Patients with Parkinson’s disease may experience psychotic symptoms such as hallucinations, euphoria, and delusions in the late stages of the disease. Usually hallucinations occur, which manifest as seeing or hearing things or sounds that are not even there. For example, some patients may feel that there is always a figure following him during treatment; or see people or animals that do not exist; or always suspect that their partner is having an affair, etc., when these things do not exist at all. Or they may manifest as emotional agitation, unprovoked tantrums, etc. These psychiatric symptoms usually occur 10 years or more after the diagnosis of Parkinson’s disease, and if they appear early in the disease, it is important to consider whether there is a primary psychosis or Parkinson’s syndrome. Anti-Parkinson’s disease medications can also cause psychiatric symptoms, most commonly benzhexol hydrochloride and amantadine. Therefore, when a patient develops psychiatric symptoms first consider gradually reducing or discontinuing anticholinergics, amantadine, sildenafil (Midolpir), DR agonists (Senfuro, Tysudar) in sequence, and if the patient is still symptomatic, gradually reduce the compounded levodopa dose, usually by about one-third of the total dose. For those who are ineffective with medication adjustment or unable to reduce the anti-PD medication due to heavy symptoms, the atypical antipsychotic drug clozapine can be added under the guidance of a psychiatrist or neurologist, which is inexpensive and very effective. In addition, the drug has central and peripheral anticholinergic effects, equivalent to the effects of Antanomics, so its application is appropriate for the treatment of Parkinson’s disease with psychiatric symptoms. The recommended dose of clozapine is 5 mg per tablet, 6.25 mg per day, and is usually given as half a tablet three times a day for one to three days. Some patients may experience drowsiness or dizziness during the course of the drug, which may disappear the day after the drug is administered or after the drug is stopped. A serious side effect of clozapine is granulocytopenia, which has a probability of about 0.38%, and the white blood cell count should be tested during the first 6 months of treatment. There is also a new antipsychotic drug called “quetiapine” that is effective in relieving drug-induced psychotic symptoms. Antipsychotic medications may worsen the symptoms of Parkinson’s disease, but the two drugs mentioned above are relatively safe.