Can nitrous oxide cause severe anxiety and panic attacks?

Possibly: First, it is a sympathy mimetic agent, so it may directly cause that reaction, although I have never seen it. Also, simply the process of initiating the anesthetic, breathing through the mask, may trigger an attack. Ask your doctor to prescribe an anxiolytic to those before your next procedure.

Not directly: In some individuals who are clostraphobic, wearing a nasal mask can produce these unpleasant symptoms. Usually is notice within a few minutes that this is the case. Anxiety and panic symptoms are not from the direct effects of nitrous oxide.