Presumed disabilities are a chronic long-lasting  illness that first appears within one year after discharge or caused by contact with contaminants or other hazardous materials or an illness caused by time as a POW.
another question for you regarding How will I get these benefits? What Should I Do When I File A Disability Claim?
When you file a claim you must complete one of these additional forms:- A statement in support of the service connection claim for post-traumatic stress disorder VA Form 21 - 0781.-Download VA Form 21 - 0781 PDF or
Can I get VA disability benefits?