Fear of being alone may be caused by the following diseases: 1, the problem of depression, depression is easy to become depressed mood, happy, pessimistic, negative, low self-esteem, self-blame, self-guilt, feel that they dragged down the family, this time is easy to be sensitive, especially when lonely is easy to think more, and even appeared some problems love to drill the corner. This time it is easy to appear afraid of being alone, afraid of loneliness, loneliness. 2, may be the emergence of anxiety disorders, anxiety patients are easy to mental tension, fear, fear, always worried, quiet. It may also be accompanied by somatic symptoms, such as headache, dizziness, nausea, vomiting, or with behavioral manifestations, such as fidgeting and walking back and forth. Patients with anxiety disorders may be afraid of being alone, especially when they are afraid of being alone with nervousness and anxiety.3. It may also be caused by some other diseases, such as Alzheimer’s disease. Patients with Alzheimer’s disease may become especially afraid of loneliness and isolation due to memory loss, and always need people’s company, etc. These reasons are more common.