When it comes to Parkinson’s disease, people pay more attention to the impact of the disease’s motor symptoms, while the mental symptoms accompanying the disease itself are often not enough attention, in fact, in the later stages of the disease mental symptoms on the quality of life is even more serious than the motor symptoms. The manifestation of PD mental symptoms 1, depression The type of depression in PD can be divided into three categories: reactive depression, endogenous depression, fluctuating depression. Reactive depression is a kind of reaction when the patient learns about the disease; endogenous depression is a symptom of PD itself, with the basis of the relevant neurological structural lesions involved in the PD disease itself, and this type of depression can appear in all stages of the PD course; fluctuating depression is easy to be ignored. For PD patients, not only can motor symptoms fluctuate, but depression can also fluctuate; it is part of the end-of-agent phenomenon, and the use of measures targeting motor fluctuations is equally effective in fluctuating depression. Compared with ordinary depression, depression in PD is not fundamentally different, but there is a difference in the proportion of symptom occurrence between the two. In terms of affective apathy, delusions and suicide attempts, PD-related depression has a lower incidence than ordinary depression, suggesting that depression in PD patients is predominantly mild to moderate. Another difference is that depression in PD patients is more refractory, and the efficacy of using antidepressants is not good; refractory depression accounts for 22% of PD depressed patients, while the proportion of refractory patients in ordinary depressed patients is only 10%. Depression in PD patients has a great impact on the quality of life, but the degree of attention is not enough, a survey in the UK showed that the incidence of early PD patients with depressive symptoms is very high, often prompting patients to seek medical attention, but often little attention, so that the patient’s quality of life has not been improved. 2, Anxiety The difference between the anxiety of PD patients and general anxiety patients is not large, mainly manifested as generalized anxiety, panic disorder, social terror, square terror and non-specific anxiety, compared to more patients with panic disorder. Generalized anxiety is affected by a number of factors and may be characterized by displays of affective apathy, hyperventilation, tremor, thermoregulatory disorders and autonomic impairment. Autonomic impairment and tremor tend to be more common and are more likely to be affected by motor symptoms, whereas affective apathy is not affected by motor symptoms. Emotional apathy is a mental state with reduced emotional response, which is divided into behavioral, cognitive and affective types, with the main core being lack of motivation. Cognitive apathy is characterized by lack of interest in new things and indifference to other people’s problems, which accounts for most of the cases; followed by behavioral apathy, which is characterized by lack of aggressiveness and creativity in behavior and dependence on other people’s activities; and affective apathy, which is characterized by bland emotions and lack of emotional response to objective or negative events. Emotional indifference can exist independently, or it often occurs together with depression. In addition to the above, psychiatric symptoms such as hallucinations, delusions, illusions and false perceptions of existence are also common. In addition, although the incidence of impulse control disorders is low, with the progression of the disease, the incidence of impulse control disorders in elderly patients gradually increases, mainly manifested as binge drinking and eating, hypersexuality, compulsive shopping and gambling, in addition to impulsive-compulsive behaviors, such as Punding (stereotypical, repetitive and purposeless behaviors) and Dopamine Dysregulation Syndrome, which is manifested as the compulsive overdose of anti-PD drugs. Drugs. There is a mechanism for impulse control disorders, with changes in the dopamine system, ventral striatum, and cortex seen on imaging, and gender and age also affecting the specific manifestations of impulse control disorders. Clinical medications are also relevant. Dopamine agonists may induce impulse control disorders, and smoking history, lifestyle habits, and family history may also have an impact. The neurotransmitter most closely related to depression is 5-hydroxytryptamine (5-HT), which is produced in the nucleus accumbens of the brainstem. It has been found that in the cerebrospinal fluid of PD patients with depression, the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HTAA), the dopamine metabolite homovanillic acid (HVA), and the norepinephrine (NE) metabolite 3-methoxy 4-hydroxyphenylethyleneglycol (MHPG) are reduced. Other classical studies have shown reduced amino acid decarboxylation in the nucleus accumbens and decreased metabolism in the frontal orbital surface and caudate nucleus (DA, 5-HT projection pathway to the neocortex). Resting-state fMRI studies at West China Hospital have shown that depressed patients with PD have enhanced localized spontaneous neural activity in the orbitofrontal region and reduced functional integration within the prefrontal-limbic network system. Several other pathologic studies have found reduced levels of norepinephrine neurotransmitters in different parts of the thalamus compared with controls. Another study on patients with PD apathy showed that PD apathy was associated with reduced functional linkage of frontal striatal loops, especially in the left hemisphere, mainly involving the limbic system. This shows that there is indeed a certain material basis for psychiatric symptoms in PD patients and that psychiatric symptoms are part of PD. Third, the diagnosis of psychiatric symptoms in PD For ordinary depression and anxiety patients, scales are usually used for assessment and diagnosis. Two prospective cohort studies in foreign countries assessed the use of depression scales in PD patients and found that the sensitivity and specificity of the Hamilton Depression Scale (17 items) and the Beck Depression Scale are better if the diagnostic criteria for depression are ≥13 points. Therefore, this needs to be noted when using both for assessment. For the diagnosis of PD depression, diagnostic criteria were introduced in China in 2013: 1. primary PD diagnosed in accordance with the diagnostic criteria of the British Parkinson’s Disease Association Brain Bank or the Chinese Parkinson’s Disease Diagnostic Criteria; and 2. meeting the DSM-IV diagnostic criteria for depressive episodes. There are 4 clinical types of PD anxiety: no anxiety and depression, episodic anxiety without depression, persistent anxiety with depression, and persistent and episodic anxiety with depression. Comparison with DSM-IV revealed that the symptom spectrum of PD anxiety is not consistent with it, and the DSM-IV diagnostic criteria for anxiety may not be applicable to PD patients. Therefore, the DSM-IV criteria were not adopted when the diagnostic criteria were formulated in China, and the specific diagnostic criteria were: 1. primary PD diagnosed in accordance with the diagnostic criteria of the British Parkinson’s Disease Association Brain Bank or the diagnostic criteria of Parkinson’s Disease in China; and 2. in accordance with the diagnostic criteria of generalized anxiety, panic disorder, social phobia or obsessive-compulsive disorder of the CCMD-3 (either of these four criteria can be met). The diagnostic criteria for psychotic disorders in China were: 1. primary PD diagnosed in accordance with the diagnostic criteria of the British Parkinson’s Disease Association Brain Bank or Chinese Parkinson’s Disease Diagnostic Criteria; 2. the presence of at least one of the following symptoms: hallucinations, illusions, delusions, and false perceptions of existence; and 3. the appearance of psychotic symptoms after the onset of PD, at least 1 year after the diagnosis of PD, and in most cases, after 10 years of the diagnosis of PD. Of these, the last criterion was developed primarily to differentiate from Lewy body disease. Fourth, the treatment of psychiatric symptoms in PD There are three types of medications recommended by the current guidelines for the treatment of depression in PD. The first is the drug pramipexole, which treats PD itself, and which has definite anti-PD depressive effects and can be used for PD depression treatment (level B recommendation). The antidepressants paroxetine and venlafaxine extended-release capsules have a significant difference in efficacy when compared to placebo and can be used for PD depression treatment (Grade B recommendation). In addition, SSRI antidepressants, including escitalopram, lack sufficient evidence-based medical evidence to prove their efficacy, but due to the milder side effects of SSRI antidepressants, they can be considered for the treatment of PD with depressive symptoms (U-level recommendation); and sildenafilan also has potential antidepressant efficacy in patients with PD (U-level recommendation). There is a lack of sufficient evidence-based medical evidence for the treatment of PD with anxiety; anxiety in patients with PD is usually accompanied by depression; therefore, antidepressant treatment can improve patients’ anxiety symptoms, and benzodiazepines, such as lorazepam or diazepam, can be used for moderate anxiety (U-level recommendation). In addition, similar to the general population, SSRI medications can be used for the treatment of panic attacks, social fears, and obsessive-compulsive symptoms in PD (U-level recommendation). In terms of the treatment of PD with emotional apathy, a recent foreign trial using piribedil 300mg/d showed that it can significantly reduce PD apathy scores. It should be noted that the maximum dose of piribedil is 250mg/d, and the dose of the drug used in this study is beyond the domestic dose. Clozapine is recommended for the treatment of PD psychotic symptoms, which is effective for PD patients with visual hallucinations, delirium and other psychotic symptoms, and does not aggravate the symptoms of PD, and there are even experiments proving that it can improve the motor symptoms to a certain extent, but it has the side effect of granulocytopenia, so it needs to be regularly examined (Grade B Recommendation); in addition, quetiapine can be used for the treatment of psychotic symptoms (Grade C Recommendation). It should be noted that olanzapine, a commonly used psychiatric drug, is not recommended because it significantly aggravates extrapyramidal symptoms and does not improve psychotic symptoms in PD patients (Grade B recommendation). Recently, a new drug, Pimavanserin, which is a 5-HT 2A antagonist and has no effect on the dopamine system, was tested in a phase III clinical trial (lasting 6 weeks). The results showed that the drug can improve psychiatric symptoms in PD and does not exacerbate the motor symptoms of PD itself, which is a better effect, and the specific efficacy of the drug needs to be confirmed by further evidence-based medical evidence.