Sigmund Freud was a psychologist that studied the Conversion disorder .
It is thought that symptoms arise in response to stressful situations affecting a patient 's mental health and Conversion disorder is considered a psychiatric disorder in the Diagnostic and Statistical Manual of Mental Disorders fifth edition ( DSM-5 ) .Diagnostic and Statistical Manual of Mental Disorders , Fifth Edition , American Psychiatric Association Formerly known as `` hysteria '' , the disorder has arguably been known for millennia , though it came to greatest prominence at the end of the 19th century , when the neurologists Jean-Martin Charcot and Sigmund Freud and psychiatrist Pierre Janet focused their studies on the subject .