Can diseases really be caused by stress and "nerves"?

Stress and "nerves" are physiological phenomena, in particular, manifesting themselves at the endocrine level, that is, they are accompanied by the production of hormones. Hormones are distributed throughout the body and affect a wide variety of organ groups. Therefore, the occurrence of diseases under stress and strong feelings is not magic, but a completely understandable physiological fact.

For example, prolonged monotonous stress is one of the factors in the development of hypertension. With it, norepinephrine is released in large quantities (this is a neurotransmitter, not a hormone, but in this case it is not so important), which has nowhere to go, so it spasms the microvessels, which increases pressure. Over time, the effect becomes permanent. Hypertension acts as a risk factor for heart attack, so it turns out that stress leads to heart attack.

They can and are called. And even those that are not caused by a negative emotional background worsen when present. Such diseases are called psychosomatic and there are many of them. They are engaged in psychosomatic medicine. There are also various theories in psychiatry that explain the occurrence of schizophrenia, roughly speaking, by stress.

As you know, any stress is a blow to the body and, as a result, a drop in immunity. Also, if you are often nervous, stomach problems develop, with the nervous system itself. So technically, yes, nerves and stress can cause gastrointestinal diseases, or provoke a common cold, or some kind of chronic disease.