Background: Schizophrenia leads to multifunctional disability, characterized by cognitive and social impairments, everyday skill and self-assessment difficulties, and negative symptoms. Long-term clinical stability, often achieved with antipsychotics, improves everyday functioning. Aim: The goal is to determine to determine the efficacy of different antipsychotic classes (%Prob of APDs' Resp) and adherence rates, as measured by the Behavioural Adherence Rating Scale (BARS). Methods: The study focuses on schizophrenia-spectrum disorders in adults and elderly psychiatric patients, using established diagnostic systems. The observational and retrospective study will be conducted at the Princess Aisha Bint Al Hussein Medical Centre from January 2021 to January 2023. The study will use positive and negative symptom domains to measure initial severity and assess ideal values for antipsychotic drugs. A Chi Square test will be used to analyze distribution rates and odds ratios. The study will use SPSS version 25 with a 5% significance level. Results: The binary logistic regression model was created using patient adherence patterns evaluated using BARS. The model aimed to predict positive responsiveness (Δ PANSS≥20%) and negative responsiveness (Δ PANSS<20%) using patient data. The model accurately identified 94.4% of cases, with a chi-square value of 4.412 and a p-value of 0.818. BARS testing revealed a probable range of APDs' reaction from 64.4% to 88.2%, with individuals determining this range. The study suggests that the specific range may be different depending on the Cox & Snell R2 or Nagelkerke R2 procedures used, but all factors should be considered. The model's accuracy is significant, and the findings suggest that individuals are responsible for determining this range. Conclusion: The study reveals that psychotic individuals require 68.5% adherence for optimal responsiveness. Adding LAIAP to oral APDs enhances responsiveness.