Donepezil for mild thinking difficulties

Age between 50 and 80 years (inclusive). Diagnosis of Parkinson's disease based on MDS criteria Neuroimaging compatible with Parkinson's disease Hoehn and Yahr stage (H&Y) I-III (inclusive). Persistent subjective cognitive complaints in the 6 months prior to screening. Diagnosis of Parkinson's disease-related mild cognitive impairment (PD-MCI) according to MDS PD-MCI criteria: Level I: MoCA ≤24 and ≥20(46) and Level II: 2/10 neuropsychological tests altered with a cutoff of 1.5 Standard Deviations(47,48). Duration of PD-MCI for at least 3 months prior to screening. Stable dopaminergic treatment in the 4 weeks prior to screening. Criteria for dementia associated with Parkinson's disease Insufficient proficiency in Spanish or the local language, illiteracy, sensory impairments (vision, hearing), legal incapacity, or any other mental, physical, or social condition that impedes giving informed consent or completing assessments adequately. History of symptomatic orthostatic hypotension. Pregnancy, desire for conception, refusal to use appropriate contraceptives during the study period and up to 6 months after, or lactation (see section 9.6). Any significant abnormalities in medical history, examination, vital signs, laboratory tests, or ECG that, at the investigator's discretion, contraindicate participation in the study. Severe motor complications (moderate to severe motor fluctuations defined as a score >1 on item 42 of Part IV of the MDS UPDRS; or disabling dyskinesias defined as a score >1 on item 36 of Part IV of the MDS UPDRS). History of Deep Brain Stimulation. Active psychosis or treatment with antipsychotic medications, major hallucinations, HADS score ≥11, active impulse control disorder, or other severe active behavioral disorders. Active treatment with anticholinergics, acetylcholinesterase inhibitors, or other systemic cholinergic enhancers, neuroleptics, potent CYP3A4 or 2D6 inhibitors, enzyme inducers, or drugs prolonging the QTc interval (see section 6.7). Hypersensitivity or intolerance to donepezil, piperidine derivatives, lactose, or any of the excipients of the active drug. History or impression, at the investigator's discretion, of poor therapeutic compliance. Unstable medical or surgical condition, or life expectancy of <1 year. Brain condition that may contribute to cognitive decline (history of stroke, brain tumor, neurosurgical intervention, etc.), including the presence of grade III leukoaraiosis on brain neuroimaging.