<b><i>Background:</i></b> Psychiatric disorders are often linked to dysfunctions within neurotransmitter systems, and the same systems play a role in healthy temperaments. Development of a common bio-behavioural taxonomy based on functionality of neurotransmitter systems suggests examining temperament profiles in patients with various psychiatric disorders. <b><i>Objective:</i></b> (1) To investigate temperament profiles in two age groups of children with delusional disorders; (2) to investigate temperament profiles in adolescents with mood disorders; (3) to investigate temperament profiles in in vitro fertilisation (IVF) children. <b><i>Methods:</i></b> Sample: in total 171 participants (M/F = 91/80), healthy children and teenagers (volunteers); two age groups of children with psychotic disorders; teens with mood disorders (clients of the Federal Mental Health Center) and healthy IVF. Parents of participants completed a test based on the neurochemical model Functional Ensemble of Temperament (FET). <b><i>Results and Conclusions:</i></b> (1) Both age groups of children with psychotic disorders had significantly lower scores on the scales of physical endurance, tempo, plasticity, and self-satisfaction, in comparison to healthy controls; the psychotic group aged 5–11 had also lower scores on the impulsivity scale, whereas the psychotic group 12–17 had lower scores on the social endurance and social tempo scales and higher neuroticism. (2) Teens with mood disorders had lower scores on the self-confidence-satisfaction scale and higher scores on the impulsivity scale, in comparison to controls. (3) No difference between IVF and naturally conceived children were found. The results show the benefits of using the FET framework for structuring the correspondence between psychiatric disorders and temperament as it differentiates between social versus physical aspects of behaviour and orientational versus executive aspects.