To strengthen the nervous system, I would recommend sage, rosemary, and juniper berries. The amino acid L-glutamine can also help. It is the only thing other than glucose that the brain can use for fuel. Amino acids must be taken at least 20 minutes before meals so that absorption will not be interfered with. I would also recommend a good herb based vitamin supplement.
Natural vitamins work better than synthetic ones.
The supplement should contain kelp which is a good source of B vitamins and trace minerals, pulls heavy metals from the body, and supports adrenal function.