why does a person suffers from it?
Drug poisoning and lack of oxygen.
Coma
Many types of problems can cause a coma. Forty percent of comatose states result from drug poisoning. 
what is durian? It is the fruit of from tree species belonging to the genus "Durio". where is it found? Borneo and Sumatra. what are its types? Mon Thong, Chantaburi No. 1, Chantaburi No. 3, D24 and XO. is it nutritious? Yes, it contains proteins, carbohydrates, vitamin C, and manganese. does it have a smell? Yes, an unusual and disagreeable odour. can you name any other two food items which contains the mentioned vitamin? Guava, broccoli. which disease is caused due to its deficiency? Scurvy. does its intake causes any side effects? Nausea, abdominal cramps and diarrhea. any other cause of the mentioned disease other than deficiency? Malnutrition and poor dietary choices. how is it treated? By preventing dehydration, low blood sugar, low body temperature, infection, correct electrolyte imbalances and micronutrient deficiencies. was any trial conducted in relation to this? Yes, human trials were conducted to study scurvy. can you name any other disease that is caused due to the former cause you mentioned just above? Hypernatremia. what are its symptoms? Thirst, seizures and comas. from where does the third one derived its name? Greek.
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Coma [SEP] Causes
Many types of problems can cause a coma. Forty percent of comatose states result from drug poisoning. Certain drug use under certain conditions can damage or weaken the synaptic functioning in the ascending reticular activating system (ARAS) and keep the system from properly functioning to arouse the brain. Secondary effects of drugs, which include abnormal heart rate and blood pressure, as well as abnormal breathing and sweating, may also indirectly harm the functioning of the ARAS and lead to a coma. Given that drug poisoning is the cause for a large portion of patients in a coma, hospitals first test all comatose patients by observing pupil size and eye movement, through the vestibular-ocular reflex.