Prescription drug use was classified as psychotropic or non-psychotropic medication use. Psychotropic medications, identified using the American Hospital Formulary Service Classifications, included lithium, anticonvulsants, antipsychotics, antidepressants, stimulants, anxiolytics/sedatives/hypnotics, and other psychotropic agents (including anti-parkinsonian agents, and two alpha-agonists prescribed for attention deficit hyperactivity disorder - clonidine and guanfacine). All other drugs were categorized as non-psychotropic medications.
