The equality act does not address specific disabilities. It just prohibits discrimination on the basis of disability. For ptsd to be included it must be severe enough to be a disability.
The person must have an impairment that is either physical or mental The impairment must have adverse effects which are substantial The substantial adverse effects must be long-term The long-term substantial adverse effects must be effects on normal day-to-day activities
The above defines disability
Generally it must be present for 12 months. So if the ptsd can be classified as a disability, then the equality act would apply
Hope this helps