MDMA in Subjects With Moderate Hepatic Impairment and Subjects With Normal Hepatic Function

Inclusion Criteria: * Participants with moderate hepatic impairment (class B according to Child- Pugh's criteria). * Participants with normal hepatic function: no clinically significant findings from medical history, physical examination, laboratory values within protocol defined parameters. * Age 18 to 65 years. * Weight \> 45 kg * Negative Carbohydrate Deficient Transferrin blood test at Screening and negative breathalyzer alcohol test prior to trial drug administration. * Negative urine test for drugs of abuse at Screening and prior to trial drug administration. * Able to comprehend and willing to sign an informed consent form. Exclusion Criteria: * Have a current psychiatric diagnosis. * Are pregnant or nursing, or are women of child bearing potential who are not practicing an effective means of birth control. * Have acute or exacerbating hepatitis, fluctuating or rapidly deteriorating hepatic function as indicated by widely varying or worsening of clinical and/or laboratory signs of hepatic impairment within 2 weeks. * Have autoimmune liver disease; esophageal variceal bleeding within 6 months prior to screening, unless successfully treated with banding, or gastric varices. * Have spontaneous bacterial peritonitis within 3 months prior to screening. * Have a portosystemic shunt, organ transplant, Wilson's disease, cholestatic liver disease (e g, primary biliary cirrhosis or primary sclerosing cholangitis) * Evidence or history of significant hematological, endocrine, cerebrovascular, cardiovascular (including controlled hyper-tension), coronary, pulmonary, renal, gastrointestinal, immunocompromising, or neurological disease, including seizure disorder, or any other medical disorder judged by the investigator to significantly increase the risk of MDMA administration. * For moderate hepatic impairment participants: have clinically significant laboratory findings except as related to hepatic impairment. * For control participants only: have clinically significant laboratory results outside the normal limits, including AST \>48 U/L, ALT \> 55 U/L, GGT \> 48 U/L, bilirubin \> 1.2 mg/dL or hemoglobin \< 12 g/dL. * Have a history of any illness that, in the opinion of the Investigator, might confound the results of the trial or pose risk in administering the trial drug to the subject. * Have any positive test for drugs of abuse and /or alcohol at screening. * Have a history or presence of clinically significant abnormal 12-lead ECG or an ECG with QTc by Bazett's correction of \> 450 ms in men, \> 470 ms in women on the screening ECG. * Have a PR interval \> 240 ms, QRS \> 110 ms or a history of prolongation of QT interval. * Have mental incapacity, unwillingness or language barriers precluding adequate understanding or subject co-operation. * Are unwilling to stay in the clinical unit for the required duration as per the protocol. * Have a known or suspected allergy to trial product or related products.