What is aggressiveness?

  or without provocation. Human aggression can be classified as direct and indirect aggression, while the former is characterized by physical or verbal behavior intended to cause harm to someone. The latter is characterized by behavior designed to damage the social relations of an individual or group.

Almost all animal species carry out aggressive behaviors, which range from intimidating behaviors such as teeth grinding to direct attack, which in the case of humans can be both physical and verbal.

What is aggressiveness

The pattern of movements and postures that the animal carries out as an expression of its aggressiveness is different in each species and is highly genetically determined.

Most aggressi

ve behaviors are carried out for reproductive reasons, either directly (fighting the opponent) or indirectly, showing what they are capable of (egg, hunting).

Although this is the most common reason, aggressive behavior is also shown for other reasons such as defending the territory, obtaining food or as a defense.

When an animal carries out an intimidating behavior, the animal to which it is directed has two options, the first is to defend itself by attacking it as well, and the second is to show submissive behavior. The type of response depends on many factors in non-human animals, but in humans the thing becomes complicated and evens more factors such as self-esteem is added.

In non-human animal groups, bullying behaviors are more common than attacks, since it is clear which group member is stronger and who will be in a superior hierarchical position without the need to do harm or even kill, to any member of the group, which would have many negative consequences.

In studies carried out with animals it has been proven that the type of aggression they commit when they hunt is different from the aggressions produced to members of the same species.

When aggressive behavior is performed with the intent to hunt a prey is more rational and efficient, while if it is done with the intention of intimidating or attacking a member of the same species is much more violent and the animal becomes more active in doing so.

Aggressiveness in humans

After reading the above comment it seems that aggressiveness is a clearly adaptive behavior, but this is so only in nonhuman animals. In humans it is a serious social problem.

To illustrate the problem I will present a case presented by Holden in his article The Violence of the Lambs:

“The son of an alcoholic and teenage mother who left him with an alcoholic and abusive stepfather, Steve was hyperactive, irritable and disobedient as a child … After dropping out of school at age 14, Steve spent his teens fighting, stealing, taking drugs and hitting to her girlfriends … School counseling, her probation officer and child protective services meetings were unable to prevent the disaster: At age 19, a few weeks after her last interview with investigators, Steve visited a girlfriend who had cut with him recently, found her with another man and shot him several times until he was killed. The same day he tried to kill himself. Today he is serving a life sentence without parole. “

Steve’s case is extreme, but there are many cases of adults who have had a complicated history during their childhood or adolescence and who nowadays present aggressive behavior. Apart from the story itself, there are other variables that affect the level of aggressiveness that each person presents, such as temperament or genetic and biological factors.

Factors Affecting Aggressiveness


According to the Regulative Theory of Streak Temperament, temperament functions as a modulating variable between biological factors and behavior.

It has a high genetic component, but is also affected by environmental variables such as experience.

It manifests itself in any type of behavior, i.e. everything we do we do with the same temperament, therefore it is highly stable. Although the degree of stability depends on each person.

Temperament is defined by the energetic and temporal components of behaviors:

  • Energy components
  • Reactivity: is defined as the intensity and magnitude of reactions to the stimuli.
  • Activity: amount and level of activity required to reach the optimum level of stimulation.
  • Temporary components
  • Vivacity: speed at the beginning of the action.
  • Perseverance: time that keeps the response until it is extinguished.

Aggressive people have greater reactivity to the stimuli and need less energy to reach their optimal level of stimulation, so they would also respond faster.

Essence also developed an interesting theory about temperament, the Biofactorial Theory. The study carried out to corroborate this theory consisted of two parts; firstly, it elaborated a classification of traits according to the type of temperament, and, secondly, correlated them with some biological markers.

His first categorization was formed by neuroticism; extraversion and sincerity, later also included psychotics.

According to this theory, aggressiveness would be included within the extroverted personality type, in addition to other features represented in the following graph.

Graph 1In the second phase found a correlation between this type of personality and other factors, being aggressiveness a feature of this personality type, it is considered that there is also a relationship between these factors and aggressiveness.

Biological factors

Some studies have found features in the brains of aggressive people that differentiate them from non-aggressive ones. Below are some results obtained?

The serotonin plays an important role in modulating aggressive behavior. Specifically, it appears to inhibit this type of behavior, so that low levels of serotonin would be related to aggressive behaviors and other types of antisocial behaviors.

If the above hypothesis is true, then taking drugs that increase serotonin levels may decrease aggressive behaviors. A study conducted by Cicero and Kaposi (1997) found that participants given fluoxetine (a serotonin enhancer) had less irritability and aggressiveness than at the beginning of the study.

Other researchers have focused on relating violent behaviors to emotional regulation.

When we feel frustrated or angry we feel like engaging in aggressive behavior, but we usually control them and try to calm ourselves down. It may be that the problem of aggressive people resides there, that they cannot control their emotions and thoughts when they are frustrated and carried out.

The ventromedial prefrontal cortex plays an important role in modulating our response to stimuli or frustrating situations. Although this process cannot depend entirely on this area because to carry out it is necessary to perform a sensorial @nalysis of the stimulus, make an inference about what it means for us, taking into account our previous experiences (own and the people around us) , make a judgment of what response we must give, etc.

The ventromedial prefrontal cortex is connected to areas of the brain that control the processes necessary to control our response to frustrating stimuli, such as the hippocampus (essential for memory), sensory areas, the amygdale (important to give an emotional sense to experiences). Possibly the importance of the ventromedial prefrontal cortex is determined by its connections with other areas.

There are cases that demonstrate the importance of this area, in fact one of them is possibly the best known case in the world of psychology, and I am talking about the case of Phones Gage.

Phones worked as a foreman in the construction of a railway line, but one day an accident happened that would change his life. Phones was using an iron rod to put gunpowder in a hole when the gunpowder exploded and the rod pierced his head, entering through the cheekbone and out through the frontal cortex.

Miraculously, Phones survived the accident, but his relatives and close associates noticed a noticeable change in his behavior. He had always been a serious and responsible man, but after the accident he became childish, irresponsible, irritable, and it seemed that the others did not care at all.

The doctors observed on an MRI that the accident had almost completely destroyed the ventromedial prefrontal cortex. Throughout history many other cases of people with damaged ventromedial prefrontal cortex have been studied and in all have been observed symptoms similar to those of Phones.

The most remarkable symptom of these people is that they are unable to make decisions that involve moral or ethical dilemmas in an efficient way. The evidence obtained in all studies to date suggests that the ventromedial prefrontal cortex serves as a nexus between the brain areas related to automatic emotional responses and those related to the control of complex behaviors.

It may appear that these symptoms do not have much to do with aggressiveness, but if the emotional inputs from the amygdale are not modulated, aggressive anger-induced behaviors can occur. In fact, in a study by Rained (2008) in which the participants were murderers, they were found to have a hyper activation of the amygdale and a hypo function of the prefrontal cortex , which could explain that they identify more stimuli as negative and that are not able to control those negative emotions, thereby leading to aggressive behavior.

The explanatory hypotheses of the aggressiveness I mentioned in this section, the low levels of serotonin and a hypo function of the prefrontal cortex, are not exclusive, in fact, they support each other since the prefrontal cortex receives many serotoninergic projections and it is believed that these projections activate this area and this area, in turn, inhibits the amygdale. So if the serotonin levels go down the prefrontal cortex will be activated less and the amygdale will be activated more.

Aggressive-related disorders

There are a number of disorders in which the aggressive component is especially important; these are encompassed in DSM-5 within Disruptive Disorders of Impulse Control and Behavior.

These disorders imply a problem in the control of the behavioral and emotional impulses. They are more frequent in men than in women and in extroverted and uninhibited people and appear from childhood.

Many of the aggressive behaviors observed in children are due to these disorders.

Challenging Negative Disorder

Children and adolescents who suffer from this disorder are characterized by a hostile, disobedient, defiant and negative attitude toward authority figures (parents, teachers …).

The behavior of these people causes great discomfort in the people around them, but they do not seem to care because they do not think they have a problem and do not see themselves as responsible for the acts they comment on.

This disorder is more frequent in families where the parents are very controlling and carry out authoritarian educational practices.

The diagnostic criteria of DSM-5 are as follows:

  1. A pattern of anger / irritability, arguments / defiant or vengeful attitude that lasts for at least six months, manifested by at least four symptoms of any of the following categories and which is exhibited during interaction with at least one individual who do not be a brother.

Anger / irritability

  1. He often loses his temper.
  2. Often susceptible or easily disturbed.
  3. He is often angry and resentful.

Discussions / defiant attitude

It often argues with authority or with adults, in the case of children and adolescents.

Often actively challenges or refuses to satisfy the request by authority figures or standards.

He often molests others deliberately.

Often blames others for their mistakes or misbehavior.


Has been spiteful or vengeful at least twice in the last six months

Note: The persistence and frequency of these behaviors should be considered in order to distinguish those that are considered within the normal limits of the symptomatic ones. In children with destructive and behavioral disorders less than five years of age, behavior should occur almost every day for at least six months, unless otherwise noted (Criterion A8). In children five years of age or older, behavior should appear at least once a week for at least six months, unless otherwise noted (Criterion A8). Although these frequency criteria are considered the minimum guideline to define the symptoms, other factors should also be taken into account, for example,

  1. This behavioral disorder is associated with discomfort in the individual or others in the immediate social environment (i.e. family, group of friends, co-workers) or has a negative impact on the social, educational, professional or other areas important.
  2. Behaviors do not appear exclusively in the course of a psychotic disorder, a substance use disorder, a depressive disorder or a bipolar disorder. In addition, the criteria for a mood disturbing deregulation disorder are not met.

Specify current severity:

Mild: Symptoms are limited to an environment (egg, at home, at school, at work, with peers).

Moderate: Some symptoms appear in at least two environments.

Severe: Some symptoms appear in three or more environments.

In order to treat this disorder it is essential that the parents engage in the therapy and that they carry out the advice that the professional gives them also at home. Individual therapy is usually combined with family therapy.

Intermittent Explosive Disorder

People who suffer from this disorder have repeated episodes of lack of control in which they are impulsive, aggressive and violent. They react disproportionately to frustrating situations.

In these episodes they can destroy objects and attack other people or themselves causing injuries.

Unlike people with challenging negativist disorder, these people do tend to realize what they have done later and feel regret and shame.

This disorder is common in children with parents who also exhibit explosive behavior and it is very likely that genetic and biological components will also influence.

The diagnostic criteria according to DSM-5 are the following:

  1. Recurring behavioral reactions that reflect a lack of control of impulses of aggressiveness manifested by one of the following:
  2. Verbal aggression (egg, tantrums, tirades, verbal quarrels or quarrels) or physical aggression against property, animals or other individuals, on average twice a week, over a period of three months. Physical aggression does not cause damage or destruction of property, nor does it cause physical injury to animals or other individuals.
  3. Three outbursts in behavior that cause damage or destruction of property or physical aggression with injuries to animals or other individuals, which occurred in the last twelve months.

The magnitude of aggressiveness expressed during recurrent outbursts is quite disproportionate to provocation or any triggering psychosocial stressor.

  1. Recurrent aggressive outbursts are not premeditated (i.e. impulsive or anger-provoked) or pursue any tangible goal (egg, money, power, intimidation).

3 – The recurrent aggressive outbursts because marked discomfort in the individual, alter their work performance or their interpersonal relationships, have economic or legal consequences.

4- The individual has a chronological age of at least six years (or an equivalent degree of development).

5 – Recurrent aggressive outbursts are not better accounted for by another mental disorder (egg, major depressive disorder , bipolar disorder , mood disturbing deregulation disorder, psychotic disorder, antisocial personality disorder , borderline personality disorder ) , nor can they be attributed to another medical condition (egg, head trauma, Alzheimer’s disease ) or to the physiological effects of a substance (egg, drug addiction, medication). In children between the ages of 6 and 18, aggressive behavior that is part of an adjustment disorder should not be assigned this diagnosis.

Note: This diagnosis can be established in addition to the diagnosis of attention deficit disorder with hyperactivity, behavioral disorders, challenging negativistic disorder or autism spectrum disorder, when recurrent impulsive aggressive outbursts exceed those usually observed in these disorders and require independent clinical care.

It is very important that the treatment focuses on impulse control, first guided, and that the patient is gaining autonomy so that he himself can be controlled in such situations. In the most severe cases psychotherapy and medication are usually combined.

Behavioral Disorder

People who suffer from this disorder engage in repeated behaviors in which they do not take into account the rights of others or social norms (or established by the authorities).

There are four patterns of behaviors that can be differentiated within this disorder:

  • Aggressive behavior.
  • Destructive behavior.
  • Scam.
  • Rule transgression.

This type of disorder is frequent in unstructured families or in children who have spent large seasons changing caregivers or in a juvenile center.

The diagnostic criteria according to DSM-5 are the following:

A repetitive and persistent pattern of behavior in which the basic rights of others, norms or social rules of age are not respected, which is manifested by the presence in the last twelve months of at least three of the fifteen criteria following categories, with at least one in the last six months:

(Criteria 1-7), destruction of property (criteria 8 and 9), deception or theft (criteria 10-12) and serious breach of standards (criteria 13-15):

Aggression to people or animals

  1. Often harasses, threatens, or intimidates others.
  2. Often starts fights.
  3. He has used a weapon that can cause serious damage to others (egg, a cane, a brick, a broken bottle, a knife, a weapon).
  4. He has exercised physical cruelty against people.
  5. He has exercised physical cruelty against animals.
  6. He has stolen from a victim (egg, robbery, theft of a purse, extortion, armed robbery).
  7. He has sexually raped someone.

Destruction of property

He has deliberately set himself on fire with the intention of causing serious harm.

He has deliberately destroyed someone’s property (but not through fire).

Cheating or theft

He has invaded someone’s house, building or car.

He often lies to get objects or favors, or to avoid obligations (egg “cheats” others).

He has stolen non-trivial valuables without confronting the victim (egg, shoplifting without violence or invasion, forgery).

Serious breach of standards

He often goes out at night despite his parents’ prohibition, starting before age 13.

You have spent a night away from home without permission while living with your parents or in a foster home, at least twice or once if you were absent for a long time.

Often missed at school, starting before age 13.

Behavior disorder causes clinically significant discomfort in the social, academic or work area.

If the age of the individual is 18 years or older, the criteria for antisocial personality disorder are not met.

Specify if:

312.81 (F91.1) Childhood onset type: Individuals exhibit at least one characteristic symptom of behavioral disorder before the age of 10.

312.82 (F91.2) Type of adolescent onset: Individuals do not show any characteristic symptoms of behavioral disorder before reaching age 10.

312.89 (F91.9) Unspecified onset type : Criteria for conduct disorder are met, but insufficient information is available to determine if the onset of the first symptom was earlier than 10 years of age.

Specify if:

With limited prosaically emotions: In order to assign this specified, the individual must have presented at least two of the following characteristics persistently for at least twelve months in various relationships and situations. These characteristics reflect the typical pattern of interpersonal and emotional relationships of the individual during that period, not just occasional episodes in some situations. Therefore, to assess the criteria of a particular specified, several sources of information are needed. In addition to the individual’s own communication, it is necessary to consider what others have said that have known him / her for extended periods of time (egg, parents, teachers, co-workers, family, friends).

Also Read: Altruism: Characteristics, Theories and Advantages

Lack of remorse or guilt: Do not feel bad or guilty when you do something wrong (do not count the remorse that expresses only when surprised or a punishment). The individual shows a general lack of concern about the negative consequences of their actions. For example, the individual does not feel remorse after harming someone or worries about the consequences of breaking rules.

Insensitive, devoid of empathy: Does not consider or care about the feelings of others. This individual is described as cold and indifferent. The person seems more concerned about the effects of his actions on himself than on others, even when they cause appreciable damages to third parties.

Concerned about your performance: Do not show concern about deficient or problematic performance at school, at work or other important activities. The individual does not make the effort necessary to achieve good performance, even when expectations are clear, and often blame others for their deficit performance.

Shallow or Poor Affection: Does not express feelings or shows emotions with others, except in a way that seems unhealthy, untruthful or superficial (egg, with actions that contradict the expressed emotion, can “connect” or “disconnect” the emotions quickly) or when you use emotional expressions to gain benefits (egg, expressing emotions to manipulate or intimidate others).

As in the rest of the disorders, for the therapy to work, it is essential that both the patient and the people around him commit to follow the advice of the professional. If the problem persists due to the family it may be necessary to separate the child.

Antisocial Personality Disorder

This disorder is within the group B group of personality disorders in DSM-5, this group includes over extrovert, emotional, impulsive, and unstable individuals.

Unlike the above, this disorder can only be diagnosed to adults.

The diagnostic criteria according to DSM-5 are the following:

A general pattern of contempt and violation of the rights of others that is presented from the age of 15, as indicated by three (or more) of the following items:

Failure to adapt to social norms in regard to legal behavior, as indicated by repeatedly perpetrating acts that are grounds for arrest

Dishonesty, indicated by lying repeatedly, using an alias, defrauding others for personal gain or pleasure

Impulsivity or inability to plan for the future

Irritability and aggressiveness, indicated by repeated physical fights or aggressions

Reckless care for your safety or that of others

Persistent irresponsibility, indicated by the inability to keep a job with constancy or to take charge of economic obligations

Lack of remorse, as indicated by the indifference or justification of having damaged, mistreated or robbed others.

Subject is at least 18 years old.

There is evidence of a behavior disorder that begins before the age of 15 years.

Antisocial behavior does not appear exclusively in the course of schizophrenia or a manic episode.

There is great co morbidity of this disorder with substance abuse; therefore, therapy begins by treating bad habits that may be aggravating the problem.