Prevalence and relationship to delusions and hallucinations of anxiety disorders in schizophrenia

We investigated the prevalence of anxiety disorders in a sample of individuals with chronic schizophrenia, controlling for anxiety symptoms that may be related to delusions and hallucinations, and the possible differences in clinical variables between the groups. Individuals with a diagnosis of schizophrenia and able to give informed consent were rermited from the community. The Mini International Neuropsychiatric Interview (MINI) was administered to both confirm the DSM-IV diagnosis of schizophrenia and screen for comorbid anxiety disorders. If a comorbid anxiety disorder was found, its relation to the individual's delusions and hallucinations was examined. Clinical rating scales for schizophrenia were administered as well as rating scales for specific anxiety disorders where appropriate. Overall, anxiety disorders ranged from 0% [for Post Traumatic Stress Disorder (PTSD)] to 26.7% [for generalized anxiety disorder (GAD) and agoraphobia without panic] with lower rates when controlled for anxiety symptoms related to delusions and hallucinations. In investigating clinical variables, the cohort was initially divided into schizophrenics with no anxiety disorders and those with an anxiety disorder; with further analyses including schizophrenics with anxiety disorders related to delusions and hallucinations and those with anxiety disorders not related to delusions and hallucinations. The most consistent difference between an the groups was on the PANSS-G subscale. No significant differences were found on the remaining clinical variables. Comorbid anxiety disorders in schizophrenia can be related to the individual's delusions and hallucinations, though anxiety disorders can occur exclusive of these positive symptoms. Clinicians must be aware that this comorbidity exists in order to optimize an individual's treatment. (C) 2003 Wiley-Liss, Inc.