- Exposure to any psychoactive or otherwise excluded medication within five half-lives of the baseline visit or during the study. Excluded medications include: antidepressants, anxiolytics, anticonvulsants, barbiturates, chloral hydrate, lithium, antipsychotics, benzodiazepines, hypnotics, monoamine oxidase inhibitors (MAOIs), muscle relaxers, triptans, centrally-acting antihistamines, central alpha-2 agonists, decongestants, psychostimulants, dopamine agonists, opioid pain medications, oral corticosteroids, L-methylfolate, S-adenosyl methionine (SAMe), 5-HTP (hydroxytryptophan), St. John's Wort,