It was suspected that the delusional convictions of bewitchment and devil persecution of two female patients (41 and 40-years-old) could be the consequence of an erroneous interpretation of the sensations induced by panic attacks, as several authors have previously suggested. The interest of this case report stems from the manner in which we tested our clinical hypothesis. The patients agreed to the use of a lactate provocation test in double-blind, placebo-controlled conditions during four randomized sessions on consecutive days (two with lactate and two with placebo). The results for patient A strongly supported our hypothesis: patient A developed two full-blown panic attacks during the active lactate sessions, whereas patient B developed one subthreshold and one moderate panic attack during the active lactate sessions. The results of these investigations led to a more specific psychotherapeutic approach for patient A.