Primary headache and comorbidity with mood and anxiety disorders: an example of the psycho-neuro-biological loop

Although an association between primary headache and psychiatric disorders, has been recognised for over 100 years, this association has been investigated systematically only recently. The nature of this association has also been examined in recent studies. Real comorbidity implies that primary headache and psychiatric disorders are indipendent phenomena, i.e. a casual co-presence, while the frequency of their association suggests different and deeper links. Literature data show that psychiatric comorbidity in migraine and tension-type headache is very similar (88% and 85% respectively). Anxiety disorders is the most frequent association (54,9% and 52,5% respectively) followed by mood disorders (34,4% and 36,4% respectively). We discuss the available evidence on the psycho-neurobiological cascade of events possibly linking primary headache to mood and anxiety disorders.