Is there a phobia or an unusual clinical behavior for person who writes notes constantly?

Graphodermatitis or Graphodysphoria:

Excessive writing or the habit of writing excessively (particularly repetitive or prolonged) is commonly associated with graphodermatitis, a rare psychological disorder characterized by an abnormal fear of writing. This abnormal fear can manifest in various ways, such as the repetitive formation of certain letters or symbols or even in avoidance of writing activities altogether. This fear is also associated with feelings of intense anxiety, discomfort, or even physical symptoms like excessive sweating or hand trembling when the individual is required to write. For someone with graphodysphoria, the act of writing can become a distressing and overwhelming task. In severe cases, this phobia may impact a person's ability to complete written tasks necessary for work, school, or personal communication, leading to significant impairment and distress in daily life.