This issue of CNS Spectrums explores the boundaries and relationship between anxiety and psychosis from various perspectives. Anxiety may be conceived as being secondary to psychosis, or psychosis emerging from an anxiety disorder. Anxiety might also be a symptom, or part and parcel, of a psychotic illness. Finally, pharmacologic treatment of psychosis might precipitate an anxiety disorder, or psychopharmacologic approaches to anxiety disorders might precipitate psychosis. Thus, the relationship between these two symptom clusters may be complex and multidetermined.

First, I would like to thank Stefano Pallanti, MD, of both the Institute of Neurosciences at the University of Florence Medical School and the Mount Sinai School of Medicine, for defining the challenge, assembling an international cohort of experts, and guest editing this issue.

In this issue, Rossi and colleagues present original research derived from a study of 400 inpatients that examines the pattern of comorbidity among obsessive-compulsive personality disorder (OCPD) and other personality disorders. Of interest, the highest co-occurence of OCPD is with the cluster A disorders (paranoid and schizoid)—the “odd” cluster.

Pallanti and colleagues describe the development of social phobia in 12 patients with paranoid schizophrenia during clozapine treatment. Two thirds of these patients had significant improvement of social phobic symptoms with fluoxetine augmentation of clozapine. This new observation is certainly reminiscent of the induction of obsessive-compulsive symptomatology with atypical neuroleptic treatment in schizophrenia.