Reply to Letter to the Editor "Need for a New Framework to Understand the Mechanism of All Antipsychotics"

Letter to the Editor

Sir: We appreciate the comments by Stip and colleagues andwould like to respond to several issues they have raised.

They suggest that the notion of D₂ occupancy thresholds forclinical response and extrapyramidal symptoms (EPS) (approximately60% and 80%, respectively) does not adequatelyaccount for that group of individuals who require higher antipsychoticdoses than what this model might predict. This is true.Certain individuals, albeit a small subgroup, appear to benefitfrom high-dose therapy, reminding us that existing theories arenot absolute.