GH Research PLC, a clinical-stage biopharmaceutical company, engages in developing various therapies to treat psychiatric and neurological disorders. The company develops 5-Methoxy-N,N-Dimethyltryptamine (5-MeO-DMT) therapies for the treatment of patients with treatment-resistant depression (TRD). Its lead program is GH001, an inhalable mebufotenin product candidate that has completed two Phase 1 clinical trials and Phase 1/2 clinical trial in patients with TRD. The company also develops GH002, an intravenous mebufotenin product candidate; and GH003, an intranasal mebufotenin product candidate, which are in preclinical development trials with a focus on psychiatric and neurological disorders. GH Research PLC was incorporated in 2018 and is based in Dublin, Ireland.

COMPASS Pathways plc operates as a mental health care company primarily in the United Kingdom and the United States. It develops COMP360, a psilocybin therapy that is in Phase III clinical trials for the treatment of treatment-resistant depression; and is in Phase II clinical trials for the treatment of post-traumatic stress disorder and anorexia nervosa. The company was formerly known as COMPASS Rx Limited and changed its name to COMPASS Pathways plc in August 2020. COMPASS Pathways plc was incorporated in 2020 and is headquartered in London, the United Kingdom.

ATAI Life Sciences N.V., a clinical-stage biopharmaceutical company, engages in acquiring, incubating, and developing various therapeutics to treat depression, anxiety, addiction, and other mental health disorders. Its principal clinical programs include RL-007, a pro-cognitive neuromodulator for cognitive impairment associated with schizophrenia; GRX-917, a deuterated etifoxine for anxiety disorders; VLS-01 a N,N-Dimethyltryptamine for treatment resistant depression (TRD); DMX-1002, an oral formulation of ibogaine, a cholinergic, glutamatergic and monoaminergic receptor modulator that is a naturally occurring psychedelic product isolated from a West African shrub for the treatment of opioid use disorders (OUD); and EMP-01, an oral formulation of an MDMA derivative being developed for the treatment of post-traumatic stress disorder. The company's other clinical programs comprise PCN-101, a subcutaneous formulation of R-ketamine, as a therapy for psychiatric indications initially focused on TRD; and KUR-101, a formulation of deuterated mitragynine for the treatment of OUD. ATAI Life Sciences N.V. was founded in 2018 and is headquartered in Berlin, Germany with offices in New York and London.