Study to Compare Clozapine vs Treatment as Usual in People With Intellectual Disability & Treatment-resistant Psychosis

Randomized, open-label, multicenter phase II clinical trial that seeks to evaluate the safety and efficacy of clozapine versus standard clinical treatment in patients between the ages of 16 and 55 with intellectual disability and treatment-resistant psychosis. Clozapine is the most effective antipsychotic for patients with non-affective psychosis who do not respond to other first and second generation antipsychotic treatments. In addition, it has been shown to be very effective in another series of clinical situations such as hostility and aggressiveness, polydipsia and in behavioral disorders and psychosis, frequent situations in people with intellectual disabilities. The primary objective is to assess the efficacy and safety of clozapine versus standard clinical practice treatment in patients with intellectual disability and resistant psychotic disorder, as measured by change in Clinical Global Impression: Clinical Global Impression-Schizophrenia scale (ICG-SCH) global score over trial visits. The study determines to reach a sample size of 114 patients distributed among the 25 active centers. Randomization is 1:1 and consists of 6 visits to the center spread over 12 months. At each visit, the patient will undergo a physical examination and sample collection, along with a clinical and cognitive evaluation using the scales provided in accordance with the clinical guidelines. In addition, if the patient falls into the experimental arm (Clozapine), it is necessary to collect a blood sample weekly during the first 18 weeks and biweekly until completing the 12 months of the study, so that the medical team has special control in the analytical parameters.