Antipsychotics are now classified as: typical antipsychotics and atypical antipsychotics, also known as first-generation antipsychotics and second-generation antipsychotics Mechanism of action: They mainly act on various neurotransmitters in the central nervous system, such as DA, 5-HT, NE, ACH, etc., and affect human mental activities by influencing neurotransmitters. Indications: Various psychomotor excitations, hallucinations and delusions, thought disorders, emotional and behavioral disorders. Dosage: The dosage forms are tablets, injections, and long-acting injections, and the most commonly used is tablets; no matter which drug is chosen, we must understand the therapeutic range of this drug, that is, the effective dose range, the dose is insufficient to achieve the therapeutic effect, the dose is too high, side effects are likely to occur, affecting the patient’s compliance with the medication, and we must also take into account the individual differences of patients; antipsychotics start with a small dose and gradually increase to the therapeutic amount. The starting dose for elderly patients should be lower, such as risperidone, which generally starts at 1 mg per day, and 0.5 mg per day for the elderly, such as olanzapine, which generally starts at 5 mg or 10 mg per day, and may start at 2.5 mg per day for the elderly. The starting gradual dose increase is to reduce or avoid side effects of the drug.