The answer is : Tar
Tar is some sort of residual substance that we commonly found in tobacco products, which could cause the symptoms you've mentioned above
not only that, Tar is a highly carcinogenic substance, which mean that it generate high risk of cancer it get into our system
HUMAN HAS A HEART WHILE A WORM HAS 5. A WORM DOES NOT WALK WHILE A HUMAN DOES. THEY BOTH ARE ORGANISMS.
You can say depression or health benefits