Answer:
because of the hormone known as the gifting hormone which is realeased whenever something good happens but in small amounts. but that isn't the case when it comes to drugs as the body releases huge amount of the hormone which stays between the synapses of neurons for longer periods of time this gives the addicted person that feel of joy. sadly enough the person gets used to this feeling which makes him increase the dosage. he falls into the same trap again and again until it becomes an addiction almost impossible to escape
Explanation:
note: almost the same thing happens with other addictions such as maturation and alcohol addiction except its not as danger as drugs
