Introverts do sometimes have some mental illness and mental health issues just like extroverts do.
However introversion is not a mental health condition itself but instead is a personality trait.
Being an introvert means that you sometimes prefer socializing differently than extroverts although some introverts don't like socializing at all.
Typical introverts like to spend time alone or spend their social time with small groups rather than large ones, which may feel overwhelming and draining to them.
They also tend to want to discuss “real” issues rather than making small talk.
The traits of extraversion and introversion are a central dimension in some human personality theories.
The terms introversion and extraversion were introduced into psychology by Carl Jung, although both the popular understanding and current psychological usage vary.
An introvert is a person with qualities of a personality type known as introversion, which means that they feel more comfortable focusing on their inner thoughts and ideas, rather than what's happening externally.
They enjoy spending time with just one or two people, rather than large groups or crowds.