Adverse childhood experiences (ACEs) have been attributed to harmful health behaviors and the risk of chronic diseases in adulthood. This research investigated the relationship between ACEs and substance use disorders in patients with schizophrenia. In the current study, only 14.4% of the studied patients had zero ACE. This means that 85.6% of the studied patients had at least one ACE. Almost one-quarter of the studied patients had ≥ 4 ACEs.
In line with our study, Schalinski et al. (2017) found that 80.5% of patients with schizophrenia had at least one type of childhood trauma, and 48.9% had more than two types of traumas. In addition, 18.3% and 13.3% had one and two types of traumas, respectively, while 19.4% of Schizophrenia patients had no ACE [22].
On the other hand, Andrianarisoa et al. (2017) reported a high prevalence of childhood trauma (82.5%) among schizophrenic patients [23]. This high prevalence can be explained because even mild childhood trauma was included in the childhood trauma group.
The frequency of childhood adverse experiences in patients with schizophrenia varied across the studies [24,25,26,27,28]. It ranged from 50 to 94%. The disparities may be attributed to various reasons, including diverse demographics, multiple decades of assessment, disparate scales for evaluating childhood trauma, recall bias, sample size, and different countries and cultures. Additionally, other demographic characteristics may clarify the higher childhood trauma rates because childhood trauma questionnaires examine various experiences, the majority of which are linked to social status and educational level.
In the present study, the most frequent adverse childhood experiences were the mother, or household member treated violently (60.6%), emotional neglect (40.0%), physical abuse (25.5%), and contact sexual abuse (22.4%).
In a study of male patients with schizophrenia, the most often reported subtype of the adverse incident was psychiatric illness among family members (72.5%), followed by the separation, divorce, or mortality of the parents (58.8%), emotional negligence (54.9%), and physical neglect (43.6%). Sexual abuse and imprisonment of a family member were uncommon (19.6% and 29%, respectively) [27].
In a study of adults with Schizophrenia, Rosenberg et al. (2007) found that the most common form of adverse childhood event was child physical abuse (56%), followed by witnessing domestic violence (49%), parental separation, or divorce (36%), child sexual abuse (34%), and parental mental illness (21%) [28].
A meta-analysis study by Read et al. (2005) reported that psychotic patients had a high prevalence of childhood sexual and physical abuse. Sexual abuse was 48% among females and 28% among males. Physical abuse was 48% among females and 50% among males [6]. In addition, other pieces of literature reported that emotional abuse and neglect are more common in schizophrenia than physical abuse or neglect [25, 29,30,31,32].
We may explain the high prevalence of domestic violence in Egypt that violent behavior is typical against wives, especially in low socioeconomic status and a widely accepted cultural practice compared to high-income countries. Besides, the prevalence of recorded sexual abuse is somewhat lower in this study, primarily due to societal taboos and shame associated with child sexual abuse.
The current study found statistically significant negative correlations between total ACE score, educational level, and socioeconomic level. In agreement with the present study, Alvarez et al. (2011) and Schenkel et al. (2005) and found an association between childhood trauma and lower educational level, history of school difficulty, and these findings are similar to our results [8, 33].
In contrast, Vallejos et al. (2017) and Rosenberg et al. (2007) found no statistically significant difference in the level of education among patients who suffered multiple adverse events [27, 28]. A study done by Gil et al. (2009) showed that childhood trauma had no association with sociodemographic variables [34].
The current study found statistically significant negative correlations between total ACE score and age of onset of schizophrenia. These findings were in line with other literature [22, 25, 35,36,37,38]. The start of schizophrenia was earlier if the patients had been subjected to adverse childhood experiences. This result was significant only in cases of physical abuse within the abuse-specific subgroups [39].
Another study revealed that patients with a history of abuse, regardless of gender, have a significantly younger age of onset. In contrast, physical trauma appears to be a critical factor in accelerating the onset of schizophrenia, particularly in females [40]. In comparison, Rajkumar (2015) reported that age of onset was not correlated with the ACE scores [29].
There were statistically significant positive correlations between total ACE score and PANSS positive. In contrast, Longden et al. (2016) found a significant correlation between childhood trauma with positive symptoms and negative symptoms of schizophrenia. This difference from our study can be explained by studying the effect of different categories of childhood adversities on negative symptoms. This significant correlation is found with physical and emotional abuse only [41].
The current study found no statistically significant correlation between ACE score and WHODAS simple score. In agreement with our results, Rajkumar (2015) and Duhig et al. (2015) found that there was no significant relationship between childhood trauma and social, vocational, or overall functioning [29, 30].
On the other hand, Baudin et al. (2016), Gil et al. (2009), and Rosenberg et al. (2007) found that childhood trauma had an association with increased disability in adulthood presented by a statistically significant negative correlation between childhood trauma and overall functioning [34, 42]. This variation can be explained by different methodologies. Using the WHO Disability Assessment Scale criteria, impairment refers to interference in one's ability to function in six domains: cognition, mobility, self-care, getting along, life activities, and community participation.
Our study showed that there is no statistically significant correlation between ACE and medication adherence. In contrast, Lecomte et al. (2008) found that patients exposed to childhood trauma had lower compliance with treatment [43]. It can be explained by the presence of different variables influencing medication adherence. A robust familial support system following the first hospitalization has been found to deflect the impact of social and internalized stigma. Therefore, it can lead to a quicker recovery with greater ease in following treatment guidelines. Personal beliefs and attitudes about medication and psychiatric services have influenced treatment adherence and can be modified using cognitive-behavioral strategies. Also, specific personality traits, primarily being high in agreeableness, were linked to poor medication adherence. It can also be connected to a higher likelihood of being influenced by peers and eagerness to be accepted in a group and avoid social rejection linked to psychosis.
The current study found no statistically significant correlation between ACE score and frequency of hospitalization, which was consistent with other studies [22, 27]. In contrast, some studies revealed that a history of childhood abuse was associated with a more significant number of previous hospitalizations and earlier at first hospitalization [28, 33]. These findings may be explained by patients having difficulties recalling this detail since most participants in this study had been treated for several years; they could also be explained by subjects choosing not to share particular events, experiences, or personal behaviors [44].
The current study found statistically significant associations between the type of ACE and the characteristics of the studied patients. Yildirim et al. (2014) found that patients with primary school education were higher in patients with emotional neglect history [37]. Rajkumar. (2015) found that Childhood trauma was unrelated to one's childhood residence (rural or urban) and had no statistically significant correlation with overall years of education. And these findings were different from our findings [29]. Our result may be explained that rural areas have a lower social status and education level than towns. Thus, parents are preoccupied with earning a living and lack the time necessary to provide for their children, raising the likelihood of feeling neglected by their parents.
The prevalence of positive substance abuse screening in the studied patients was 18.2%. Almost three-quarters of them were positive for cannabis only, and the rest were positive for both cannabis and tramadol. There were statistically significant positive correlations between total ACE score and addiction severity index.
These results were consistent with Lasalvia et al. (2012), who found that 20.3% of schizophrenic patients were positive for substance abuse, and the most used drug was cannabis [45].
Besides, Margolese et al. (2004) found that 44.9% of schizophrenic patients fulfilled the criteria for lifelong drug misuse, and 14.0% fulfilled the criteria for current abuse/dependence and reported that the most often consumed drugs were alcohol and cannabis [46].
According to an Egyptian study by Asaad et al. (2003), 26% of schizophrenic patients met DSM-5 guidelines for drug misuse. Anti-parkinsonian medications were the most often abused substance, followed by cannabinoids, opioids, and benzodiazepines [47].
On the other hand, Swartz et al. (2006) incorporated radioimmunoassay of hair specimens and urine drug tests into diagnostic assessments combined with self-report measures. They reported that 37% of patients were diagnosed as having current substance use disorder [48].
The wide variance of the comorbid substance abuse prevalence in schizophrenia is based on the diagnostic evaluation techniques used, the presence of collateral informants, and the laboratory assessment techniques. Also, the high prevalence of alcohol misuse in western countries, which was not measured in this study, may lead to a high prevalence of substance use in other studies. Another cause for this variance is different cultures and legal constraints across countries.
Limitations: The cross-sectional design used by this study made it difficult to disentangle the effect of substance; for example, cannabis may result in psychotic experiences, but psychotic experiences may also result in the individual using cannabis to reduce the incidents of psychosis. So future longitudinal studies need to be done.
History of childhood trauma may also be associated with other co-morbidities, including post-traumatic stress disorder (PTSD), which may be targeted by specific psychotherapies, such as trauma-focused cognitive behavioral therapy. PTSD has not been evaluated in the present study, which is a clear limit and should be considered in further studies.
Our study lacked a control group, and we are therefore unable to comment on whether the patients in our sample experienced higher levels of childhood trauma or substance abuse than appropriately matched controls from the same population.