True but partially. It might not insecurity alone rather it can be jealous, fear, lack of trust on oneself. Being human, one expects attention towards them and it happens that if someone stopped talking or paying attention to one, they start feeling they left alone and starting evaluating contexts. Its a natural tendency to feel so.
However, once he/she feels to work on what exactly it takes them or think out of box, they will have no time to realise what others think of them.
Thanks & Regards