Enduring changes in personality/attitudes , depression , spirituality , anxiety , wellbeing , substance misuse , meditative practice s , and mindfulness were documented .
Mystical experiences , connectedness , emotional breakthrough , and increased neural entropy were related to these long-term changes in psychological functioning .
Finally , with proper screening , preparation , supervision , and integration , limited aversive side effects were noted by study participants .
Research into the basic effects and therapeutic applications of  psychedelic drugs  has grown considerably in recent years .
Yet , pressing questions remain regarding the substances ' lasting effects .
Although individual studies have begun monitoring sustained changes , no study to- date has synthesized this information .
Dose-response study of N,N-dimethyltryptamine in humans. II. Subjective effects and preliminary results of a new rating scale.
BACKGROUND Validation of animal models of hallucinogenic drugs ' subjective effects requires human data . Previous human studies used varied groups of subjects and assessment methods . Rating scales for hallucinogen effects emphasized psychodynamic principles or the drugs ' dysphoric properties . We describe the subjective effects of grade d doses of N , N-dimethyltryptamine ( DMT ) , an endogenous hallucinogen and drug of abuse , in a group of experienced hallucinogen users . We also present preliminary data from a new rating scale for these effects . METHODS Twelve highly motivated volunteers received two doses ( 0.04 and 0.4 mg/kg ) of intravenous ( IV ) dimethyltryptamine fumarate " nonblind , " before entering a double-blind , saline placebo-controlled , r and omized study using four doses of IV DMT . Subjects were carefully interviewed after resolution of drug effects , providing thorough and systematic descriptions of DMT 's effects . They also were administered a new instrument , the Hallucinogen Rating Scale ( HRS ) . The HRS was drafted from interviews obtained from an independent sample of 19 experienced DMT users , and modified during early stages of the study . RESULTS Psychological effects of IV DMT  began almost immediately after administration , peaked at 90 to 120 seconds , and were almost completely resolved by 30 minutes . This time course paralleled DMT  blood levels previously described . Hallucinogenic effects were seen after 0.2 and 0.4 mg/kg of dimethyltryptamine fumarate , and included a rapidly moving , brightly colored visual display of images . Auditory effects were less common . " Loss of control , " associated with a brief , but overwhelming " rush , " led to a dissociated state , where euphoria alternated or coexisted with anxiety . These effects completely replaced subjects ' previously ongoing mental experience and were more vivid and compelling than dreams or waking awareness . Lower doses , 0.1 and 0.05 mg/kg , were primarily affective and somaesthetic , while 0.1 mg/kg elicited the least desirable effects . Clustering of HRS items , using either a clinical , mental status method or principal components factor analysis provided better resolution of dose effects than did the biological variables described previously . CONCLUSIONS These clinical and preliminary quantitative data provide bases for further psychopharmacologic characterization of DMT 's properties in humans . They also may be used to compare the effects of other agents affecting relevant brain receptors in volunteer and psychiatric population
Enduring changes in personality/attitudes , depression , spirituality , anxiety , wellbeing , substance misuse , meditative practice s , and mindfulness were documented .
Mystical experiences , connectedness , emotional breakthrough , and increased neural entropy were related to these long-term changes in psychological functioning .
Finally , with proper screening , preparation , supervision , and integration , limited aversive side effects were noted by study participants .
Research into the basic effects and therapeutic applications of  psychedelic drugs  has grown considerably in recent years .
Yet , pressing questions remain regarding the substances ' lasting effects .
Although individual studies have begun monitoring sustained changes , no study to- date has synthesized this information .