Catatonic bearded dragon

Question
hey tracie, i have a 9 year old bearded dragon and i was wondering if he is suffering from a disease or just old age. recently, about a week ago, he began refusing food. He has become more and more apathetic to the point where he is almost catatonic, waking up every couple hours and moving only a couple inches. his eyes are usually closed, and when they are open they appear to be sunken inside his eye socket a little bit. the top of his head, where his head, where his eyes are, usually convex, is also sunken a little. also, he appears to be losing his motor control, i held a piece of lettuce in  front of his face and his targeting was all wrong. i hear i cracking sound too sometimes when i observe him im not sure what that is, maybe him grinding his teeth?
     im worried that i may have caused this affliction, because soon before he became ill i gave him crickets for the first time in a loooong time. he was primarily a herbivore for most of his adult life. i doubt it was caused by lighting or sand etc. because that has been the same all his life (the sand was cleaned of course).

Answer
Hello Chris,

Well, at age 9, he is certainly getting old but could live to be older though.
Let's see if there is anything that we can do for him.   
What type & brand of UVB lighting are you using, is it a flourescent tube bulb or a compact/coil light?  How OLD is the UVB light?
What type of basking light do you use, a bright white light or a colored light?
Do you supplement calcium?
Even being an adult, he does need protein his whole life.  He is probably suffering from malnutrition.  
He may even have metabolic bone disease from lack of proper UVB lighting as well as food intake.  They are omnivores which means they eat protein & vegetation.  
What are the temps in the tank?  What type of thermometer are you using, a stick on type, a digital probe or a temp gun?
I highly suggest getting some chicken or turkey babyfood with some squash babyfood & slowly begin to try & get a little food into him, daily along with some oral fluids.  
His fat pads being sunken in as well as his eyes too means he is very dehydrated & losing his fat intake.

Tracie