Subjective symptoms of a panic attack will be assessed using the 28-item Acute Panic Inventory. The API will administered at the conclusion of the screening interview during which time they will be asked to describe a typical panic attack, prior to infusion of D5W, prior to lactate infusion, halfway through lactate infusion (10 min. into the infusion), and, if precipitated, at the emergence of a panic attack. To meet criteria for having a panic attack, a subject must experience a crescendo of anxiety, fear or apprehension, and at least 4 of the physical symptoms listed in DSM-IV-TR for a panic attack. Subjects who experience a panic attack will be offered lorazepam 0.5 mg po to alleviate panic attack symptoms.