The notion of genuine placebo effects on epileptic seizure events (i.e., effects beyond methodological study artifacts) is incompatible with the standard model of epilepsy seizure genesis. In this single-blind controlled study, the effectiveness of a covered placebo on (1) the timing of the occurrence of a first epileptic seizure ("seizure pill") versus (2) the subjective well-being ("comfort pill") during pre-surgical video-EEG monitoring will be examined. It is hypothesized that a placebo effect on subjective well-being can be demonstrated, but that epileptic seizure events are not influenced by placebo.

Patients undergoing long-term video-EEG monitoring for the purpose of pre-operative epilepsy diagnostics will be invited to participate in the study. Patients will be pseudo-randomized into three study conditions (in blocks of six). The study participants will take a placebo pill designated either as a "seizure pill" (Condition PCB-S) or a "comfort pill" (PCB-W) in addition to their regular medication in the morning and evening, or not receive any additional placebo medication (No-PCB).

Both the "seizure pill" and the "comfort pill" are commercially available, ingredient-free placebo pills (P-pills blue Lichtenstein, produced by Winthrop Pharmaceuticals). No further details about the composition of the pill will be provided; information about the ingredients of the respective pill will be provided after the end of the entire study. Depending on randomization, study participants will be informed that this pill is expected to (1) either facilitate/accelerate the occurrence of epileptic seizures (PCB-S) (thereby shortening the required time for video-EEG monitoring), or (2) to lead to a more stable/improved emotional well-being during the stay in the V-EEG (PCB-W) or (3) will not receive a pill but are asked to fill-in questionnaires and diaries like the other patients.Start of the V-EEG will be documented as the starting point for latency measurement for the occurrence of a first epileptic seizure. The patients will be pseudo-randomized into the three study conditions: Out of every 6 patients, 2 will be assigned to each of the three study conditions. Patients in both active study conditions will receive the first pill at the start of the V-EEG. After that, study participants will receive the respective "pill" morning and evening in addition to their other medications, however, visibly separated from them and clearly marked as study medication. All participants, including controls, will keep a seizure diary during the V-EEG. In addition, they will fill-in a newly constructed ad-hoc questionnaire at the beginning and after the V-EEG. Finally, all patients will be asked twice daily (around 9 AM and around 6 PM) about their overall emotional well-being using a visual analogue scale (VAS; 0 very bad ... 100 extremely good). The highly standardized clinical procedures of presurgical evaluation are in no way affected by the study. In particular, anti-seizure medications for all patients will be tapered off following exactly the same schedule without any influence from the study; the medication will be precisely documented.

Inclusion Criteria:

• eligibility for presurgical epilepsy diagnostics

Exclusion Criteria:

• inclusion criterion implies all exclusion criteria for this procedure
• legal guardian
• lack of consent or lack of capability to provide informed consent

Like in psychological studies, only patients can participate in the study who consent to accept that complete study information can only be provided after the entire study was finished (with an option to withdraw consent at that point) as information on ingredients of the study pill (which is placebo) must be concealed for inherent reasons (study on effects of covered placebo).