Brief Answer:
Try antidepressant like amitriptyline
Detailed Answer:
HI
Thanks for using healthcare magic. I, Dr Abhishek Kapoor, would help you in this query.
Dizziness is common in elderly people. 30% of people older than 65 years experience dizziness in some form and it increase up to 50% in the very old (older than 85 years). 
Cardiovascular disease is considered to be the most common major contributory cause of dizziness (57%), followed by peripheral 
vestibular disease (14%), and psychiatric illness (10%). An adverse drug effect is considered to be the most common minor contributory cause of dizziness (23%). 
In your case, you have dizziness for last 14 years. Your 
thyroid profile and cardiovascular function is normal, in that case, try to rule out any underline problem in peripheral 
vestibular system i.e. ear or eye. If you have already got it properly investigated, then chances of psychological dizziness is more.
In that case, i would suggest you to try some antidepressant like amitriptyline or 
imipramine at low dose with 
lorazepam. These drugs have anti-histaminic effect and it would help to control anxiety with dizziness. With these drugs, you can also decrease dose of lorazepam. Better to discuss all this with your physician.
In case, you need further help, you can ask.
Regards
Dr. Abhishek Kapoor
Psychiatrist