Jealousy is natural. We're wired to compete. Good stuff, sunfyre7896! Insecurity is a problem, though. If you're comparing yourself to others because you feel worthless, that's a problem. If you're comparing yourself to others because you feel good about yourself and you know you are capable of more, that's okay. I owe my marriage to jealousy--we were friends, but we both realized we couldn't stand see the other involved with anyone else!
In my point of view, jealousy isn't definitely a mental health problem. This is one of natural human characteristics.
Jealousy isn't a mental problem, but what consequences jealousy has on your person will probably lead to bitterness and hate.
The best answer so far in my opinion. Jealousy is a disease imo. Most of the time the pain is felt by others who are in the circle of the one with the problem. I also think it definitely reflects mental instability. I love awesomenyn's reply because his definition couldn't be closer to fact imo. Some people are just naturally jealous of many things and some people allow themselves to fall into an isolated jealous stage per a unique event. So there is a difference between individuals that adopt the disease jealousy.
Jealousy is an emotion mixed with personality. Kind of like an attack on the Ego. Jealousy can get out control and produce very extreme toxic behaviour which can lead to bad health issues aswell as social and psychological. Then there is very mild form of jealousy which most can control and even makes them want to improve in themselves that which they are jealous about.
Yes, jealousy is a curse and sickness, reflecting your true inferiority fear. To cover up all inferiority issues a person should modify thr own mistakes instead of being jealous.