Any consistent, inescapable, or repeating negative stimuli, such as constant pain or prolonged starvation, will shift a nematode brain into a state of chronic stress. Chronic stress isn’t all that different from acute stress; stress hormones and opioids remain elevated, chronically inhibiting digestion, immune response, appetite, and reproduction. But chronic stress differs from acute stress in at least one important way: it turns off arousal and motivation.
