Private health insurance

I have a three and half year old son who I am 99% sure has Aspergers. I haven't picked up the phone to the GP yet and so thus far there is nothing on his medical record. We have private health insurance through AXA and have not paid for the mental health option. Is Aspergers classed as a Neurological or Psychiatric issue? ie ought I add the mental health option before I talk to the GP?