Chronic effects refer to the long-term impact or consequences of a particular stimulus or exposure on an individual's health or well-being. This could include the effects of drug use, exposure to environmental toxins, or lifestyle factors over an extended period of time. Researchers studying chronic effects typically monitor individuals over a significant period to track changes in health outcomes or behaviors. Studying chronic effects is important for understanding the long-term implications of certain exposures and can help inform public health policies and interventions.