The word 精神病 is formed by combining three meaningful building blocks: 精 (essence/vitality), 神 (spirit/consciousness), and 病 (illness/sickness). The first two characters, 精神, together conceptually mean "spirit" or "mind", referring to one's mental and psychological faculties. This compound is then directly modified by 病, meaning "disease", to create the complete concept of a "disease of the mind" or "mental illness". The formation is a logical, meaning-based construction where the core idea of "mind" is directly linked to the state of being "ill".