My husband has been on Atenolol for years. Depression, irritability and anxiety as well as not wishing to engage in normal daily activities are listed side effects of this medication.
I would imagine changes in attitude or mood would occur when weaning off of the drug. If it gets really bad, call your doctor office and see what they recommend, but it is probably normal.
Hubby gets irritable and sometimes lethargic. The Atenolol might be the reason why but he is on several other medications as well.
Best of luck and let us know how it goes!
Lindaru