Old Great Dane separation anxiety

Question
We have a 10 yr old Great Dane displaying destructive behavior when being left alone. We have had her since she was 6 mo old.She relieves her bowels, even in her crate so we, let her have the run of the garage because she pulls carpet with her paws when in house This is still not good enough she  drools,tries to get in the house by clawing the door she also tries her best to escape. Sometimes she succeeds. She can open doors.  Deadbolts must be on. We let her out to have bm's before we leave, she waits to go in garage -after we leave.We took her to vet. She put her on Prozac. We are at our wits end. This behavior began about 6 mo ago. Could she have a mental disorder? Otherwise she is energetic and happy when we are in her presence. Help!

Answer
Cognitive dysfunction disorder.  Your dog is experiencing dementia and it seems that you are angry with her.  They do have target meds that can help doggie alzheimers. You need a qualified vet, and a realistic approach to handling a dog with a mind that is slipping. Locking her in the garage is not a great idea. She has given you 10 loyal years. She may have some added anxiety in her old age but please be patient with her. And I apologize for the lateness in the response, the website has been giving me problems with my login and vacation preferences.