In all cases, dependence is a lack of independence. Dependence is leaning on someone else to provide support. Like many terms in psychology its meaning is clearest when the behavior it describes is extreme. Both dependence and independence can refer to normal and healthy personality qualities or to deviant and unhealthy qualities. We see unhealthy dependence when people lean on others for activities they can or ought to be able to do for themselves, when they try to maintain a relationship through weakness rather then through a more egalitarian interdependence, or where they are tuned into the evaluative responses of people and are so afraid of being rejected by others that they cannot assert themselves or act aggressively.
Independence develops from prior dependence and is probably related to self-confidence.
Independence in achievement behaviors results from learning that one can accomplish by oneself, can rely upon one's own abilities, can trust one's own judgment, can become invested in a task for its own sake. Similarly, healthy interdependent interpersonal relationships seem to call upon the ability to trust the other person to come close, to be dependent, to love, and even to reject. Failure to achieve independence can result from numerous experiences of frustration. Continuing dependence results from frustration of attempts to be independent or the continuous reinforcement of dependent behaviors. I have children in mind especially.