Freud proposed that personality develops through five different psychosexual stages, where the libido (sexual energy) is focused on different parts of the body. If a child experiences frustration or overindulgence during a stage, they may become fixated, leading to long-term personality traits. For example, fixation at the oral stage (0-18 months) due to overindulgence, such as prolonged breastfeeding, may result in traits like gullibility and neediness in adulthood