Stabilization of the internal structure of persistent auditory verbal hallucinations in schizophrenia

Numerous studies have been conducted to investigate the phenomenological characteristics of auditory verbal hallucinations in schizophrenia. Difficulties in understanding the clinical significance of auditory verbal hallucinations may be attributed to the changes in symptom structure over the long-term course of the illness. The purpose of the present study was therefore to investigate the longitudinal changes in the phenomenological dimensions of auditory verbal hallucinations in patients with schizophrenia.

Using the Psychotic Symptom Rating Scales-Auditory Hallucination Subscale, 40 patients meeting DSM-IV criteria for schizophrenia (drug-naive first-episode schizophrenia, n=21; and drug-free chronic schizophrenia, n=19) who reported persistent auditory verbal hallucinations were assessed before the initiation of antipsychotic treatment and after 6 months of treatment. To detect the changes in underlying clusters of phenomenological variables, hierarchical clustering and multidimensional analysis were performed.

The phenomenological variables of auditory verbal hallucinations formed two main clusters with 6 month treatment: emotional and cognitive. Physical characteristics failed to indicate a stable cluster. Psychosocial disruption, which initially formed a cluster with cognitive variables, congregated with emotional variables at 6 months. Subgroup analysis indicated that the cluster structure of the first-episode group showed more dynamic changes than did that of the chronic schizophrenia group.

Phenomenological variables characterizing persistent auditory verbal hallucinations can be differentiated into emotional and cognitive clusters with achievement of symptom stabilization, and the changes in physical characteristics may not be the sole sign of clinical improvement.