A patient describes a sensation where he feels his arm is being moved by an external, alien force, despite his own will. This specific experience is categorized under Schneider's First-Rank Symptoms as:

Explanation

Schneider's First-Rank Symptoms include 'feelings of being controlled' or 'passivity experiences.' These are further broken down into delusional control of actions, impulses, and feelings, as well as somatic passivity. The patient feeling his arm being moved by an external force against his will directly describes delusional control of actions. Somatic passivity refers to the feeling that one's body is being acted upon or influenced by an external force, often involving physical sensations (e.g., electricity, heat, pain). While related, the specific description of an *action* (moving an arm) being controlled fits 'delusional control of actions' more precisely than the broader 'somatic passivity,' which typically involves passive bodily sensations rather than active movements being controlled.