Healthy task initiation requires the prefrontal cortex to send an action signal to the motor cortex. In ADHD, this "go" signal is weak due to insufficient dopamine and norepinephrine. When confronted with a high-friction task, the brain relies on emotion to fill the gap.
Unfortunately, the emotion it uses is fear. The amygdala, the brain's primeval threat-detection center, senses the massive cognitive overload and 'hijacks' the prefrontal cortex. It literally shuts down your logical thinking center and initiates the fight-flight-or-freeze protocol. Procrastination is the 'flight' (escaping into a video game), and the couch-lock is the 'freeze' (sitting in silent panic).
Additionally, 'Time Blindness' removes the logical timeline. The ADHD brain does not process "This is due in three days" as a meaningful metric. The event is either happening 'Now' or 'Not Now.' Because there is no immediate crisis, the brain refuses to dispense the adrenaline required to bypass the dopamine deficit. The paralysis will maintain its grip until the 11th hour, when the 'Not Now' suddenly violently shifts into 'Now,' triggering a massive adrenaline dump.
