Complex is a set of emotionally charged thoughts, ideas, and memories that are often unconscious and can significantly influence a person's behavior, feelings, and perceptions.

Complexes develop from experience, especially during childhood, and can have a profound psychological impact on an individual.
Complexes can be either negative or positive. For example, an inferiority complex is a condition in which a person feels less worthy or not good enough compared with others. This can lead to low self-esteem, social anxiety, and other emotional problems. In contrast, a superiority complex can cause excessive self-confidence and disregard for one's own shortcomings.

Complexes play a key role in psychoanalysis and depth psychology. They are often analyzed in therapy because understanding and working through complexes can help treat psychological problems and improve overall mental health.

Complexes can manifest in a person's behavior and reactions in certain situations. For example, a person with an inferiority complex may avoid social situations or react with excessive sensitivity to criticism. Working through complexes often involves psychotherapeutic methods aimed at recognizing these hidden patterns of thought and changing reactions to external stimuli.