Schizophrenia clinical features

Clinical phases of schizophrenia

Premorbid social and developmental impairments

Child and adolescent onset schizophrenia is characterized by poor premorbid functioning and early developmental delays (Alaghband-Rad et al. 1995; Hollis 1995). Similar developmental and social impairments in childhood have been reported in adult onset schizophrenia using population-based cohorts free from referral biases (Done et al. 1994; Jones et al. 1994; Jones & Done 1997; Malmberg et al. 1998). While age of onset comparisons are plagued by methodological difficulties, premorbid developmental impairments appear to be more common and severe in the child and adolescent onset forms of the disorder.

Hollis (1995) in a retrospective case - control chart study of 61 cases of child and adolescent onset schizophrenia (aged 7 - 17) reported significant impairments in language development (23%), motor development (31%) and social development (36%). Developmental impairments were most common in cases with onset of schizophrenia before age 13 years. Hence, a history of premorbid impairments appears to be most common in the very earliest onset cases. Nicholson et al. (2000) reported significant premorbid speech/language, motor and social impairments in 50% of childhood onset patients with onset of psychosis before the age of 12 years. In comparison, language and motor developmental delays are reported in only about 10% of individuals destined to develop schizophrenia in adult life (Jones et al. 1994).

A consistent characteristic in the premorbid phenotype is impaired sociability. In child and adolescent onset schizophrenia, about one-third of cases have significant difficulties in social development affecting the ability to make and keep friends (Hollis 1995). Similar, but less frequent difficulties with premorbid sociability have been noted in representative population samples of adult schizophrenia (Malmberg et al. 1998). Interestingly, the Hollis study (1995) indicated that some cases would have met diagnostic criteria for Asperger syndrome, schizotypal personality disorder or atypical autism prior to the onset of psychosis

In the National Institute of Mental Health (NIMH) study of childhood onset schizophrenia, 34% of cases demonstrated transient symptoms of pervasive developmental disorder during the premorbid period (Alaghband-Rad et al. 1995).

Premorbid IQ appears to be lower in child and adolescent onset schizophrenia than in the adult form of the disorder. The mean premorbid IQ lies in the mid to low 80s, 10 - 15 IQ points lower than in most adult studies (R. Asarnow et al. 1994; Spencer & Campbell 1994; Alaghband-Rad et al. 1995). In the Maudsley study (Hollis 1999) one-third of child and adolescent onset cases had an IQ below 70 (mild learning disability range).

One interpretation of these findings is that a subgroup of adolescent schizophrenic cases has abnormal premorbid development with the rest developing normally. In fact, careful analysis shows that there is no abnormal developmental subgroup - this is simply an artefact of using rather crude categorical measures of premorbid development. Continuous IQ measures show that the whole distribution of IQ is shifted down compared with both adolescent affective psychoses and adult schizophrenia.