An exploration of addiction in adults experiencing early-life stress: a metasynthesis 1

ABSTRACT Objective: to review and synthesize qualitative research on the links between early-life stress and addiction behaviours in adulthood. Method: metasynthesis to review qualitative research findings based on procedures that outline how to identify themes or constructs across studies in a specific area. Comprehensive searches of multiple electronic databases were performed. The initial search yielded 1050 articles and the titles and abstracts were screened for inclusion based on predetermined criteria. Thirty-eight full text, peer-reviewed articles were retrieved and assessed by three independent reviewers. Twelve articles were eligible for full review and appraised using the Critical Appraisal Skills Programme (CASP) tools. Results: the findings revealed that clear associations exist between early-life stress and addictive behaviours in adulthood, such as between trauma in childhood, violence, and addictive behaviours. A common theme in the findings indicates that participants turn to addictive substances as a way of strategically coping with stressful childhood experiences, regardless of the harmful side effects or detrimental social outcomes. Conclusion: it can be inferred that addiction may be viewed as a way to deal with adversity in childhood and that there is an interrelationship between addiction, domestic violence and crime.


Introduction
Healthy child development is built on a foundation of supportive and responsive relationships with caregivers (1) . The stress associated with the disruption or absence of these relationships when brain structures are developing, has long-term and negative effects on emotional, behavioural, social, and physical health and well-being throughout an individual's life (2)(3) .
Child maltreatment is an umbrella term for all forms of physical/emotional/sexual abuse, neglect, and exploitation that occurs before 18 years of age and is associated with actual or potential harm to the child's health, survival, development, or dignity (4) .
The following four categories of child maltreatment are typically recognized: neglect, physical abuse, psychological or emotional abuse, and sexual abuse (2,(5)(6)(7) . Child maltreatment is a serious public health problem around the globe (8) and has implications for childhood mortality and morbidity and lifelong mental health, substance misuse, high-risk sexual behaviour, obesity, and criminal behaviour (9)(10) .
Rates of child maltreatment are challenging to estimate because of differences in definitions, sampling strategy, and method of data collection, as well as methodology. What is more disconcerting is that 50% -80% of cases go unreported (8,10) . A meta-analysis of 13 independent samples (n=59,406) reported that 16.3% of children around the world are victims of physical neglect and a further 18.4% have experienced emotional neglect (11) . As many as 25% of adults report having been physically abused as children (4) . Another meta-analysis (12) (331 independent samples and n=9,911,748 participants) estimated the international prevalence of child sexual abuse to be 12.7%. The same study found that rates of sexual abuse of females and males to be 18% and 7.6% respectively.
Studies suggest that the early-life associated with child maltreatment also has deleterious consequences in adulthood (13) . Adults who have experienced some form of early-life stress may present with a wide range of physical health problems, mood, anxiety, and personality disorders, and/or misuse of alcohol and other licit and illicit substances (6,(14)(15) . The effects of child maltreatment serve as markers of endophenotypic susceptibility to diseases through the hypothalamicpituitary-adrenal (HPA) axis dysfunction (16) . Early-life stress can result in permanent changes in HPA axis function, morphological changes in the brain, and gene expression changes, all of which are implicated in the abuse of psychoactive substances (17) . In

Aim
The purpose of this metasynthesis was to explore studies on early-life stress and links to addiction in adulthood. The specific procedural steps were to search, appraise, classify, and synthesize the findings of qualitative research in order to describe the existence of addiction among adults with links to the experience of early-life stress.

Method Design
Metasynthesis is an approach to reviewing qualitative research findings based on procedures that outline how to identify themes or constructs across studies in a specific area. This metasynthesis involved a comprehensive search, appraisal of the results of qualitative studies, study classification, and synthesis of the results (18) . These procedures were chosen because it allows the researcher to build a set of relevant assumptions, aggregating the results of several primary studies; and to discover the "state of the art" whereby the contributions of Teixeira CAB, Lasiuk G, Barton S, Fernandes MNF, Gherardi-Donato ECS.
combining qualitative research findings enhances their contribution to the development of new knowledge and future knowledge applications (19)(20)(21)(22) . The goal of a metasynthesis is to broaden and deepen the understanding of a particular phenomenon (23) .

Search method
Comprehensive searches of Medline, PsycINFO, CINAHL, Web of Science and SCOPUS databases were performed. Primary search terms included subject headings and text words associated with key concepts related to the review question. The terms were divided into three broad categories: 1) child abuse ("trauma" "Battered Child Syndrome", "adverse experience", "aggression", "forced sex", "child abuse", "victim", early life experience"); 2) addiction/ misuse of substances ("substance-related disorders", "addiction", "substance misuse", "overconsumption"); and 3) qualitative studies ("qualitative research", "anthropology", "ethnography", "hermeneutic", "phenomenology", "lived experience", "grounded The peer-reviewed articles were retrieved and assessed by three independent reviewers. In case of disagreement in any of the phases, the articles were re-read and discussed until the disagreement was resolved. EndNote ® was used to organize and manage references. Inclusion/exclusion criteria were developed using a modified PICOS framework (24) :  (25) . The Checklist consists of 10 questions: two for the selection of studies and eight for the design of research, data collection and analysis, ethics, reflexivity and implications of qualitative research (26) . According to the authors, the first three questions are fundamental. If for any of them the answer is "no," the article has to be excluded; thus the article is considered outside the required methodological standards criteria and is left out.

Data Extraction
The instrument elected to extract the data was adapted (27) and has been used in earlier studies (28)(29) .
The adapted items used were author, title, keywords, journal, database, country, year, aim, methods, findings, reference and additional information. The reviewers independently reviewed the extracted data using this instrument, which consists of five domains: identification of the study, setting of study, journal, methodological characteristics of the study, and quality appraisal.

Data analysis
Employing a method (30) that the data were analyzed in the following way: (i) initial reduction/ classification of the data into systematic categories; (ii) clustering of primary source data through an interactive contrasting, comparing process; and (iii) drawing conclusions about each sub-group analysis and synthesizing relevant elements into an integrated summary (31) .

Validity
The validity for this meta-synthesis was grounded in a comprehensive search for literature, group discussion on search terms and inclusion criteria (18) , group assessment of appraisal of CASP, and agreement about decisions. The authors also discussed findings of the studies and themes until a consensus was reached.

Results
The initial search generated 1050 records; 22 duplicates were removed. Preliminary screening of titles resulted in the elimination of an additional 929 records. The abstracts of the remaining 126 records were screened and 88 of these were discarded. The full texts of 38 records were reviewed and the 12 articles that met all inclusion criteria were retained for full review (See Figures 1 and 2).

Bittar & Nakano (2011) Brazil
Generic qualitative approach 10 women, mothers living in the context of alcohol, drugs and violence.
The family and social context in which the women lived during their process of socialization in their original family home unites factors that contribute to manifest acts of violence against their children.
Aggressive mothers have a common profile like aggression and loss in childhood, alcohol abuse situations in adulthood.

Bittar, et al. (2012) Brazil
Generic qualitative approach 10 women, mothers living in the context of alcohol, drugs and violence.
The abuse victims are more prone to learning disabilities, behaviour disorders, self-defeating behaviours and low self-esteem.

Bowles, DeHart & Webb (2012) USA
Grounded Theory 60 women incarcerated in a maximum security facility.
Substance use may arise from a need to cope with child victimization and adversity, and those factors such as poor parental supervision may contribute to substance use. After onset of drug use, many women may turn to further criminal activity to support their habits. (the Figure 2 continue in the next page...) Teixeira CAB, Lasiuk G, Barton S, Fernandes MNF, Gherardi-Donato ECS. Such physical punishment also socialized and prepared children for the violence that would likely occur during their childhood. This analysis highlights how reducing substance abuse in the inner city may require a much more comprehensive effort than a focus on reducing physical abuse in childhood.
Hänninen & Koski-Jännes, (1999) Finland Narrative psychology 51 (22 men and 23 women) people who had been able to quit their addiction to alcohol, multiple drugs, binge eating, smoking, sex and gambling.
As there are several ways out of addictive behaviours there are also several ways to construe the change. People who try to quit addictive behaviours could be encouraged to make full use of the cultural stock of stories in creating an account that fits their own experience of defeating their particular addiction.

Johnson & Young (2002) USA
Relational theory 5 women with drug history and had 3 or more incarcerations.
The effects of childhood sexual abuse continue to impact women into adulthood. Alcohol and drugs were also used as a way to endure the trauma associated with early sexual abuse.

Mirlashari, et al. (2012) Iran
Grounded theory 15 drug users and 4 family members (men and women) who were recruited from treatment centers.
There appears to be a significant disconnect between individuals who experienced traumatic events during childhood and their families. An obedience instilling parenting style and parents' knowledge and attitude toward drug using and prevention were also identified as important determinants of substance use. Nearly half of the Trinidad group and two-thirds of the Barbados group reported experience of rejection or abandonment in childhood. A profile of stressful or traumatic experiences was compiled for each participant, from which it was possible to identify co-occurring pairs of stressors, which suggest interrelationships between the phenomena. Others reported stress related to parental loss, divorce, and abandonment. In all studies, early life stress was self-reported. There was no use of instruments to measure child abuse.
The findings of this metasynthesis support the claim that for many people, adult addiction is closely related to early-life stress. The major theme across all 12 studies in this review is that use of psychoactive substances, gambling, and sex served as ways of coping with stressful circumstances experienced at an early age. In some studies (32)(33)(34)(35)(36) participants report engaging in addictive behaviours in childhood which continued into adulthood. Regardless of when the addiction behaviour began, the common factor among participants is that addiction in adulthood is a way of coping with the effects of early-life stress.
The others highlighted adverse situations experienced in childhood as an important factor in the misuse of chemical substances.

Addiction as a Coping Strategy
Coping, defined as a set of cognitive-behavioural actions developed by the individual throughout their life course experiences, develops as a result of many stressors, in order to change adverse aspects in the environment and regulate potential threats arising from these (44) . Coping strategies are used to deal with demands or stressors (internal or external) that a person judges as being above their resources (44) . It is understood, therefore, that the means an individual uses to cope may change over time, according to the features of the stressor and contextual factors (45) . factors. These contribute to a worldview and shape the meaning, value, and significance ascribed to a particular situation or event and helps to explain why two individuals may perceive and react differently to the same circumstances (48) .
The coping processes constitute a mobilization of cognitive and behavioral efforts to manage (reduce or tolerate) the internal or external demands that arise from the interaction with the environment (48) . These coping efforts may be either problem-focused or emotion-focused. The way a person perceives a stressful situation (i.e., cognitive appraisal) influences how they will attempt to cope (49)(50) .
Problem-focused coping focuses on changing the environment to eliminate or modify the stressful situation. In other words, the person seeks to understand the stressor and tries to modify it. Emotionfocused coping is aimed at alleviating the emotional distress experienced by the person. That is, the person tries to mitigate the suffering related to the stimulus (51) .
Emotion-focused coping can be considered a way of avoiding direct confrontation with the stressor and referred to as avoidant coping.
Studies included in this review focused on childhood experiences, which would be considered as traumatic.
This finding is aligned with the results of other studies, including a study (52) with families and children about the use of substances that connect physical, emotional and sexual abuse to a sense of degradation, humiliation and drug use. Also, individuals who suffered multiple maltreatments had low self-esteem and were involved in more risk behaviours, including increased use of alcohol and other drugs (53) .
In an attempt to avoid the negative feelings, participants used the addiction behaviours as a way of trying to escape painful memories or limit stressful situations, what is referred to as avoidant coping. There's a relationship between early life stress, educational level, and the use of avoidant coping in the misuse of substances and mental disorders in women (54) . and respect. In fact, these children accepted that being abused was a part of being a child. In justifying their punishments, they came to define parental assault as culturally normative as revealed in some of the reviewed articles (37)(38)41,43,55) .

Often, there is no self-reflection about this behaviour,
which leads to a repetition of the dysfunctional pattern of abuse and addiction within the family environment. As the person has no knowledge of how to cope otherwise with the traumatic events he/she is experiencing, they continue to adopt and repeat the same behaviours learned within the family environment.
It was recognized that some participants were using the same learned behaviour as a method of discipline that their parents had used. Unfortunately, it is noted that their development and ability to process family interactions are likely to be impaired with predictable outcomes; and that such situations have potential for perpetuating the patterns of vulnerability and risk for these adults. This creates a vicious cycle of abuse and addictive behaviour.

Forgetting Pain Caused by Traumatic Memories
The addiction behaviours are an understandable attempt to decrease the emotional and mental pain caused by such traumatic and violent experiences. The individuals disclosed experiences of abuse, incest, rape and many other horrors that lead to drug and alcohol use, in order to extinguish pain as revealed in many of the reviewed (32)(33)(34)(35)(36)(39)(40)55) .
The participants in the reviewed studies used an array of different drugs to find balance in a life of pain.
A lack of self-esteem, the tendency toward depression, and the feelings of shame and inadequacy set the stage for addiction behaviour. Indeed, it was a form of selfmedication, because with these substances can come some temporary relief to the pain of recalling severe and traumatic memories.

Addiction, Violence, and Crime
One of the major findings from the present study is that violence was commonplace in the household.
Prior examination of literature reveals that household violence is part of a complex of sub-cultural norms that can involve drug use and sexual exploitation. Such a scenario can be seen in other qualitative studies, revealing the problem of violence in the context of misuse of substances (55)(56) .

Limitations
One of the limitations of this study is the lack of access to transcripts of the included material. Due to it being a metasynthesis, access to the transcripts of the participants could bring greater depth to the discussion, which limits the interpretation of synthesized information.
In spite of these limitations, the metasynthesis revealed some promising results that can inform and guide effective health promotion and disease prevention actions in nursing practice.

Conclusions
The