The basal ganglia (specifically the striatum) is the brain's 'habit center.' In a healthy brain, as a behavior is repeated, control shifts from the conscious, energy-hungry prefrontal cortex to the efficient, automatic basal ganglia. This shift requires stable dopamine signaling to "cement" the pathway.
Because the ADHD brain suffers from rapid dopamine decay, the "cement" never dries. The behavior never successfully transfers to the automatic basal ganglia. Therefore, brushing your teeth or following a morning schedule requires the exact same massive, conscious effort from the prefrontal cortex on Day 100 as it did on Day 1. The "efficiency" of a habit is never achieved.
Simultaneously, the brain's 'novelty reward system' goes into withdrawal. The human brain is evolutionarily wired to seek out new information to survive. The ADHD brain is hyper-tuned to this setting. A rigid Tuesday that looks exactly like a rigid Monday is registered by the nervous system as a deprivation environment, triggering task avoidance and seeking out distractions that offer high chemical yields.
