The impact of affective and negative symptoms on the development of psychosis in a six-year follow-up of a community-based population

The Clinical High Risk (CHR) concept has a limited transition risk to psychotic disorders (PD). This study investigates the association between affective and negative symptoms, currently not included in the CHR concept, and the risk of transition to PD in a community-based population of 2185 participants in Turkey.

Participants were assessed twice over six years using a multistage sampling technique. Two separate linear regression analyses were conducted on data from both assessments, investigating the relationship between affective and negative symptoms, subclinical and clinical psychotic experiences (PE) and progression to PD.

The overall transition rate to PD was 1.3%. The analysis showed no increased risk of developing PD for the 'subclinical PE only' group at follow-up, compared to the 'no PE' group. However, being classified as having 'clinical PE only' (OR: 6.23; p = 0.010) and 'clinical PE + affective/negative symptoms' (OR: 8.48; p = 0.001) at baseline was associated with an increased risk of developing PD at follow-up. The presence of 'affective/negative symptoms' at baseline was associated with an increased risk of incident subclinical PE (RR: 1.98; p = 0.001), incident clinical PE (RR: 3.14; p = 0.001), and incident PD (RR: 4.21; p = 0.030) at follow-up.

The results confirm the significance of the baseline severity of positive symptoms in predicting the transition to PD and suggest that both positive and affective/negative symptoms impact the transition risk to PD and incident psychotic symptoms. This highlights the potential utility of defining CHR groups based on a combination of positive, affective, and negative symptoms.