Effect of Ketanserin After LSD Administration

Visual Analog Scales (VAS) will be repeatedly used to assess subjective alterations in consciousness over time. VAS will be presented as 100 mm long horizontal lines marked with "not at all" on the left and "extremely" on the right. The following VAS will be used: "any effect", "good effect", "bad effect", "fear", "stimulated", "nausea", "tiredness", "alteration of hearing", "alteration of vision", "synesthesia", "alteration in sense of time", "the boundaries between myself and my surroundings seemed to blur", "talkative", "open", "trust" and "my focus is directed: outward/inward". Subjects will mark the scale with vertical lines.

Visual Analog Scales (VAS) will be repeatedly used to assess subjective alterations in consciousness over time. VAS will be presented as 100 mm long horizontal lines marked with "not at all" on the left and "extremely" on the right. The following VAS will be used: "any effect", "good effect", "bad effect", "fear", "stimulated", "nausea", "tiredness", "alteration of hearing", "alteration of vision", "synesthesia", "alteration in sense of time", "the boundaries between myself and my surroundings seemed to blur", "talkative", "open", "trust" and "my focus is directed: outward/inward". Subjects will mark the scale with vertical lines.

LSD plasma concentrations will be measured repeatedly over time using LC-MS/MS techniques (nanogram per milliliter scale).

LSD plasma concentrations will be measured repeatedly over time using Liquid chromatography-mass spectrometry (LC-MS)/MS techniques (nanogram per milliliter scale).

Visual analog scale consisting of 94 items. Constructed of five scales and allows assessing mood, anxiety, derealization, depersonalization, changes in perception, auditory alterations, and reduced vigilance. Scales will be presented as 100 mm long horizontal lines marked with vertical lines by the participant.

The adjective mood rating scale (AMRS or EWL60S) is a 60-item 4-point Likert scale ("not at all", "somewhat", "rather", "strongly") that allows repeated assessment of mood in 6 dimensions: activation, inactivation, well-being, anxiety/depressed mood, extroversion and introversion, and emotional excitability.The AMRS consists of subscales measuring "activation", "positive mood", "extroversion", "introversion", "inactivation", and "emotional excitability".

This 100-item questionnaire is rated on a 6-point scale (0=none, not at all; 1=so slight cannot decide; 2=slight; 3=moderate; 4=strong (equivalent in degree to any previous strong experience or expectation of this description); 5=extreme (more than ever before in my life and stronger than 4)). Forty-three items embedded into this questionnaire comprise the Mystical Experience Questionnaire (MEQ). The 43 items provide scale scores for each of seven domains of mystical experiences: internal unity (pure awareness, a merging with ultimate reality), external unity (unity of all things, all things are alive, all is one), sense of sacredness (reverence, sacred), noetic quality (encounter with ultimate reality, more real than everyday reality), transcendence of time and space, deeply felt positive mood (joy, peace, love), paradoxicality/ineffability (claim of difficulty in describing the experience in words).

Repeatedly measured using blood pressure / pulse apparatus (mmHg scale).

Repeatedly measured using blood pressure / pulse apparatus (beats per minute scale).

Repeatedly measured using ear thermometer (degree Celsius scale).

Repeatedly measured using pupil distance meter (millimeter scale).

Assesses the personality trait humility through 13 items on a 5-point Likert scale ranging from "strongly disagree" to "strongly agree".

Assesses the personality trait humility through 18 items on a 5-point Likert scale ranging from "not at all" to "strongly".

Assesses the personality trait of sensation seeking, which is is defined as a need for novel and intense stimulation. It uses 20 items using 4-point scales (1 = "describes me very well" to 4 = "does not describe me at all").

The FPI-R version comprises 138 items and covers 12 dimensions of personality: life satisfaction, social orientation, performance orientation, inhibition, excitability, aggressiveness, stress, physical complaints, health concerns, openness, as well as the secondary factors according to Eysenck's Extraversion and Emotionality (Neuroticism). It uses a 2-point scale ("true" and "not true").

The SPF defines empathy as the "reactions of one individual to the observed experiences of another." It assesses 28-items on a 5-point Likert scale ranging from "Does not describe me well" to "Describes me very well". The measure has 4 subscales (Perspective Taking, Fantasy, Empathic Concern, Personal Distress) each made up of 7 different items.

The DSQ-40 can provide scores for 20 individual defenses, and scores for the three factors "mature", "neurotic", and "immature". Each item is evaluated on a scale from 1 to 9, where "1" indicates "completely disagree" and "9" indicates "fully agree".