Psychosis risk individuals show poor fitness and discrepancies with objective and subjective measures

Abstract

Exercise is a promising intervention for individuals at clinical high-risk for psychosis (CHR). However, these youth may not be reliable reporters on fitness. There have been no investigations that utilized objective fitness assessment in this population. The present study objectively characterizes the level of fitness in CHR youth, compares the accuracy of self-report measures to objective fitness indices, and explores clinical factors that may influence the accuracy of self-reported measures of fitness. Forty CHR individuals completed an exercise survey and objective indices of fitness (i.e., VO₂max and BMI). Forty healthy volunteers completed objective indices of fitness and a structured clinical interview ruling out the presence of psychiatric illness. CHR youth showed greater BMI and lowered VO₂max compared to healthy volunteers. In the CHR group, self-report items (perceived fitness) did not reflect objective indices of fitness, whereas specific exercise behaviors (intensity of exercise) showed stronger correlations with objective fitness measurements. Exploratory analyses suggested that symptoms (grandiosity and avolition) related to errors in self-perception. Results indicate that CHR individuals are less fit than controls as indexed by objective measures of fitness and that it is important to consider unique population clinical characteristics when employing self-report data.

Figure 1

CHR physical markers of fitness and perceived fitness metrics: CHR group differences in VO₂ max (A) and body mass index (B).

Figure 2

Relationship of objective physiological health to self-reported measures of fitness: (A) Within the CHR group relationships between VO₂ max to reported exercise intensity, (B) BMI to reported exercise intensity, (C) BMI to reported time spent exercising, (D) intercorrelation matrix of the perceived and actual fitness metrics.

Figure 3

Errors in perception related quartiles groups (inaccurate and accurate) for BMI (top panels) and VO₂max (bottom panels) to symptoms of (A,C) grandiosity and (B,D) Avolition.