Acute Effects of 3,4-methylenedioxymethamphetamine (MDMA) With and Without a Booster Dose

Assessed by visual analog scale (VAS) using 10% of the individual maximal subjective response (Emax) as threshold for the onset and offset.

Maximal subjective response (Emax), of "any drug effect" assessed by visual analog scale (VAS).

Area under the effect curve (AUEC) of "any drug effect" assessed by visual analog scale (VAS).

Effect duration for "good drug effect", "bad drug effect", "liking", "stimulated", "high", "anxiety", "I am emotional", "talkative", "happy", "open", "trust", "feeling close to others", "want to be alone", and "want to be with others", assessed by visual analog scale (VAS) using 10% of the individual maximal subjective response (Emax) as threshold for the onset and offset.

Maximal subjective response (Emax) of "good drug effect", "bad drug effect", "liking", "stimulated", "high", "anxiety", "I am emotional", "talkative", "happy", "open", "trust", "feeling close to others", "want to be alone", and "want to be with others", assessed by visual analog scale (VAS).

Area under the effect curve (AUEC) of "good drug effect", "bad drug effect", "liking", "stimulated", "high", "anxiety", "I am emotional", "talkative", "happy", "open", "trust", "feeling close to others", "want to be alone", and "want to be with others", assessed by visual analog scale (VAS).

The Adjective Mood Rating Scale (AMRS) assesses the occurrence and intensity of 60 moods on a 4-point Likert scale ranging from "not at all" to "extremely".

Blood pressure (systolic and diastolic) will be measured with an automatic oscillometric device.

Heart rate will be measured with an automatic oscillometric device.

Body temperature will be measured with an ear thermometer.

The 2011 revised Beschwerden-Liste (B-LR) consists of a 40-item list covering a wide variety of symptoms and complaints that are answered with a four-point intensity-scoring ranging from "not at all" to "strong".

The Warwick-Edinburgh Mental Well-Being Scale (WEMWBS) is a 14-item questionnaire, that covers different concepts associated with positive mental health, including both hedonic and eudaimonic aspects, positive affect, satisfying interpersonal relationships and positive functioning. For each item an ordinal five-point frequency answer format, ranging from 1 = none of the time" to 5 = "all of the time" is applied.

The General Health Questionnaire (GHQ-12) consists of a 12-item questionnaire with a four-point response scale assessing general psychological discomfort.

The Scale of Positive and Negative Experience (SPANE) is a 12-item questionnaire to capture the affective component of subjective well-being. The SPANE includes six items to assess positive feelings and six items to assess negative feelings. The feelings are reported on a 5-point scale ranging from "very rarely" to "very often or always".

The Insomnia Severity Index (ISI) is a self-report instrument to assess subjective sleep complaints, screen for insomnia and evaluate treatment response. It consists of seven items scored on a five-point Likert-scale.

Assessed via blood samples. Findings will be described descriptively including maximal concentration (Cmax), time to Cmax, (Tmax) area under the concentration-time curve up to 9 h (AUC0-9) and elimination half-life values.

Assessed via blood samples. Findings will be described descriptively including maximal concentration (Cmax), time to Cmax, (Tmax) area under the concentration-time curve up to 9 h (AUC0-9) and elimination half-life values.

Assessed via blood samples.

The "Positive Attitude towards Life" is an 8-item subscale of the 39-item Bern Subjective Well-Being Questionnaire for Adolescents (BFW/E). The BFW enables a reliable and valid assessment of different dimensions of subjective well-being in adolescents and adults. Changes over the course of the study are assessed.

Global life satisfaction is assessed based on a single item life satisfaction measure. The question can be answered on a 11-point scale: "In general, how satisfied are you with your life if 0 means 'not at all satisfied' and 10 means 'completely satisfied'?". Changes over the course of the study are assessed.

Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The NEO Five Factor Inventory (NEO-FFI) is a self-description questionnaire with 60 items for the measurement of the "big five": neuroticism, extraversion, openness, agreeableness, and consciousness. It uses a 5-point Likert scale ranging from "completely disagree" to "fully agree".

Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The Freiburger Personality Inventory (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").

Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The Saarbrücker Persönlichkeitsfragebogen (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.

Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The HEXACO personality inventory is a six-dimensional model of human personality with 100 items.The six factors are: Honesty-Humility, Emotionality, Extraversion, Agreeableness, Conscientiousness and Openness to Experience.

Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The Defense Style Questionnaire (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".