Age effects on basic symptoms in the community: A route to gain new insight into the neurodevelopment of psychosis?

Frauke Schultze-Lutter,Jochen Kindler,Chantal Michel,Stefanie J Schmidt,Stephan Ruhrmann,Benno G Schimmelmann

doi:10.1007/s00406-018-0949-4

Abstract

Reports of limited clinical significance of attenuated psychotic symptoms before age 15/16 indicate an important role of neurodevelopment in the early detection of psychoses. Therefore, we examined if age also exerts an influence on the prevalence and clinical significance of the 14 cognitive and perceptive basic symptoms (BS) used in psychosis-risk criteria and conceptualized as the most direct self-experienced expression of neurobiological aberrations. A random representative general population sample of the Swiss canton Bern (N = 689, age 8–40 years, 06/2011–05/2014) was interviewed for BS, psychosocial functioning, and current mental disorder. BS were reported by 18% of participants, mainly cognitive BS (15%). In regression analyses, age affected perceptive and cognitive BS differently, indicating an age threshold for perceptive BS in late adolescence (around age 18) and for cognitive BS in young adulthood (early twenties)—with higher prevalence, but a lesser association with functional deficits and the presence of mental disorder in the below-threshold groups. Thereby, interaction effects between age and BS on functioning and mental disorder were commonly stronger than individual effects of age and BS. Indicating support of the proposed “substrate-closeness” of BS, differential age effects of perceptual and cognitive BS seem to follow normal brain maturation processes, in which they might occur as infrequent and temporary non-pathological disturbances. Their persistence or occurrence after conclusion of main brain maturation processes, however, might signify aberrant maturation or neurodegenerative processes. Thus, BS might provide important insight into the pathogenesis of psychosis and into differential neuroprotective or anti-inflammatory targets.

Highlights

Psychoses, in particular the schizophrenia spectrum, are considered a fundamentally neurodevelopmental disorder involving two critical time windows—early brain development and adolescence—that together produce the symptomatic manifestations of the disorder [1]
Following the main method employed to study age effects in attenuated psychotic symptom (APS) [8, 9, 11], i.e., comparing predefined age groups, and interactions of symptoms and age by regression analyses, the current study examined potential age effects in the prevalence and clinical significance of the 14 basic symptoms (BS) included in cognitiveperceptive BS (COPER) and cognitive disturbances (COGDIS) in the general population
Because the SPI-CY requires a minimum age of years for the assessment of three of the BS included in COPER and COGDIS (Online Resource 1), main analyses were conducted on the 11 BS assessed across all age groups to avoid a negative selection bias in the youngest age group

Summary

Introduction

In particular the schizophrenia spectrum, are considered a fundamentally neurodevelopmental disorder involving two critical time windows—early (perinatal) brain development and adolescence—that together produce the symptomatic manifestations of the disorder [1]. BS remain predominately private and are rarely perceivable by others, patients’ self-initiated coping strategies (including avoidance strategies and social withdrawal) in response to their BS may be observable, e.g., as negative symptoms [13]. Due to their spontaneous, immediate recognition by patients as disturbances of their own (mental) processes, BS are distinct from APS or frank psychotic symptoms, in which reality testing is already disturbed. These are included in the two psychosis-risk criteria [2, 5, 14, 18]: cognitive disturbances (COGDIS) and cognitiveperceptive BS (COPER) (Online Resource 1)

Aims and hypotheses

Materials and methods

Results

Discussion

Strengths and limitations

Compliance with ethical standards