Adverse childhood experiences (ACEs) are potentially traumatic events experienced by individuals when they are younger than 18 years old and include emotional, physical, and sexual abuse as well as neglect and household dysfunction (Felitti et al., 1998). In a systematic review of international studies among general adult population samples (Madigan et al., 2023) and in a national survey of general adult populations in the United States (Swedo et al., 2023), more than 60 % reported at least one ACE, and 16–17 % reported four or more ACEs. Sexual abuse is less commonly reported than other types of abuse or neglect but has been estimated to have been experienced by as many as 24 % of children worldwide (Massullo et al., 2023).

ACEs are associated with significant mental and physical health problems not only in childhood but throughout adulthood (Felitti et al., 1998; Guo et al., 2023; Li et al., 2023; Madigan et al., 2023). Persons with a mental health condition are particularly likely to report having experienced four or more ACEs (Madigan et al., 2023), as childhood adversity increases vulnerability to multiple psychiatric disorders including psychosis (Varese et al., 2012; Kessler et al., 2010). If individuals with a high number of ACEs receive a diagnosis of depression, their symptoms tend to be more severe (Humphreys et al., 2020). Furthermore, among adults diagnosed with depression, the estimated prevalence of emotional, physical, and sexual abuse is 36.7 %, 27,6 %, and 25.3 %, respectively (Nelson et al., 2017). In a review of 27 studies on ACEs among older adults, depressive symptoms were the most frequently identified correlates of ACEs and were a moderator of the relationship between ACEs and cognitive impairment (Haczkewicz et al., 2024). In a population of depressed older adults (aged 60–93 years), more than half (53.3 %) of all participants reported experiencing childhood abuse (Comijs et al., 2013). While several ACEs have been found to be associated with depressive symptoms among older adults, physical, sexual, and emotional abuse were the ACEs most consistently shown to be related to a wide range of adverse outcomes in late life samples (Haczkewicz et al., 2024), suggesting that childhood abuse may be a risk factor for those with late-life depression. This is consistent with evidence from a recent study of a representative population sample of youth and young adults that found that sexual, physical, and emotional abuse had a stronger relationship with negative trajectories of mental health over a five-year period than any other ACE except for family history of suicide attempts (Li et al., 2023).

Both childhood maltreatment (Miu et al., 2022) and depression (Joormann and Gotlib, 2010; Reichler et al., 2025) are associated with problems of emotion regulation. For example, all types of childhood maltreatment (except for sexual abuse) have been linked to higher levels of trait anger and anger attacks in adulthood (de Bles et al., 2023), and studies have shown that anger problems are associated with both childhood abuse and major depression (Dvir et al., 2014; Zhou and Zhen, 2022). Emotion dysregulation has been identified as a potential mediator of the relationship between childhood maltreatment and adult depression (Klumparendt et al., 2019). However, the neurobiological underpinnings and maladaptive thought processes that may mediate the relationship between childhood abuse and subsequent anger issues is not well understood.

Many neuroimaging studies have demonstrated that childhood abuse is associated with alterations in resting-state functional connectivity (rs-FC) across multiple brain regions and networks (van der Werff et al., 2013; Banihashemi et al., 2022; Fadel et al., 2021; Korgaonkar et al., 2023; Goltermann et al., 2023). One systematic review examining children and adolescents who have experienced childhood maltreatment (abuse and neglect) showed decreased connectivity within the salience network and increased connectivity between the amygdala and prefrontal, default mode, and salience networks (Gerin et al., 2023). One study examining depressed middle-aged adults reporting childhood maltreatment found rs-FC changes in sensory and cerebellar networks (Gálber et al., 2024). Lastly, in a large study examining older adults aged (45–79 years), individuals with higher childhood maltreatment scores exhibited decreased rs-FC in the prefrontal cortex, temporal cortex, precuneus, fusiform gyrus, and medial orbitofrontal cortex (Wan et al., 2022). This reduction in FC mediated the relationship between childhood maltreatment severity and adverse mental health outcomes such as addiction, anxiety, depression, and decreased cognitive performance (Wan et al., 2022). These findings highlight that childhood trauma can affect many brain regions and networks, but most prior research has focused on children, adolescents, and young or middle-aged adults.

In addition, the findings primarily show evidence of deficient adaptive connectivity within and across networks that play key roles in emotion, behavioral, and cognitive regulation, consistent with the “harmful theory” of chronic stress and allostatic load (Lupien et al., 2009; “National”, 2005; Shonkoff et al., 2012). However, other affective and behavioral neuroscience researchers have proposed an alternative adaptive theory of maltreatment (Teicher et al., 2003; Teicher and Samson, 2016). In adapting to survive maltreatment, the child's brain may manifest an increased functional connectivity in diverse neural networks, including 1) the emotional or sensory-processing networks due to reduced threshold to chronic stress (McEwen and Gianaros, 2011; Teicher et al., 2016) or overt response to certain types of abuse, 2) networks that typically are not synchronized to compensate weakened executive control function, attention, or emotion regulation, and 3) default mode-network to internalize trauma or stress. Given the diverse adaptive responses that occur across neural systems, it is not surprising that a wide array of brain regions may show evidence of adaptive alteration rather than only, or primarily, maladaptive harm in individuals with a history of childhood abuse, including limbic, prefrontal, sensory, and midline cortical structures. Therefore, in the present study, a range of neural networks will be probed for diminished or heightened interconnectivity.

There are several neuroimaging studies on rs-fMRI patterns in late-life depression (LLD). Some found low resting FC within the cognitive control network (CCN) and high resting FC within the default network (DMN; Alexopoulos et al., 2012). Others found greater connectivity in the posterior nodes of the DMN, and lower connectivity in the anterior nodes of the DMN (Andreescu et al., 2013). In another study, those with LLD exhibited increased connectivity in the default mode, visual, and auditory networks compared to controls (Eyre et al., 2016). Meta-analysis did not find any consistent findings across reports in the literature, which supports high etiological heterogeneity in LLD (Saberi et al., 2022). Childhood abuse-associated network changes should be part of the heterogeneity. However, little is known about the association between childhood abuse and neural network changes among adults with LLD. Investigating the impact of abuse on the brain in LLD patients is crucial to understanding how maladaptive thought processes and emotional dysregulation arise within this population.

Although there are documented relationships between childhood abuse and depression and chronic anger and depression, the relationship between childhood abuse and chronic anger in the context of LLD has not been systematically investigated. Recent research also suggests that distinct patterns of functional connectivity in the limbic and temporal regions and the parietal and prefrontal regions of the brain may underlie the association between emotion dysregulation and depression in different contexts of childhood adverse experiences (Gao et al., 2025). Therefore, the role of neural mechanisms warrants inclusion when investigating the relationship between childhood abuse and chronic anger in the context of late life depression.

Rumination, defined as the repetitive focus on self-distress and its causes, is a key maladaptive thought process that may connect early childhood abuse to later problems with emotional regulation. Kim et al. (2017) showed that rumination (particularly the brooding subtype) mediates the relationship between childhood trauma and depressive or anxious symptoms, indicating that rumination may play a role in contributing to trauma-induced mood symptoms. Thus, rumination offers a plausible pathway linking childhood abuse to chronic anger in LLD.

To address these gaps in the evidence base, the current study investigated whether adults with LLD and a history of childhood abuse (emotional, physical, and/or sexual) exhibit altered rs-FC, and whether those neural mechanisms mediate the relationship between childhood abuse and chronic problems with anger. We hypothesized that adults with LLD who report childhood abuse, compared with those who do not report childhood abuse, would show: (1) altered rs-FC in the fronto-striato-cerebellar circuits responsible for emotional regulation and cognitive control and (2) higher levels of chronic anger. In exploratory analyses, we also tested whether rumination contributed to this pathway.