Therapeutics mimicking BDNF or therapies that inhibit or potentiate TrkB signaling may lead to uncontrolled growth effects (e.g., axon sprouting, tumor growth, or cancer cell migration), epileptic seizures and excitotoxicity, or unwished stimulation of long-term changes in synaptic plasticity, for instance, in circuits underlying addiction, reward behavior, or fear and anxiety control. Here, BDNF is linked to Anxiety.