Urbanicity and familial liability interact and influence auditory verbal hallucinations in first-episode schizophrenia patients

In this study, we tested whether proxy genetic risk (defined as positive family history of schizophrenia in first- and second-degree relatives) and the level of urbanicity interact and influence the expression of auditory verbal hallucinations (AVH) in first-episode schizophrenia patients. We recruited 112 first-episode schizophrenia patients with age 29.24 ± 6.63 years old. The lifetime occurrence of AVH was also assessed using the The Operational Criteria for Psychotic Illness (OPCRIT), which includes the following categories of AVH: thought echo, third person auditory hallucinations, running commentary voices, abusive/accusatory/persecutory voices and other (nonaffective) auditory hallucinations. Hallucinatory behavior on the day of recruitment was evaluated using the P3 item of the Positive and Negative Syndrome Scale (PANSS). Our results show a significant effect of the interaction between family history of schizophrenia (i.e., genetic liability) and current place of residence on the total number of AVH categories (F = 4.41, p = 0.038) and the PANSS P3 item score (F = 4.21, p = 0.042). The implications of the findings are discussed within an epigenetic framework and in relation to the Differential Susceptibility Hypothesis (DSH), which states that individuals who are most at risk to adversity will most likely benefit from supportive environments. An integrative therapeutic approach is suggested as a means to improve the quality of life of first-episode schizophrenia patients living in urban environments.