Being suspicious all the time may be caused by the following diseases: First, the problem of depression, patients may have very low self-esteem, self-blame, and at the same time be sensitive to other people’s words and actions, such as sadness, others’ every move they are particularly concerned about, repeatedly thinking about what is the meaning behind other people’s words and actions. Second, the problem of schizophrenia, patients with schizophrenia are prone to symptoms of delusions, especially being particularly sensitive and suspicious of other people’s words and actions, appearing paranoid, such as suspecting that other people are talking about themselves behind their backs, saying bad things about them, or suspecting that someone is trying to harm them. Third, it may be caused by alcohol consumption or organic brain diseases, such as Alzheimer’s disease, especially after drinking alcohol is easy to appear sensitive, paranoid problems, especially jealous delusions, a common problem is that patients who have been drinking for a long time always suspect that their wives have an affair. Fourth, the problem of personality disorders, such as some paranoid patients are prone to sensitivity, paranoia, always suspecting that someone is targeting themselves, suspecting that the leader wants to harm them. But the symptoms of sensitivity and paranoia in these people do not generalize, but are very systematic. If it is a person who does not understand the situation, he may also identify with his sensitive and paranoid problems, and the above reasons are more common.