Affective symptom dimensions in early-onset psychosis over time: a principal component factor analysis of the Young Mania Rating Scale and the Hamilton Depression Rating Scale.

Early-onset psychosis (EOP) is a complex disorder characterized by a wide range of symptoms, including affective symptoms. Our aim was to (1) examine the dimensional structure of affective symptoms in EOP, (2) evaluate the predominance of the clinical dimensions and (3) assess the progression of the clinical dimensions over a 2-year period. STROBE-compliant prospective principal component factor analysis of Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale-21 (HDRS-21) at baseline, 6-months, 1-year and 2-year follow-up. We included 108 EOP individuals (mean age = 15.5 ± 1.8 years, 68.5% male). The factor analysis produced a four-factor model including the following dimensions: mania, depression/anxiety, sleep and psychosis. It explained 47.4% of the total variance at baseline, 60.6% of the total variance at 6-months follow-up, 54.5% of the total variance at 1-year follow-up and 49.5% of the total variance at 2-year follow-up. According to the variance explained, the mania factor was predominant at baseline (17.4%), 6-month follow-up (23.5%) and 2-year follow-up (26.1%), while the depression/anxiety factor was predominant at 1-year follow-up (23.1%). The mania factor was the most stable; 58.3% items that appeared in this factor (with a load > 0.4) at any time point appeared in the same factor at ≥ 3/4 time points. Affective symptoms are frequent and persistent in EOP. Mania seems to be the most predominant and stable affective dimension. However, depression and anxiety may gain predominance with time. A comprehensive evaluation of the dimensional structure and the progression of affective symptoms may offer clinical and therapeutic advantages.