Age effect on prevalence of ultra-high risk for psychosis symptoms: replication in a clinical sample of an early detection of psychosis service

Higher frequencies of perceptual and lesser clinical significance of non-perceptual attenuated psychotic symptoms (APS) have been reported by 8- to 15-year-old of the general population compared to 16- to 40-year-old. We examined if such an age-effect can also be detected in a clinical never-psychotic sample (N = 133) referred to a specialized service for clinical suspicion of developing psychosis. APS and brief intermittent psychotic symptoms (BIPS) were assessed using items P1-P3 and P5 (non-perceptual), and P4 (perceptual) of the Structured Interview for Psychosis-Risk Syndromes, current axis-I disorders with the Mini-International Neuropsychiatric Interview, and psychosocial functioning with the Social and Occupational Functioning Assessment Scale. In the sample, 64% reported APS (61%) or BIPS (7%); any perceptual APS/BIPS was reported by 43% and any non-perceptual APS/BIPS by 44%. In correspondence to the results in the general population sample, perceptual but not non-perceptual APS/BIPS were significantly more frequent in younger age groups below the age of 16 (8-12 years: odds ratio (OR) = 4.7 (1.1-19.5); 13-15 years: OR = 2.7 (0.9-7.7); 20-24-year-old as reference group). An age-effect of APS/BIPS on the presence of any current axis-I disorder (59%) or functional difficulties (67%) was not detected. However, when onset requirements of APS criteria (onset/worsening in past year) were met, the likelihood of a psychiatric diagnosis increased significantly with advancing age. Overall, the replicated age-effect on perceptual APS/BIPS in this clinical sample highlights the need to examine ways to distinguish clinically relevant perceptual APS/BIPS from perceptual aberrations likely remitting over the course of adolescence.