Schizophrenia in people with intellectual disability: the role of pregnancy and birth complications.
Birth complications are a red flag for schizophrenia in adults with intellectual disability.
01Research in Context
What this study did
The team compared two groups of adults with intellectual disability. One group had schizophrenia. The other did not. They looked back at pregnancy and birth records for both groups. They counted how many mothers had problems like bleeding, high blood pressure, or long labor.
What they found
People with ID who later got schizophrenia had many more birth problems. Their mothers faced more complications during pregnancy and delivery. The difference was large enough to matter in daily practice.
How this fits with other research
Dougherty et al. (1994) showed you can spot schizophrenia in ID using the PIMRA scale. The new study adds a warning sign: check the birth history first.
Weiss et al. (2001) looked at kids with tuberous sclerosis. They found mild birth problems did NOT predict autism. That seems opposite, but the kids had a different genetic condition. Birth events matter less when a strong gene already drives the risk.
Dodds et al. (2011) studied 129,733 Canadian babies. They saw that birth factors played a small role in autism only when genetic risk was low. Together, these papers tell a story: birth complications weigh more for schizophrenia in ID than for autism in other groups.
Why it matters
When you assess an adult with ID and odd behavior, ask about birth history. A tough delivery does not diagnose schizophrenia, but it adds risk. Pair this clue with the PIMRA scale and current symptoms. You get a clearer picture faster and can rule out other causes.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add two questions to your intake form: 'Any pregnancy or birth problems?' and 'Any labor longer than 12 hours?'
02At a glance
03Original abstract
The literature suggests that mental illness is more common in people with intellectual disability than in the general population. Having reviewed the literature, Turner (1989) [Psychological Medicine 19, 301-14] suggested that about 3% of people with intellectual disability also have schizophrenia. As pregnancy and birth complications (PBCs) occur more commonly in people with intellectual disability than in the general population and are also implicated in the aetiology of schizophrenia, it is possible that these conditions share a common aetiology. This study reports on the occurrence of PBCs in those people with intellectual disability who develop schizophrenia. Fifty people with intellectual disability and schizophrenia were matched for age, sex, degree of intellectual disability and presence of epilepsy with a control group who did not suffer from schizophrenia or a schizophreniform psychosis. The obstetric history was obtained and events rated on a scale specifically designed for this study. This PBCs scale consists of six sub-scales covering areas of general maternal health, pregnancy, delivery, medication in labour, total medication score and neonatal score, as well as an overall total score. The study found that people with intellectual disability who develop schizophrenia have significantly higher rates of PBCs than controls. All of the sub-scales on the PBCs scale were significantly higher in people with schizophrenia, with the exception of the medication scales. Only five out of the 50 people with schizophrenia had not had a major obstetric complication, compared to 13 subjects from the control group. A number of abnormalities were specifically higher in people who later developed schizophrenia. These included: abnormally long or short labour; maternal episiotomy; maternal preeclamptic toxaemia; induction of labour; dysmaturity; maternal smoking in pregnancy; and a delay in neonatal crying. The results suggest that PBCs are important in the aetiology of schizophrenia in people with intellectual disability.
Journal of intellectual disability research : JIDR, 1997 · doi:10.1111/j.1365-2788.1997.tb00703.x