Sociopaths

Sociopaths are infrequent in the society, but it's normal to hear stories of people who suffered because of them from time to time.

It's really important to notice the strange signs which can mean of mental disorders such as aggressive behavior or lack of empathy.

Not everyone is a danger. It's even likely you know someone with a mental illness. But if you notice violent behavior it's better to run for your life, or at least, to stay away from him or her.

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I made a few grammatical changes above in green. Depending where you intended to submit this writing, it may also be helpful to soften the tone. Many people are sensitive to the topic of mental health, so using phrases such as "mental health issues" or "mental illness" might appeal to a wider audience compared to "mental disorders". Also, words like "strange signs of mental disorders" and "it's better to run for your life" could come across as derogatory. Other possible ways to express similar ideas could be, "symptoms of mental illness" and "it's better to leave that situation and find help,". These are only my suggestions about tone. The way you wrote it is not incorrect.