Objective The aim of this study was to evaluate the relationship between antipsychotic-induced tardive dyskinesia (TD) and estimated dopamine D2 receptor occupancy levels in patients with schizophrenia using the dataset from your Medical Antipsychotic Trials in Treatment SF1670 Effectiveness (CATIE). those with a score of zero using the Mann-Whitney U test. Results Estimated dopamine D2 receptor occupancy levels at trough were significantly higher in subjects who developed involuntary motions (N=23) than those who did not (N=195) (71.7±14.4% vs. 64.3±19.3% p<0.05) while no significant SF1670 difference was found in the estimated maximum D2 receptor occupancy between them (75.4±8.7% vs. 72.1±9.9% p=0.07). When SF1670 the analyses were SF1670 separately carried out for the three medicines there were no significant variations in estimated maximum or trough D2 occupancy although the values were consistently numerically higher among those developing involuntary motions. Summary Greater dopamine D2 receptor blockade with antipsychotics at trough might increase the risk of tardive involuntary motions although this getting needs to become replicated in larger tests. x [plasma level / (plasma level + ED50)] where is the maximum receptor occupancy attributable to the antipsychotic drug and ED50 is the estimated plasma concentration of the antipsychotic drug associated with 50% receptor occupancy which was obtained in the systematic review and pooled analysis (Risperidone active moiety: a=88.0% ED50=4.9 ng/ml; olanzapine: a=90.7% ED50=7.1 ng/ml; ziprasidone: a=88.2% ED50=32.9 ng/ml) (Uchida et al. 2011 This estimation method was previously developed for haloperidol by Fitzgerald et al. (Fitzgerald et al. 2000 2.4 Statistical analysis Statistical analyses were performed by using the SPSS Version 21.0 (IBM New York). Subjects were divided into two organizations based on the presence of TD. The estimated maximum and trough dopamine D2 receptor occupancy levels were compared between individuals who presented with an Seeks score of ≥2 at endpoint and those whose Seeks score remained at zero using the Mann-Whitney U test respectively. Likewise oral doses were compared between those two organizations in the total sample and subgroups of individuals receiving those three medicines respectively using the Mann-Whitney U test. For this analysis oral doses (mg/day time) were converted to Defined Daily Dose (DDD) Unit. This unit of measurement used for standardizing antipsychotic doses was developed from the World Health Corporation Collaborating Centre for Drug Statistics Methodology system of Defined Daily Doses (WHO. Collaborating Centre for Drug Statistics Strategy 2013 The DDD unit is the assumed average dose (mg) per day for a drug used for its main indicator in adults (e.g. SF1670 schizophrenia for antipsychotics): 5 for risperidone (oral) 10 for olanzapine (oral) and 80 for ziprasidone. In addition a binary PECAM1 logistic regression model was used to examine the effects of estimated dopamine D2 receptor occupancy levels age group (i.e. <50 or ≥50 years) sex antipsychotics years since the 1st antipsychotic was prescribed the duration of study participation and race (i.e. Caucasian African-American Native American or others) on the presence of TD. A p-value of <0.05 was considered statistically significant (two-tailed). 3 Results 3.1 Subject characteristics Two hundred and eighteen subject matter were included; demographic and medical characteristics are summarized in Table 1. Mean±SD daily doses of risperidone olanzapine and ziprasidone on the day of Seeks score assessments at endpoint were 4.6±1.3 mg 21.6 mg and 123.0±34.3 mg respectively. Mean±SD Seeks SF1670 score at endpoint was 0.39±1.26. Table 1 Demographic and Clinical Characteristics of the Subjects (N = 218). 3.2 Association between estimated D2 receptor occupancy and TD Estimated dopamine D2 receptor occupancy levels at trough were significantly higher in subject matter who presented with an AIMS score of ≥2 at endpoint (N=23) versus those with a score of zero (N=195) (71.7±14.4% vs. 64.3±19.3% p<0.05) while no significant difference was found in the estimated maximum D2 receptor occupancy between them (75.4±8.7% vs. 72.1±9.9% p=0.07). When the same analyses were separately conducted for those three individual antipsychotics there were no significant variations in estimated maximum and trough D2 receptor occupancy for any of them between subjects who presented with an Seeks score of ≥2 at endpoint versus those with a score of zero (risperidone 77.7 (N=8) vs. 74.6±6.3% (N=70) at maximum and 76.0±4.5% vs. 71.0±8.6% at trough; olanzapine 77.8 (N=12) vs. 75.0±8.0% (N=88) at maximum and 75.3±9.1% vs. 71.9±10.1% at trough; ziprasidone 59.6 (N=3) vs..