Shar,it isnt like having physical symptoms,you DO have physical symptoms. Sweating,shaking,palpitations,terrible muscle spasms and pain,headaches and even altered mental status.
Any pain or sedative/anti anxiety medication withdrawl after longterm use will cause all of the above.Some people choose to go cold turkey and will feel very ill for a short time and can as Gary said risk serious consequences,but the sensible thing to do is get a graduated withdrawl programme set out.

love liz