Who is Dr. Hornicker from The Virgin Suicides and what is their importance?

Dr. Hornicker is a reputed psychiatrist who works for the local hospital. He is a minor character for which no physical description is provided. Following Cecilia's first suicide attempt, which he diagnosed as a cry for help, he tries to counsel the family into providing a more open environment for the girls. This suggestion is ignored by Mrs. Lisbon. After Cecilia's death, he concludes that the remaining sisters are suffering from post-traumatic stress and warns that suicides are often repetitive within families. The final pages of the novel present Dr. Hornicker's analysis of the event, but this time the reasoning is flatly rejected by the narrators. They consider his diagnostic typical of the over-rationalization of the scientific community in reaction to traumatic events.