Disordered and peculiar behavior is one of the clinical manifestations of mental disorder associated with intracranial tumor. Mental disorder associated with intracranial tumor refers to the mental disorder associated with the invasion of brain parenchyma by intracranial tumor and compression of adjacent brain tissues or cerebral blood vessels, resulting in destruction of brain parenchyma or increase of intracranial pressure, and about 40% to 100% of patients suffering from intracranial tumor can develop mental symptoms. How to check behavior disorder and peculiar? The clinical manifestations are diverse, sometimes the symptoms are not typical in early stage, and when the basic features of tumor are available, the condition is often advanced. Brain tumor develops slowly, the first symptoms are increased intracranial pressure such as headache, vomiting and neurological localization symptoms such as muscle weakness, epilepsy, etc. After weeks, months or years, the symptoms increase and the condition worsens, and the condition of acute onset can deteriorate suddenly within hours or days and fall into paralysis In acute cases, the disease may deteriorate suddenly within a few hours or days, leading to paralysis, coma, diffuse acute cerebral edema, or death due to sudden obstruction of cerebrospinal fluid circulation pathway by the tumor (cyst), resulting in a sharp increase in intracranial pressure and brain herniation. 1.Somatic symptoms Headache, nausea and vomiting, optic disc edema and vision loss are the three main manifestations of increased intracranial pressure caused by brain tumor. Headache: The headache is episodic at the beginning, mostly in the morning and evening, and then increases during the day. (2) Vomiting: It occurs mostly in the early morning or on an empty stomach, and it is more common when the headache is severe. (3) Optic disc edema: Optic disc edema appears early in subcurtain and midline tumors, while slow-growing tumors on the curtain appear later or even do not occur. After the optic disc continues to edema for a long time, optic nerve atrophy may occur secondary to optic disc pallor and vision loss, suggesting that the optic nerve has secondary atrophy and even blindness. The general psychiatric symptoms of intracranial tumor include blurred consciousness, amnesia syndrome, dementia and less common bipolar-like and schizophrenic-like psychosis. ①Blurred consciousness: Blurred consciousness is a general symptom of brain tumor, which can be manifested in different forms and variability, and can be seen in any part of rapidly developing tumor, which belongs to acute cerebral organic syndrome, difficulty in understanding and responding, slow action, slow reaction, dullness, drowsiness, inattention, emotional indifference, disorientation, and also can occur as blurred consciousness or coma attack. Amnesia syndrome: Patients may show early decompensation or amnesia of recent events, and the memory of past experiences cannot be recaptured, or even new memories are distorted, but generally immediate memory can remain relatively good, and the disease may develop disorientation, paracrine amnesia and Korsakoff syndrome with fictitious phenomena. Dementia: Patients with slow-growing, long-standing brain tumors may exhibit dementia, which is characterized by deficits in calculation, comprehension, and judgment, and this symptom may be detected early due to inability to adapt to work. Schizophrenia-like psychosis: Although intracranial tumors can induce schizophrenia, the possibility of concomitant tumors exceeds the expected opportunity, indicating that there may be specific brain tumors that can cause schizophrenia-like psychosis. The perceptual disorder often appears together with behavioral abnormalities. ⑤ Affective disorders: intracranial tumors with affective disorders are less common, but generally they are usually seen as indifference and depression, indifference to external things, dullness and lack of initiative. It is also seen as crying and laughing for no reason, mood instability, irritability, depression, crying, irritability, anxiety; especially temporal lobe tumor, intracranial tumor with manic episodes is rare, frontal lobe tumor patients show childish, occasionally see euphoric symptoms. (6) Psychotic reactions occurring on a psychogenic basis: Whether it is psychotic reactions occurring due to the patient’s attitude toward intracranial tumors or transient psychotic reactions after surgery, there is a psychogenic basis, and it is also related to the patient’s premorbid personality. Compensatory behaviors for organic defects are nonspecific and are seen in brain injury and other organic brain diseases, see the chapter on mental disorders associated with craniocerebral injury. (7) Personality changes and behavioral abnormalities Patients show a lack of initiative, reduced interest, lazy life, passive behavior, lack of neatness, lack of shame, no initiative to eat, sitting or bedridden, silent, or even similar to wood stiffness; some may shout, run around, or collect obscene objects, personality changes, behavioral abnormalities and intelligence changes often appear at the same time. Auxiliary examinations include cranial X-ray, brain CT, MRI, cerebral angiography, brain ultrasonography, etc. Among them, brain CT and MRI are the most valuable examinations for brain tumor diagnosis, with a positive rate of more than 95%, and they are of great value in defining the location, size and scope of the tumor. In recent years, positron emission tomography (PET) has been applied to show tumor images and local brain cell functional activity. Neuropsychological examination must be done in order to grasp the function around the tumor in order to provide a baseline for surgery and protect the patient’s brain function at the same time.