Final answer:
Chronic loneliness or social isolation results in excess amounts of the hormone cortisol, which is involved in stress responses and can have negative health effects when levels are elevated for long periods.
Step-by-step explanation:
The hormone found in excess amounts when studying individuals experiencing chronic loneliness/social isolation is cortisol. Cortisol is a steroid hormone that is released in response to stress and low blood-glucose concentration. It is involved in the regulation of metabolism, immune response, and stress responses. Chronic loneliness can be a form of prolonged stress, which can lead to an elevated cortisol level. The overexposure to cortisol can disrupt various bodily systems, leading to a variety of health issues.