شروع اختلالات روانپزشکی مادری بعد از تولد یک کودک با ناتوانی ذهنی: یک مطالعه گروهی بازنگرانه

Mothers of a child with intellectual disability (ID) have more psychiatric disorders after the birth of their child than other mothers. However, it is unclear if this is because they have more psychiatric disorders before the birth or if the increase is related to the burden of caring for the child. We aimed to calculate the rate of new psychiatric disorders in mothers after the birth of their eldest child with ID born between 1983 and 2005 and to compare these with rates in women with a child with no ID or autism spectrum disorder (ASD) born during the same period. By linking data from Western Australian population-based registries, we selected women with no psychiatric history who survived the birth of their live-born child (N = 277,559) and compared rates of psychiatric disorders for women with a child with ID and women without a child with or ASD. Negative binomial regression with STATA 12 was used for all analyses. Mothers of children with mild–moderate ID of unknown cause had around two to three and a half times the rate of psychiatric disorders of mothers of children without ID or ASD. Mothers of children with Down syndrome and no pre-existing psychiatric disorder showed resilience and had no impairments in their mental health. Interventions and services are needed for mothers of other children with ID to improve their mental health. Further research is implicated to explore the mental health of mothers of children with ID and a pre-existing psychiatric disorder.

Intellectual disability is diagnosed in people with an IQ of less than 70 and deficits in adaptive functioning which are present before 18 years (American Psychiatric Association, 2000). Children with intellectual disability have more challenging behaviours (Baker et al., 2002), more sleep disorders (Richdale et al., 2000) and more psychopathologies than typically developing children (Emerson, 2003). Their mothers also have increased expenses (Parish and Cloud, 2006) perceive more stigma against themselves or their child (Green, 2007) have lower employment levels (Shearn and Todd, 2000) and less informal and family support (Shearn and Todd, 2000) than other mothers. Therefore, it is not surprising that research has identified poorer mental health in mothers of children with intellectual disability compared to the parents of children with no disabilities (Bourke et al., 2008, Emerson et al., 2010 and Olsson and Hwang, 2001). In a previous study (Fairthorne et al., submitted for publication), we found that mothers with an outpatient psychiatric history were about twice as likely to have a child with intellectual disability compared to mothers of children with no intellectual disability. We hypothesised that this might be due to shared genetics of the mother and the child with intellectual disability or prenatal use of medication or life-style factors in women with a psychiatric disorder. In the current paper, we wanted to ascertain whether mothers of a child with intellectual disability and no previous psychiatric history were at increased risk of having a psychiatric disorder after the birth of their child. We reasoned that these comparisons would enable us to discern whether the burden of caring for a child with intellectual disability contributed to the increased rate of psychiatric disorders in their mothers. This being so, better informed services and interventions might be instituted with the aim of reducing the burden of these mothers and improving their mental health. No previous research has attempted to differentiate whether the excess of psychiatric disorders in mothers of children with intellectual disability after the birth of their child is due to the increased burden of caring, a prior disposition to psychiatric disorders or to increased exposure to ante-natal risk factors for intellectual disability in women with a previous psychiatric disorder. Moreover, grouping mothers, according to the level of intellectual disability of their child and according to whether the cause is known would enable the most vulnerable groups of mothers to be identified. Therefore, according to type and level of intellectual disability, we aimed to: 1. Compare the incidence of any psychiatric diagnosis in mothers after the birth of a child with intellectual disability compared to mothers with no child with intellectual disability or autism spectrum disorder (ASD) where mothers had no record of a psychiatric disorder before the birth of their child. 2. Compare the incidence of the most frequent psychiatric diagnostic categories, in mothers after the birth of a child with intellectual disability compared to mothers with no child with intellectual disability or ASD and where mothers had no record of a psychiatric disorder before the birth of their child.

In this study, we excluded mothers who had a hospitalisation or an outpatient contact for a psychiatric disorder in WA before the index birth. We made adjustments for maternal age, parity, socio-economic status and year band of the index birth, all of which might have been related to the odds of a subsequent psychiatric disorder. Therefore, it is reasonable to conclude that the elevated (and attenuated) incidence of psychiatric disorders we identified is mostly due to the burden of caring rather than genetics or pre-existing environmental factors. Hence, we concluded that the burden of caring for a child with intellectual disability of known cause excluding Down syndrome and particularly of mild–moderate intellectual disability without a known cause increases the risk of a psychiatric disorder after the birth of their child. We did not find this association for mothers of children with Down syndrome. Exploring the IRRs of psychiatric disorders in these same subgroups of intellectual disability but in mothers with previous psychiatric disorders might provide evidence of groups of mothers who are particularly vulnerable after the birth of their child with intellectual disability.