An adult "stuck" at a young age is often experiencing arrested emotional development or involuntary regression, where trauma or deep emotional wounds freeze development at that age.

 An adult "stuck" at a young age is often experiencing arrested emotional development or involuntary regression, where trauma or deep emotional wounds freeze development at that age. This can cause childish behavior patterns to reappear during times of stress, trauma, or lack of autonomy, requiring therapy to address the root causes. 

 Key aspects of this phenomenon include:     

 Trauma Response: Unhealed trauma, particularly from childhood, can prevent emotional maturity, causing a "freeze" response where the individual reacts to life's challenges from the emotional capacity of that earlier age.     

Age Regression triggers: These incidents often occur when the individual feels unsafe, overwhelmed, insecure, or re-traumatized, leading to behaviors that resemble a younger child.     

Dependency and Responsibility: The individual may struggle with self-trust, autonomy, and accepting responsibility for their life, often relying heavily on others for support.  

Treatment: While it can feel hopeless, specialized therapy is necessary to help the individual process these "stuck" emotions and build tools to function as a mature adult.   If this behavior is sudden or accompanies memory loss, it could also be a symptom of a neurological condition, such as dementia.