Growth in young adults who screen positive for non-affective psychosis: birth cohort study

While birth cohort studies have shown that individuals who develop non-affective psychosis show subtle deviations in cognitive and behavioural developmental trajectories, there is less evidence about deviations in physical growth in these individuals. The purpose of the present study was to examine the association between behaviour and growth and maturation from infancy, through childhood and adolescence to early adulthood and the development of non-affective psychosis in young adults.

Based on a birth cohort of 3801 young adults, weight and length/height were examined at birth and at years 5, 14 and 21, together with pubertal maturation at year 14. Behavioural measures taken at years 5 and 14 were also examined. Screen-positive non-affective psychosis (SP-NAP) was assessed at year 21 using Composite International Diagnostic Interview, or a self-report checklist. The association between the behavioural and growth measures at birth and at years 5, 14 and 21, and SP-NAP at year 21 was examined using logistic regression.

There were 60 subjects in the cohort who were classified as having SP-NAP. In female subjects SP-NAP was significantly associated with being longer with a larger head circumference at birth, and less likely to be associated with being shorter at 21 years, with consistent trend associations for height between. There were no differences for weight. There was no significant association between the variables of interest in male subjects or for the total group. There was also no significant association between pubertal development at age 14 and risk of SP-NAP in either sex.

Unlike developmental behavioural problems, which showed continuity from childhood through adolescence, SP-NAP was not associated with marked deviations in growth trajectory for male subjects, but the present data suggests that female subjects with SP-NAP had an altered skeletal growth trajectory.