Lack of Confidence

Lots of people suffer with the occasional crisis of confidence, but for some people, lacking confidence almost becomes ingrained in their personality. Self-confident people have a positive and realistic perception of themselves and their abilities, whereas people who lack self-confidence generally feel inferior to others and are doubtful of their self-worth. They tend to isolate themselves and over-conform because they mistrust their own judgement and abilities.

People who suffer from a lack of self-confidence often hamper their own progress in life by not attempting to try anything new. If the lack is severe, sufferers will not try to succeed in anything because they think they will fail if they do. They suffer severely from feelings of inferiority to others around them. Some people with confidence issues are secretly aware that they have potential ability, but refuse to acknowledge it, thereby avoiding the risk of failure.

http://www.nelsonsnaturalworld.com/en-gb/uk/a-z-of-ailments/emotional-health/lack-of-self-confidence/