AO3. Although flooding is cost effective, it can be highly traumatic for patients since it purposefully elicits a high level of anxiety. Wolpe recalled a case with a patient becoming so intensely anxious that she required hospitalisation. Although it is not unethical, as patients provide fully informed consent, many do not complete their treatment as it is too stressful. This means that flooding treatment can be a waste of time and money if patients do not complete their whole treatment.