Amplification Loop

An amplification loop is a self-reinforcing cycle in which changes in one part of a system intensify changes in another part, causing the original change to grow stronger over time. In bipolar disorder, amplification loops often involve interactions among sleep, circadian rhythms, reward sensitivity, stress, and mood. A burst of energy may lead to reduced sleep, and reduced sleep can increase reward-seeking and emotional intensity. These changes can further reduce sleep and increase activation, creating a cycle that accelerates toward hypomania or mania. Similar loops can operate in the opposite direction, contributing to depression. Amplification loops help explain why bipolar episodes can sometimes build gradually and then seem to gather momentum. They also help explain why interventions that target a single part of the cycle — such as stabilizing sleep schedules, reducing stress, or moderating goal-directed activity — can have effects that extend throughout the entire system. Also see Episode Threshold, Sensitization, Kindling Hypothesis, and Positive Feedback Loop.