INTRODUCTION

Aggression and violence are serious problems that are becoming more and more visible in public discourse due to continuous development in media services and scientific research. Still, they are often wrongly portrayed, and therefore the perception of the general population continues to link most violence cases to mental health illness to an excessive extent while lacking scientific evidence to support this [1, 2]. However, violent events do occur in psychiatric healthcare regularly. Exposure to repeated or serious assaults, either through direct implication or vicarious incidents can leave negative traces on the healthcare workers' mental health, some of the personnel reported that after such events they started developing hypervigilance, anxiety, or even PTSD symptoms such as flashbacks. These experiences also negatively influence the personnel's motivation and interest in their daily duties and the workplace as a whole [3, 4]. Both in forensic and non-forensic services, medical staff with attention on nursing staff scored relevant levels of PTSD symptoms in relation to patient's disturbing behavior, of which violence towards others and self-injury were among the most impacting [5-7]. In a US study, approximately 70% of the clinical psychiatry staff workers reported having been assaulted in the previous year, leading to variable degrees of anger and depression [8].

A survey of US psychiatry residents focused on aggressive and violent events showed that up to 86% of the residents had received threats, and up to 71% had experienced physical intimidation, while 25% of them had experienced more serious incidents like physical assault. Additionally, more than half of respondents reported receiving unwanted advances, and a small minority reported experiencing inappropriate touching [9].

This review addresses several key aspects of this phenomenon for a better understanding and management of it.

Definitions

To be able to study the multi-dimensional implications of aggressive behavior, it is necessary to understand the meaning of the terms "aggression" and "violence". Human aggression is defined as any intentional act initiated by individuals, to injure or harm one or several other individuals, which would be normally motivated to avoid its effects [10].

The term "violence", however, would describe an act of aggression that has extreme harm as its end goal. Thus, violence could be considered a subform of aggression, with additional characteristics. Whether it causes physical injuries (eg. important pain, mutilation, body function loss, death) or serious psychological trauma in another person, in a group of persons, or even on the aggressor himself, the relation between action and its end goal demarcates violence from exclusively aggressive behavior. Therefore, according to the definition proposed by the WHO, suicide would also qualify as a violent act, considering de finality of the process [11, 12].

 

Incidence of Aggression in Psychiatric Units

A prospective study in which the gravity of the aggression was assessed using scales, shows that the majority of incidents were committed by rather a small number of patients compared to the total number (20 patients out of 855 caused 67% of the total incidents). In addition to this, the nursing staff turned out to be the most frequent victim. The study also shows that more serious incidents tend to be underreported in the official data, due to the staff tolerating a large number of aggressive incidents without signaling them [13].

Homicide

Although rarely happening in psychiatric facilities, there are several homicides cited in the literature. One study gathered clinicians who had contact with homicide cases committed by psychiatric inpatients. The case files also allowed the researchers to take into account other variables related to the event, such as the age, diagnosis, location, victim, method, and the offender's treatment before homicide. Summing up the data, the authors classify psychiatric patients into three groups with a particular risk of lethal assault: 1. acutely disturbed newly admitted patients, 2. undertreated patients with a history of serious violence during acute exacerbations of illness, and 3. patients with dementia or intellectual disability who are held in low-security settings [14].

Types of Aggression

 

The Bimodal Classification

One classification of aggression divides it into reactive and proactive aggression. The reactive type has an impulsive, hostile, and more defensive character, lacking premeditation. It has a considerable level of affection involved and it is mainly manifested abruptly, as a response to a more primal motif such as a perceived threat or emotional state (e.g. isolation, environmental factors, limitation of activities), manifested at a given moment. It involves an arousal that impairs cognition, resulting in behavioral outbursts. The other subtype, proactive aggression, similarly known as instrumental aggression, is usually rationally goal-oriented, as the offender is aiming for a given reward. It is more frequently initiated by the aggressor rather than a response to stimuli, and the degree of emotions involved in the reasoning and committing the act is variable [15-17].

In a study conducted on teenagers with high levels of aggression, instrumental and reactive-proactive aggression turned out to be negatively associated with affective and cognitive empathy, which strengthened the previous theories of emotional involvement, whereas, in the more reactive-aggressive subjects, a certain degree of empathy has been observed [18].

In certain cases, a dominant pattern of these two is manifested fitting the individual in a predominantly impulsive-hostile-affective aggression or a pattern of predominantly controlled-instrumental-predatory aggression, the latter one being less likely to refer to medical services [19].

By Target

Aggression and violence take place in different scenarios, involving a wide range of participants. Focusing on the characteristics of the offender-victim relation, WHO categorizes violence and aggression into self-direct abuse, in which the receiver and the aggressor are the same person (seen in autoregressive and suicidal behavior), interpersonal violence, in which aggression takes place between different individuals, and collective violence [12].

Neurobiology of Aggression

The two types of aggressive behavior seem to be controlled by different brain structures in animal models. According to A. Siegel, defensive aggression is mediated through stimulation of the medial hypothalamus (MH) or the dorsolateral region of the midbrain periaqueductal gray (PAG), while predatory attack behavior can be obtained through stimulation of the perifornical lateral hypothalamus (LH), ventral part of the PAG and dopamine-producing ventral tegmental region of the midbrain. Even though both pathways are under the control of the limbic structures, findings suggest that there is a reciprocal inhibition between LH and MH. This relationship allows either predatory attack or defensive rage to occur at a given time. Other studies on conditions of the limbic system such as temporal lobe epilepsy, sclerosis of the temporal lobe, tumors of the temporal lobe, other regions of the limbic system, and the hypothalamus correlate them with various forms of aggression dysregulation. This underlines the importance of the limbic formations in regulating aggression [20].

The three most probably involved neurotransmitters are serotonin (5-HT), norepinephrine (NE), and dopamine (DA), of which lower levels of serotonin seem to play the largest role in aggression, alongside lower levels of dopamine, determined poor control of impulsivity in animal models [21].

A disputed topic is the hereditary study of aggressive-prone personalities, with special regard to psychopathy. Several candidate genes have been proposed to be involved in the genesis of aggressive individuals. One of them is the Monoamine oxidase A (MAOA) gene, more precisely the MAOA-L allele, which is involved in low self-control, impulsivity, and negative emotionality, seen in individuals with antisocial traits [22].

Other candidate genes that add up to the risk of aggressive behavior through their influence on neurological pathways that modulate aggression are the 5HTTLPR and the MAOA-uVNTR, also associated with antisocial behavior [23]. The Catechol-O-methyl transferase (COMT), an enzyme responsible for the degradation of dopamine and norepinephrine, was identified to have a polymorphism (COMT Val158Met) that might lead to tendencies toward physical violence and increased aggressivity [24].

The General Context of Aggression

It is yet to be determined whether the psychiatric staff is the most susceptible to victimization. There is a debate about whether nursing staff or other patients are at higher risk of becoming victims [13, 25]. It has been shown that in the ER, the medical staff is not the primary target of aggression [26].

Increases in violence rates were reported during busy meals, medication, and shift change times if we consider the general circumstances in which aggressive or violent events do occur. These statistics could help determine whether severe assaults are unplanned, premeditated acts of predation or reactive, impulsive acts [25].

More severe aggressive incidents appear to happen during swing shifts. Additionally, the absence of clinical staff after regular working hours may have a say in the matter. Therefore, to prevent aggressive acts before they escalate, the afternoons and evenings may call for more structured activities or increased staffing [25]. The most prevalent mean of assault did not seem to differ from the ER compared to the ward, with punches being the most commonly used [26].

Triggers for Aggressive Reactions

A meta-analysis stated that in most of the cases, an interaction between the patient and staff was the cause for aggressive behavior (39% of all incidences involved an interaction between patients and staff members). Further analysis shows that limiting patients' freedoms (by physical restriction or request denial) was the leading cause for such reaction (approximately 25% of all antecedents). The request to smoke a cigarette was more frequently met, although other basic needs requests have also been involved in sparking an aggressive reaction. More notable was the denial of requesting to leave the ward, or requesting "off the ward privileges", which puts the closed-door policy under a question mark when dealing with potentially aggressive patients [27].

A longitudinal study addresses the open-ward versus closed-doors ward dilemma more directly, concluding that the type of hospital had no direct relation to the frequency of aggressive events. Considering the ward type, the results show that any accounted aggressive behavior during treatment had a significantly lower occurrence in open wards compared to locked wards, whereas the risk of damage to property and physical harm was increased in partially locked versus locked wards [28].

Considering the types of admission, patients who were involuntarily admitted to psychiatric hospitals would have a higher resistance dimension (hostility, uncooperativeness, suspiciousness) and would have a higher tendency to manifest hetero-aggressive behavior than those who were voluntarily admitted, the latter group however being more likely associated with auto-aggressive behavior [29].

Risk Factors

Younger patients, those having records of violent behavior, expressing intentions of harming others, who report having used psychoactive substances, who have a diagnosis of schizophrenia, schizoaffective disorder, intellectual disability, or bipolar disorder with manic symptoms have higher odds of manifesting aggressive behavior upon presentation in the ER [26].

Demographic Characteristics

Regarding age, different results have been reported in the literature. Some studies suggest that younger patients, within the 18–29 age group, have higher chances of being violent and those in the 18-29 and 30-39 intervals are more likely to commit assaults [30]. Other data suggest that older inpatients tend to be more aggressive to reduce social distance [31].

Although the literature provides us with information pointing towards male patients as being more aggressive than females [32], some studies that specifically analyzed the aggression exhibited by psychiatric inpatients reveal the opposite. In a 4-year longitudinal study in a Dutch forensic facility, where both civil and forensic psychiatric patients are admitted, the researchers noted that female patients were the most aggressive [33]. A meta-analysis of the demographic characteristics of aggressive psychiatric patients revealed that in non-forensic hospitals, aggressive behavior is exhibited more commonly by male patients, while in forensic hospitals the risk of these events was overcome by female patients [34]. In female patients, aggressive manifestations were more often exhibited to force compliance, to reduce tension, to obtain tangibles, or to seek attention [31].

There is some evidence suggesting that being unmarried is associated with higher aggressivity [34]. Also, the majority of the more aggressive individuals experienced psychiatric symptoms before they were teenagers [35].

Pathologies

Higher prevalence has been noticed in individuals diagnosed with a cluster B personality disorder [30]. Patients with Borderline Personality Disorder (BPD) and those with Antisocial Personality Disorder (APD) have the highest risks of becoming hostile and aggressive during hospitalization in psychiatric units [36]. APD is more strongly associated with instrumental aggressivity, while BPD has several traits linked to explosive violent behavior represented by anger, impulsivity, lower tolerance to threats, and defective interpersonal relationships [36, 37]. Antisocial patients use aggression as a tool to obtain an unfulfilled demand. Narcissistic personality disorder boosts the chances of exhibiting aggressive behavior, especially in those with low self-esteem or unstable high self-esteem [36].

Concerning psychosis, positive symptoms seem to play an important role in one's aggressive behavior. Studies show that higher levels of disturbance in one's social behavior, having severe auditory hallucinations, and being more thought-disturbed, are associated with a higher risk of aggression [31]. Antipsychotic medication has been shown to reduce aggressive behaviors in the aforementioned patients [26, 38, 39]. Comorbid substance use disorder was correlated with a higher prevalence of aggressive behavior [40]. In the ER, disorganization and paranoia were more commonly associated with assaults [26].

Substance abuse may also play an important role in some individuals manifesting aggressive behavior, although it frequently overlaps with other psychiatric disorders, and therefore studying its connection with behaviors is complicated by confounders. Alcohol may promote impulsive aggression by decreasing function in the frontal lobe and minimizing fear, thus precipitating more exaggerated and inappropriate responses in certain situations [41]. However, due to the lack of access to alcohol during hospital admission, violence in these in-patients is less frequent [42]. Substances with a high risk of developing psychosis have been observed in aggressive cases. Cocaine and other stimulants, such as amphetamines, together with cannabis, hallucinogenic drugs, or even steroid use were frequently incriminated in patients with violent or aggressive history [40-43].

Many of the patients with intellectual disabilities present to psychiatric units for different forms of aggressive behavior, both directed towards others or self-harm. Data from the literature suggests that both those who suffer from intellectual deficits from an early age and those with acquired cognitive loss later in life have higher odds of exhibiting physical aggression towards other patients or the medical staff [30]. Furthermore, the severity of the intellectual impairment correlates with the chances of developing physical aggression, boosted also by the presence of a comorbid psychiatric condition such as autism, psychosis, or depression [36].

Dementia is highly associated with aggressive behavior, especially if depression, anxiety, delirium, or psychosis are present [44, 45]. Although depression and psychosis are rarely comorbid with dementia, it seems that delirium stands out because of its high association with aggressive outbursts in hospitalized patients with dementia [45, 46].

Individuals with a diagnosis of unipolar depression were rarely involved in aggression incidents in the ER [26]. In most cases, aggression takes place during manic episodes, possibly due to prefrontal cortical dysfunction, especially if it is associated with mood-incongruent psychotic symptoms [36]. Compared with inpatients with schizophrenia or unipolar depression, those with schizoaffective disorder showed the highest rates of patient and staff-oriented acts of aggression [30].

History of Abuse and Self-Harm

According to a study on female patients from a forensic psychiatry unit, almost all of the patients in the high-aggression trajectory group had been removed from their homes before they were teenagers and most of them had experienced some form of sexual or physical abuse. These findings imply that many of these patients have been exposed to inappropriate environments as young children [35].

An association between a history of adversity early in life (foster care placements and trauma) and higher chances of involvement in criminal actions has been identified by some researchers. Such interaction could be based on the early development of poor coping mechanisms and maladaptive relational patterns towards other people and society, as a result of experiencing attachment disruption [47].

Higher levels of aggression and emotional dysregulation during admission were predicted by frequent records of self-harm, suicide attempts, and aggressive behavior in previous institutional settings [35].

Hospital Environment Factors

Some factors regarding unhygienic conditions in the ward, a poor living environment, a stressful atmosphere in the ward, or shortages of personal hygiene items have been identified by patients as problematic [48].

Regarding their fellow ward mates, the situations in which they were disturbing or provocative, or the case of patients with different diagnoses being placed in the same ward, as well as overcrowding, all contribute to various levels of dissatisfaction which can later contribute to manifesting aggression. As a result, if an optimal balance is maintained between density, privacy, and control, the chances of violent events are reduced [48].

Another aspect is the dissatisfaction felt by patients as a response to some inflexible limiting rules, change of rules depending on the ward, and lack of activities which led to boredom in the ward [48].

Staff who exhibited rigid, provocative, abusive, rude, or impatient attitudes, or who frequently neglected and ignored the patients’ needs were pointed out by them to be a cause of conflicts and outbursts of anger. In more serious cases, patients pointed out staff's bullying, intimidation, and threats (with injections, seclusion, or a return to the locked wards or delayed discharge) to fuel anger and aggression [48].

Coercive measures such as seclusion, although mandatory in selected cases, might hurt patients and further fuel their aggressive reactions [49].

Other Risk Factors

Dyslexia and neuropsychological impairment have been associated with a potential risk of violence. Cognitive impairment, in addition to older age and a history of suicide attempts during hospitalization, was associated with long-term chronic aggression.

More aggressive behavior was more likely to be displayed by patients who were socially reclusive to avoid engagement or activity and maintain their isolation. In contrast, patients who were diagnosed as depressed were more likely to act aggressively (for attention seeking) to close the social gap [31]. On the other hand, in forensic patients, an excessive degree of social isolation, such as the one imposed by the forced by SARS-Cov-2 pandemic, led to a rise in several violent behaviors which resulted in various types of trauma, at the peak of the pandemic.

Assessment of Aggression

Several measurement tools have been designed across time to evaluate aggression in patients. Some of the scales frequently used in psychiatry also asses aggression and agitation in patients, as a part of their overall structure. These composite scales, such as the Positive and Negative Syndrome Scale (PANSS), the Neuropsychiatric Inventory (NPI), or the Cohen– Mansfield Agitation Inventory (CMAI), could generally identify aggressive components in one's behavior, but they usually limit themselves to a few of them. A series of them have been summarized in the tables below (Tables 1 and 2).

Table 1. Scales used in aggression evaluation
Interpretation	Each of the 6 parameters is marked either 1=present or 0=absent. A score >2 indicates that the risk of violence is very high	The software calculates a risk score ranging from very low risk (Category 1) to very high risk (Category 5)	Each item is marked 1 if present or 0 if absent; A total score >3 represents a high risk of aggression	Scores ranging from 0 to 12; 4 groups: none (ABS = 0), moderate (ABS = 1, 2), severe (ABS = 3–5), and very severe (ABS = 6–12) [17]	Each parameter is scored from 0 to 4; A total weighted score ranges from 0 to 40, indicating the level of aggression	Each item is scored from 0 to 2; Higher overall scores indicate a higher risk of violence
Parameters	confusion, irritability, boisterousness, physical threats, verbal threats, and attacking objects.	items regarding the patient's behavior	irritability, impulsivity, unwillingness to follow directions, sensitivity to perceived provocation, anger when requests are denied, negative attitudes, verbal threats	physical abuse, socially inappropriate behavior, resisting care	verbal aggression, aggression against property, self-aggression, and physical aggression	10 historical factors (past) 5 dynamic clinical factors (present) 5 dynamic risk management factors (future)
Objective	predicts the risk of a violent incident	estimates violence risk after discharge	predicts the risk of aggression in the following 24 hours	frequency and number of aggressive behaviors in the previous 7 days	evaluates the severity of aggression in the previous week	evaluates the risk of a violent event
Type	observational	self-report software analysis	observational	observational	observational	self-report
Scale	The Brøset Violence Checklist (BVC)	Classification of Violence Risk (COVR)	T The Dynamic Appraisal of Situational Aggression (DASA)	The Aggressive Behavior Scale (ABS)	Modified Overt Aggression Scale (MOAS)	The Historical Clinical Risk Management-20 (HCR-20)

 

 

Table 2. Scales used in aggression evaluation
Interpretation	Each item is noted with 0 to 2 depending on how well it applies to the subject; the cut-off score of 30 indicates the presence of psychopathy	Scoring differs between items; scores vary from 0 to 61, with higher scores linked to greater levels of aggression	Evaluate aggressive events and their characteristics (scored from 0 to 4 according to the severity); the obtained score (2-12 pts.) marks the event as mild, moderate, or severe	A 3-point Likert scale rating from 0 to 2; items can be coded as strength or vulnerability; assessing evolution and helping in decision-making	The software calculates a risk ranging from 1% to 76% chance of committing a violent act in the following several months
Parameters	20 items based on subjective (emotion, attitudes) and objective information (history, behavior)	21 items regarding the presence, frequency, or severity of specific behaviors	5 aspects of Aggressive Events and Their Severity	20 dynamic risk and strength-related factors	several risk factors
Objective	evaluates psychopathy in individuals	assessing aggressivity level in elder patients on 3 days	assess the intensity and frequency of violent and assaultive acts from psychiatric and psychogeriatric in-patients	Evaluate risk to others, suicide, self-harm, self-neglect, unauthorized leave, substance abuse, and victimization Helps in treatment planning	predicts the likelihood of violence in patients
Type	observational and self-report (interview)	observational	observational	observational and self-report (interview)	self-report and observational (software)
Scale	Psychopathy Checklist-Revised (PCL-R)	The Rating Scale for Aggressive Behavior in the Elderly (RAGE)	Staff Observation Aggression Scale (SOAS)	Short-Term Assessment of Risk and Treatability (START)	Classification of Violence Risk (COVR)