Maternal well-being and child behavior in families with fragile X syndrome

Abstract

The purpose of this study was to examine the bidirectional relationships relationship between maternal mental health status, maternal stress, family environment and behavioral functioning of children with fragile X syndrome (FXS), the leading cause of inherited intellectual disability. Children with FXS commonly demonstrate challenging behavior related to anxiety, attention, and aggression, whereas mothers of children with FXS have been identified as susceptible to mental health challenges due to their status as genetic carriers of the FXS premutation, as well as the environmental stressors of raising children with special needs. The longitudinal design of this study builds upon prior work that established a concurrent relationship among these factors in families of children with other intellectual disorders. Findings indicated that maternal mental health status was not significantly related to changes in levels of child challenging behavior, heightened child challenging behavior was related to improvements in maternal depression over time, and heightened levels of child challenging behavior was related to increased feelings of maternal closeness toward the child over time. The unexpected nature of the results regarding maternal depression and closeness provides new and more complex hypotheses about how mothers of special needs children demonstrate adaptation and resilience. The findings have implications for maternal and familial mental health treatment as well as future research.

Introduction

Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability (Hagerman, 2008). The syndrome results from an expansion of a trinucleotide (CGG) sequence in the FMR1 gene on the X chromosome, which leads to a deficit of FMRP, a protein that is essential for normal neural functioning (Bassell & Warren, 2008). In the full mutation case, which produces FXS, the CGG sequence is expanded to more than 200 repetitions compared to the healthy allele range of 15 to 54 repetitions (Brown, 2002). In the premutation case, the expansion is between 55 and 200 repetitions Brown, 2002). The premutation can result in both reduced FMRP levels and elevated levels of FMR1 messenger RNA and possible RNA toxicity (Tassone et al., 2000). Although the premutation does not produce FXS, the premutation is associated with adverse phenotypic consequences, including comorbid conditions, such as the neurodegenerative disorder FXTAS (Cornish et al., 2008). In virtually all cases, FXS is inherited from the mother, who will be a carrier of either the FMR1 premutation or full mutation (Nolin et al., 1996). Thus, FXS is a multigenerational disorder and the functioning of each family member is likely to be affected by, and affect, the functioning of other family members (Seltzer et al., 2009). The aim of the present study was to characterize the dynamic bidirectional relationships that exist among child, mother, and family context over time in families affected by FXS.

Most males with FXS have a moderate intellectual disability, and although females are less impaired on average, up to half also meet criteria for an intellectual disability (Hagerman & Hagerman, 2004). In addition to intellectual impairments, FXS is associated with an elevated rate of challenging behaviors relative to conditions such as Down syndrome, although there is considerable within-syndrome variability in this regard (Kau et al., 2004). Behavioral problems associated with FXS include social anxiety, hyperactivity, hypersensitivity to sensory stimuli, increased aggression, self-injurious behaviors, and attention problems (Kau et al., 2004, Kauffman et al., 2004). In addition, individuals with FXS commonly have impaired social and communicative skills (Abbeduto et al., 2004, Lewis et al., 2006) and other behaviors characteristic of autism (Bailey et al., 2008, McDuffie et al., 2012). In fact, 25–33% of people with FXS meet criteria for a co-morbid diagnosis of autistic disorder, with the remainder displaying at least some autistic-like behaviors (Bailey et al., 2004, Brown et al., 1982, Demark et al., 2003, Lewis et al., 2006, Rogers et al., 2001). For males with FXS, a co-morbid autism diagnosis or more severe autism symptoms are associated with more problem and aberrant behavior (especially social avoidance and repetitive behavior), lower levels of adaptive behavior, more severe language impairments, and lower IQ scores relative to boys with FXS alone (Kau et al., 2004, McDuffie et al., 2010, McDuffie et al., 2012).

There is considerable evidence from studies of children with intellectual disabilities of various origins that child challenging behavior is a powerful predictor of maternal stress and poor mental health (Abbeduto et al., 2004, Roberts et al., 2009, Wheeler et al., 2010). At the same time, there is evidence that the child's challenging behaviors can be exacerbated by increased maternal stress and mental health problems, such as depression (Jouriles et al., 1989, NICHD, 1999, Orsmond et al., 2003; Osofsky & Thompson, 2000). In the present study, we were interested in the ways in which the challenging behavior of the son or daughter with FXS affects, and is affected by, the mental health of the mother as well as the family climate.

Biological mothers of individuals with FXS are at elevated risk for mental health concerns. In a sample of these mothers who had clinically significant levels of stress according to self-report, 63% also exceeded the clinical threshold on at least one other measure of maladaptive mental health (Bailey et al., 2008). Relative to women in the general population, biological mothers of children with FXS also display higher rates of social phobia, personality disorders (especially schizotypal personality disorder), major depressive disorder, panic disorder, and agoraphobia (Franke et al., 1998, Roberts et al., 2009). Depression and anxiety, however, are the most frequently diagnosed psychiatric disorders for women with the FMR1 premutation (Franke et al., 1996). Rates of depression for women with the premutation have been identified as ranging from 16% to 40% (Bailey et al., 2008, Franke et al., 1996). Lifetime rates of depression have been cited at 56%, which is far higher than the 10–12% of women who experience depression in the general population (Wheeler, Hatton, Reichardt, & Bailey, 2007). The rate of current diagnoses of anxiety disorders in female carriers of the FMR1 premutation has been found to be 17% (Bailey et al., 2008), and mothers of children with FXS have a frequency of anxiety disorders that is three times higher than that of mothers of children with autism and children who are typically developing (Franke et al., 1996).

It has been suggested that biological mothers of individuals with FXS are more susceptible to mental health problems in part because of their own genetic status as carriers of either the FMR1 full mutation or premutation (Roberts et al., 2009). The evidence on this point, however, is equivocal. Thompson, Rogeness, McClure, Clayton, and Johnson (1996) found that mothers of individuals with FXS had a higher rate of depression (78%) than mothers of children with Down syndrome or spina bifida (37%) who, they argued, cope with similar environmental stressors. In fact, the rates of most types of challenging behaviors, including those reflective of externalizing problems, are higher in FXS than in Down syndrome, spina bifida, and many other syndromes (Dykens et al., 2000); thus, the Thompson et al. data are ambiguous as to the cause of maternal differences in mental health. In addition, Roberts et al. (2009) found that the age-of-onset for psychiatric diagnoses in mothers who were FMR1 expansion carriers occurred much earlier than did their child's diagnosis, which led these investigators to suggest that the high prevalence of affective disorders among the mothers could not be attributed solely to the stress of raising a child with a developmental disability. However, Bailey, Raspa, Bishop, and Holiday (2009) found that the developmental problems of children with FXS are manifested and recognized by parents years in advance of the FXS diagnosis, which raises the possibility that child behavior and delays prior to diagnosis might still be contributing to maternal mental health problems. Nevertheless, relatives of mothers of children with FXS also have a higher frequency of affective disorders (20%) compared to the relatives of mothers of children with autism (11.7%) and relatives of mothers from the general population (3.3%; Franke et al., 1996), supporting the claim that being a premutation carrier confers risk for mental health problems in and of itself. It is likely, however, that it is the dual action of a genetic predisposition and the experiences associated with parenting a son or daughter with severe behavioral challenges that leads to less positive maternal mental health outcomes.

Indeed, there have been suggestions that the stress arising from the parenting role contributes to reduced well-being among mothers of individuals with FXS. Roberts et al. (2009) found that the presence of anxiety disorders in mothers with the FMR1 premutation was not predicted by genetic variables, but was instead strongly related to child variables. In particular, mothers of multiple children with FXS who had elevated scores on the Child Behavior Checklist also displayed higher levels of anxiety (Roberts et al., 2009). Similarly, Abbeduto et al. (2004) found that the strongest predictor of maternal depressive symptoms was the extent and severity of the affected child's behavioral symptoms, a finding replicated by Bailey et al. (2008). In another study of families of children with FXS by Wheeler et al. (2010), child autistic behaviors, challenging behavior, and lack of adaptability were found to be highly correlated with parenting stress, which was itself correlated with maternal depression. Wheeler et al. (2007) found that 55% of the mothers of children with FXS in their sample who reported experiencing significant levels of stress attributed this emotional strain to difficult child behavior. In all of these studies, however, only concurrent relations between maternal psychological status and child behavior problems were examined, which makes it impossible to examine a causal relationship between the variables. An exception is Hartley et al. (2012), who found that child challenging behavior could affect subsequent maternal physiological stress, at least for a subset of women carrying the FMR1 premutation; however, these investigators examined these relationships only over a 24-h period, leaving longer-term relationships unexplored. Moreover, mothers have frequently been the reporters on both their own mental health and the challenging behaviors of their children, raising the possibility that the relationships observed reflect wholly or in part a reporter bias. There is, then, a need to clarify the relationship between maternal mental health and child problem behavior over the course of development in families affected by FXS. In the present study, we used a short-term longitudinal design to examine the extent to which child challenging behavior leads to change over time in maternal mental health. Additionally, fathers rather than mothers were asked to report on child challenging behavior so as to minimize the potential effects of a reporter bias.

Maternal mental health can influence, and be influenced by, the behaviors and characteristics of the child. In fact, there is abundant evidence that maternal mental health problems can have detrimental effects on child social, linguistic, behavioral, and scholastic outcomes (NICHD, 1999). Children of chronically depressed mothers have poorer functioning in the domains of school readiness, verbal comprehension, expressive language, cooperation, and behavior (NICHD, 1999). Mothers who are depressed and therefore demonstrate little sensitivity in their parent–child interactions are more likely to have children who exhibit problematic behavior (NICHD, 1999, Wheeler et al., 2010). Poor maternal mental health status lowers the level of maternal engagement (Wheeler et al., 2007), responsivity to the child (Osofsky & Thompson, 2000), sensitivity within the parent–child relationship (NICHD, 1999), and the occurrence of positive parent–child interactions (Jouriles et al., 1989). Such negative effects appear to be mediated by the nature of the maternal behaviors directed toward the child.

In contrast, developmental outcomes for children with disabilities are improved when parents establish a caring, supportive, and positive family environment (Mink & Nihira, 1986). Children with disabilities who experience cohesion, harmony, and an expressive and child-oriented family environment have been found to have higher levels of adaptive behavior, fewer behavior problems, and experience less peer isolation (Mink, Nihira, & Meyers, 1983). Highly responsive parenting also is related to more positive language outcomes for children with developmental disabilities, including those with FXS (Warren, Brady, Sterling, Fleming, & Marquis, 2010). Conversely, there is evidence from studies of families of adults with intellectual disabilities of varying etiology that declines in maternal psychological well-being can exacerbate child challenging behavior over time (Orsmond et al., 2003). In the present study, we evaluated the extent to which this relationship between changes in maternal mental health and child behavior is also characteristic of families affected by FXS.

Maternal perceptions of the family and relationships within the family may also be impacted by FXS. For example, compared to mothers of adolescents with other developmental disabilities (e.g. Down syndrome), mothers of adolescents and young adults with FXS are more pessimistic about their child's future (Abbeduto et al., 2004, Lewis et al., 2006). High levels of parental pessimism can be problematic because they can contribute to parental stress and serve as a barrier to positive child outcomes. Also, parents who are pessimistic about their child's future level of functioning may be less likely to utilize available services, possibly because they are not hopeful that such services will benefit their child (Floyd & Gallagher, 1997).

Closeness within the mother–child relationship is another domain within the family environment that can be impacted in families of individuals with FXS. Mothers of adolescents and young adults with FXS perceive less reciprocated closeness with their children than do mothers of adolescents with Down syndrome (Abbeduto et al., 2004). Some of the social and emotional characteristics (e.g. eye gaze aversion) of children with FXS may contribute to the difference between FXS and other developmental disabilities in terms of maternal perceptions of closeness. In fact, mothers of sons with co-morbid FXS and autism report perceiving that their children feel less close toward them than do mothers of sons who have only FXS (Lewis et al., 2006).

Conflict within the family environment also can be impacted by having a child with FXS. Mothers of sons with FXS (with and without co-morbid autism) have reported higher levels of family conflict than mothers of children with Down syndrome (Lewis et al., 2006). Family conflict may interfere with the warm and positive parental engagement that characterizes cohesiveness within the family, which has been identified as positively influencing children's emotional and behavioral outcomes (Eisenberg et al., 2005). Indeed, higher levels of family cohesion combined with high levels of parent involvement have been found to result in children with various disabilities demonstrating better independent functioning and social awareness (Mink & Nihira, 1986).

The negative impact of the characteristics associated with FXS on the family environment may be due to poor maternal mental health, child challenging behavior, or both. Abbeduto et al. (2004) found that maladaptive child behavior predicted higher levels of maternal pessimism and less closeness in the mother–child relationship. Children's autistic behaviors also have been found to be significantly correlated with negative control behaviors by mothers (Wheeler et al., 2010). In contrast, children with FXS display less task-related frustration if their mothers are more responsive (Wheeler et al., 2010). Although suggestive, the relationships observed in these studies have emerged from concurrently measured variables, leaving the causal direction of this connection unclear.

In summary, it is clear that levels of conflict, cohesion, and pessimism have important potential implications for the entire family system. Studies have established that concurrent relationships exist between these variables and aspects of child challenging behavior and maternal mental health; however, longitudinal studies are needed to disentangle the relationships among these variables. The present study was focused on the short-term longitudinal relationships among the behavioral characteristics of children with FXS, maternal mental health problems, and the family environment.

Family systems theory suggests that the trends identified regarding maternal mental health, child behavior, and family environment for families with FXS are significant because all three aspects of family functioning have the potential to influence one another (von Bertalanffy, 1968). Because familial relationships exist as a system, the experience of one family member affects all members of the family in some way. This framework provides a rationale for examining the bidirectional relationship between maternal mental health status and child behavioral outcomes, as well as for examining the effects of both of these factors on the overall family environment. Such data are critical for identifying the factors that affect the family system most powerfully and that should be targeted by clinical intervention.

It is clear that the elevated rate of mental health problems for mothers of children with FXS can create barriers to well-being for mothers, children, and families. What is still unclear is how factors within the family system, specifically maternal mental health status, challenging child behavior, and the family environment, influence changes in one another over time. The present study was designed to establish directionality among these constructs. Knowledge of how these factors influence one another can aid in identifying families that are at risk and can help direct clinical interventions with mothers, affected children, and the entire family system. Thus, we addressed the following research questions:

• Does maternal mental health status predict change in child challenging behavior?

• Does child challenging behavior predict change in maternal mental health status?

• Do maternal mental health status and child challenging behavior predict change in the family environment, particularly in levels of closeness of parent-child relationship, family cohesion, family conflict, and maternal pessimism regarding the future of the child with FXS?