PSYB2 exam changes 2012 ?

I am revising for my resit of PSYB2 and looked at the specification and it said :

Explanations of phobias including behavioural and psychodynamic.
Explanations of OCD including biological and cognitive.

Does that mean we don't need to know the other explanations each ?

thanks for your help

It means that the exam board can only ask you about these explanations directly. For example:

"Describe and discuss the psychodynamic explanation of phobias. Refer to empirical evidence in your answer. (10 marks)"

They cannot ask you explicitly about any other approach if it isn't listed. However, knowing others can help you criticise an approach in a long answer question.