Inclusion Criteria:
* Provide written informed consent voluntarily after full comprehension of the study.
* Be aged ≥18 years, male or female.
* Meet the diagnostic criteria for Parkinson's disease according to the Chinese Diagnostic Criteria for Parkinson's Disease (2016 Edition), with a modified Hoehn-Yahr stage ≤3.
* Have insomnia symptoms \[reduced total sleep time (\<6.5 h) and/or sleep-onset latency \>30 min, and/or ≥2 nocturnal awakenings, early-morning awakening, or poor sleep quality\], occurring at least three times per week, accompanied by daytime dysfunction or daytime distress, with adequate opportunity for sleep yet difficulty initiating or maintaining sleep, and that cannot be fully explained by another sleep-wake disorder; and have satisfactory control of Parkinson's disease motor symptoms \[MDS-UPDRS Part III (ON state) score ≤30\].
* Be on a stable anti-Parkinsonian medication regimen, defined as no change in the type, dosage, or frequency of anti-Parkinsonian drugs for at least 4 weeks prior to enrollment, with no motor fluctuations or dyskinesia.
* Have a clinical decision by the attending physician to initiate didazinin treatment per routine practice.
* Be able to undergo polysomnography (PSG) monitoring.
* Be conscious, capable of normal communication, and able to complete sleep diaries independently.
Exclusion Criteria:
* Have Parkinson-plus syndromes, secondary parkinsonism, or other non-idiopathic Parkinson's disease.
* Have used benzodiazepine sedative-hypnotics within 7 days prior to enrollment.
* Have other significant comorbidities, such as malignant tumors, or clinically significant impairment of cardiac, hepatic, or renal function.
* Have severe obstructive sleep apnea (OSA), chronic obstructive pulmonary disease (COPD), respiratory insufficiency, or myasthenia gravis.
* Have known hypersensitivity to any component of didazinin.
* Have moderate-to-severe depression or anxiety, defined as a Hamilton Depression Rating Scale (HAMD) score ≥25 or a Hamilton Anxiety Rating Scale (HAMA) score ≥29.
* Have a history of substance abuse (e.g., drug addiction or alcohol dependence).
* Have a history of epilepsy, schizophrenia, bipolar disorder, developmental delay, or cognitive impairment.
* Be pregnant or breastfeeding.
* Be unwilling or unable to comply with scheduled follow-up visits.
* Have any other condition that, in the investigator's judgment, would make the subject unsuitable for participation (e.g., anticipated inability to complete follow-up within 14 days, or concurrent use of other medications that may substantially interfere with sleep assessment and cannot be withdrawn).
