Wellbutrin can increase anxiety. I know for me it kept me from getting enough sleep. I am still taking it but have added Zoloft and I can sleep at night. Many people have said that Wellbutrin makes them more irritable and jittery. It could be the Wellbutrin giving him more anxiety. When my doctor first prescribed it for me he said it would increase my anxiety and he wanted to give me Prozac with it to counteract that effect. I refused the Prozac and just went on the Wellbutrin and he was right it made me too hyper and I actually cried more while only on that.