up on some new techniques in the field. Those who want to go on to a PhD program, or, get a high paying industry job (in oil/gas) tend to do thesis based degrees to be competitive. 

So more credits = better degree. Thesis = better degree. In general, of course.