Molecular Imaging Study of Harmine/DMT: a Basic Research Approach

Inclusion Criteria: * Between 25-45 years old * Good command of the German language * Willing and capable to give consent for the participation in the study after it has been thoroughly explained * Willing and capable to comply with all study requirements * Body mass index (BMI) between 18.5 and 35 * Previous experience with psychedelics, but not in the past three months * Willing to abstain from alcohol, caffeinated drinks, nicotine, food, and sugary drinks for two hours prior to the PET scan on the testing day, and from consuming psychoactive substances for 2 weeks before the first testing day and for the duration of the study Exclusion Criteria: * Previous significant adverse response to a psychedelic drug * Recent or concurrent participation in another study where pharmaceutical compounds will be given * Presence of Axis I affective, anxiety, or dissociative disorders * Present or antecedent diagnosis of bipolar disorder (I, II, not otherwise specified), schizophrenia, schizoaffective disorder, psychosis, or other disorders from the psychotic spectrum * First-degree relatives with present or antecedent schizophrenia, schizoaffective disorder, or bipolar disorder type I * History of head trauma, seizures, cancer, or cerebrovascular accidents * Recent cardiac or brain surgery * Current abuse of medication or psychotropic substances according to SCID I criteria * Presence of major internal or neurological disorders (including sepsis, pheochromocytoma, thyrotoxicosis, drug-induced fibrosis, familiar or basilar artery migraine) * Cardiovascular disease (hypertonia, coronary artery disease, heart insufficiency, myocardial infarction, coronary spastic angina) Version 5, 15/11/2023 16/44 * Peripheral vascular disease (thromboangiitis obliterans, luetic arteritis, severe arteriosclerosis, thrombophlebitis, Raynaud's disease) * Cerebrovascular disease (e.g., stroke, intracranial bleeding / hemorrhage, intracranial aneurysm) * Diabetes Type 1/2, Metabolic Syndrome * Serious abnormalities in ECG or blood count/chemistry * Liver or renal or pulmonary disease * Inability to lie still in the scanner for about 90 minutes (e.g., because of sneezing, itching, tremor, pain) * Left-handedness * Significant radiation exposure (either X-ray or nuclear medicine studies) in the last 12 months * Presence of claustrophobia or other contraindications to PET scanning * Presence of contraindications to MRI investigations: Magnetic parts in the body (piercings, brain aneurysm clip, implanted neural stimulator/cardiac pacemaker/defibrillator/Swan Ganz catheter/insulin pump, cochlear implant); metal shrapnel or bullet, ocular foreign body (e.g., metal shavings); current or previous job in metalworking industry * Current use of medications with significant interaction potential with MAO inhibitors (e.g., antidepressants, antipsychotics, psychostimulants, dopaminergic/serotonergic agents, anticonvulsants) * High risk of adverse emotional or behavioral reaction based on investigator's clinical evaluation (e.g., evidence of serious personality disorder, serious current stressors, lack of social support).