Answer:
The above stated all the terms are the mental stress level and illness. It is categorized by doctor or some other neurological expert. It happens due to dependence on drug or some situations or any disease.
Explanation:
Mental illness and chemical dependency are due to the intake of some drug or some other chemical. When a patient is habituated for any drug or some other medicine, he gets addicted to the drug and comes in the category of mental illness. Substance abuse and mental illnesses another mental status of a patient in which he doesn't behave normal as compared to other person.
All the above stated conditions are mental conditions or abnormality of the patient. From the past to till now we have seen several cases and it happened in the past and during the course of time.
