Abuse Potential and Human Pharmacology of Methylone

Inclusion Criteria:

* Understanding and accepting all the study procedures and signing the informed consent.
* Healthy male and female volunteers aged between 18 and 45.
* Clinical history and physical examination demonstrating no organic or psychiatric disorders.
* The electrocardiogram and general blood and urine laboratory tests performed before the study must be within normal ranges. Minor or occasional changes from normal ranges are accepted if, in the investigator's opinion, considering the current state of the art, they are not clinically significant, are not life-threatening for the subjects and do not interfere with the product assessment. These changes and their non-relevance will be justified in writing specifically.
* Body weight between 50 and 90 kg and body mass index (BMI) between 19-27 kg/m². In case of women, they must weight at least 55 kg to participate. Lower or higher weights and/or BMIs will be accepted if the researchers consider that do not pose a risk to the subjects and do not interfere with the objectives of the study.
* Recreational use of methylone or other synthetic cathinones, amphetamines and/or ecstasy at least 6 occasions (two in the previous year) without serious adverse reactions.
* Women who have regular 26-32 day menstrual cycles (maximum 35 days). Participation only in follicular phase of menstrual cycle.
* Participants who agree to use reliable methods of contraception during the study such as abstinence, intrauterine devices, barrier methods with or without spermicide, or who have a vasectomized partner.

Exclusion Criteria:

* Present history of a substance use disorder according to Diagnostic and Statistical Manual for Mental Disorders (DSM-V), except for nicotine. Past history of mild substance use disorder (corresponding to substance abuse according to DSM-IV) could be included.
* Having had any somatic disease or having undergone major surgery in the 3 months prior to inclusion in the trial.
* Individual psychiatric history or schizophrenia in first-degree relatives.
* Previous or actual psychiatric disorders, alcoholism, abuse of prescription drugs or illegal substances or regular consumption of psychoactive drugs.
* Daily consumption of \>40 grams of alcohol and/or \>20 cigarettes.
* Blood donation 8 weeks before or participation in other clinical trials with drugs in the previous 12 weeks. In the exceptional case of having participated in this study, there is a washout period of 2 months.
* History of allergy or serious adverse reactions to medications and/or drugs.
* Pathological history or evidence of a preexisting condition (including gastrointestinal, liver, or kidney disorders) that may alter the absorption, distribution, metabolism or excretion of drugs or symptoms suggestive of drug-induced gastrointestinal irritation.
* Subjects unable to understand the nature, consequences of the study and the procedures requested to be followed.
* Subjects with positive serology to Hepatitis B, C or HIV.
* Having taken medication regularly in the month prior to the study sessions, excepting vitamins, herbal remedies or dietary supplements that, according to the researchers, do not pose a risk to the subjects and do not interfere in the objectives of the study. Single doses of symptomatic medication in the week prior to experimental sessions will be admitted if it is assumed that blood concentrations have been eliminated on the day of the experimental session.
* Women who are pregnant or breastfeeding, or who use hormonal contraceptives or do not use reliable contraceptive measures during the study (such as abstinence, intrauterine devices, barrier methods or with a vasectomized partner).
* Women with amenorrhea or severe premenstrual syndrome.