If the dreamer is the victim of kidnappers: The forces of our own fears and negative feelings are often presented as an external force or organised gang who victimise us. If such feelings are recognised for what they are, self created emotions, they lose their power. Being kidnapped also suggests loss of security or feelings of security, or someone else forcing their will on one.
Kidnapping family member or friend: Because the family member or friend is probably used in your dream to represent your memories or feelings about them see Characters and People in Dreams.
In many cases it represents feelings of your own vulnerability, that your own fears or your anxiety about being trapped is holding you hostage. Also that because you feelvulnerable you may become captured by someone else’s forceful manner of approach.
Kidnapping someone else: Influencing someone else against their will. This may of course be about oneself, referring to forcing oneself to do something that ones feelings are against.
Useful Questions and Hints:
Have you recently felt influenced by someone else or by your own anxieties?
Has anyone been bullying you or browbeat you?
Do you feel anxious about family members being badly influenced?