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The Causes of Aggression

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Everyone becomes aggressive at times. However, in the setting of other physical symptoms or illness, aggressive tendencies can be representative of an illness.

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Aggression symptoms

As fallible human beings, we are all prone to a burst of aggression now and then. Friends don't get along, coworkers get into it, and families fight. Rage and aggression are never pleasant emotions, and most of us always reflect back negatively on when we "lost control" or yelled at another person. But most of these experiences are transient, thankfully, and we are able to regain our composure, apologize, and move on.

Unfortunately, that is not the case for all people. For one reason or another, some people are more prone to angry outbursts. When these bouts of aggression start to interfere with their everyday relationships and functioning, it's time to get some professional help. This is especially true if a person has a sudden personality change or becomes aggressive all of a sudden while sick as such acute changes can represent serious medical conditions and mild forms of brain dysfunction.

If you feel unsafe, seek emergency care

If a person's aggression becomes threatening or violent, remember the number one rule is to be safe. If you feel unsafe or threatened, it is time to get law enforcement involved. Aggression can not only harm others, but the aggressor themselves, and so maintaining control of the situation is critical.

Common accompanying symptoms of aggression

Aggression may be associated with these common symptoms:

  • Feelings of anger, frustration, or fear
  • Violent behavior
  • Functional impairment
  • Poor interpersonal relationships
  • Difficulty thinking or performing everyday tasks

Aggression causes

Most everyone becomes frustrated, angry, and aggressive at one point in their lives. Some people, however are quicker to anger, more prone to aggression, are less able to control their aggression, or are chronically unable to control their emotions effectively. When such negative behavior is pervasive, it may represent an underlying psychiatric or personality disorder. In the setting of other physical symptoms or illness, this may be representative of an illness negatively impacting brain function.

Psychiatric causes

Aggression may be cause by psychiatric causes such as the following.

  • Personality disorder: Certain personality disorders leave people with higher levels of aggression than others.
  • Psychiatric disorders: Some psychiatric disorders can cause delusions or aggression.

Neurologic causes

Aggression may be related to certain neurologic causes, such as the following.

  • Dementia: Breakdown of certain parts of the brain, usually due to aging or genetic disease, can lead to changes in behavior, memory, and aggression.
  • Brain lesions: Tumors or infections of the brain can lead to behavior changes.
  • Autoimmune: Rarely, your body's immune system may inappropriately attack parts of the brain, leading to aggression.

Systemic causes

You may be experiencing aggression due to systemic causes, such as the following.

  • Drug or alcohol intoxication: High doses of alcohol, drugs, or medications may lead to psychosis and aggression. Withdrawal from these drugs can cause similar symptoms.
  • Severe infection: Severe infection can lead to confusion and aggression.
  • Blood loss: If a person loses too much blood (anemia), less oxygen is able to get to the brain, causing alterations in behavior.
  • Metabolic: Imbalance of key electrolytes and hormones can lead to alterations in behavior.
  • Environmental exposure: Certain toxins or other environmental exposures can cause confusion and aggression.

9 conditions of aggression

This list does not constitute medical advice and may not accurately represent what you have.


Schizophrenia is a mental illness that causes people to lose touch with reality (called psychosis). People with schizophrenia may have hallucinations (like hearing voices) and delusions (fixed beliefs that aren’t true). They may have trouble keeping their thoughts straight, feel a lack of motivation, and not express much emotion. These symptoms greatly impact work and relationships.

Schizophrenia affects roughly 1% of the population. It occurs equally in men and women but tends to appear earlier—usually in the teen years—in men. It is often diagnosed between teen years and early 30s.

Schizophrenia is a lifelong illness that requires medication. Symptoms come and go over time. Early diagnosis and treatment can lead to greater improvements in symptoms.

Post-traumatic stress disorder (PTSD)

Post-traumatic stress disorder (PTSD) is a disorder that develops as a reaction of trauma. One can get PTSD after living through or seeing a traumatic event, such as war, a hurricane, sexual assault, physical abuse, or a bad accident. PTSD causes stress and fear after the danger is over.

PTSD should be managed by a psychiatrist. If you have not been seen for your symptoms, go to your PCP for a referral immediately. Diagnosis is clinical while treatment involves different medications (possibly) and psychotherapy.

Rarity: Common

Top Symptoms: psychological or physiological distress

Urgency: Primary care doctor

Post-concussion syndrome

Concussion symptoms tend to last for a few days to weeks. Sometimes, symptoms are long term, lingering for several months or even years. This is known as post-concussion syndrome (PCS). Some of the most common PCS symptoms include headaches and confusion. Memory problems and difficulty concentrating may also occur.

You should consider visiting a medical professional in the next two weeks to discuss your symptoms. A doctor can evaluate PCS with a review of your symptoms and an MRI. Once diagnosed, treatment depends on your specific symptoms but often focuses on letting the brain rest and recuperate. You may be asked to temporarily stop sports and exercise until you are cleared to return.

Obsessive-compulsive disorder (OCD)

Obsessive-compulsive disorder (OCD) is a type of anxiety disorder. As the name suggests, it involves both obsessions and compulsions. Obsessions are intrusive upsetting thoughts often relating to specific themes like cleanliness, symmetry, or sometimes even taboo thoughts that might be sexual or violent in nature. Compulsions are repetitive behaviors that the individual feels driven to perform, and are often related thematically to the obsessions.

Patients with obsessive-compulsive disorder should see a psychiatrist or therapist in order to confirm the diagnosis. If confirmed, it can be treated with medications such as SSRIs (selective serotonin reuptake inhibitors), as well as a kind of therapy called cognitive behavioral therapy.

Rarity: Rare

Top Symptoms: impaired social or occupational functioning, anxiety, aggression, anxiety resembling obsessive-compulsive disorder, repetitive patterns of behavior

Symptoms that always occur with obsessive-compulsive disorder (ocd): anxiety resembling obsessive-compulsive disorder, impaired social or occupational functioning

Urgency: Primary care doctor

Mild bipolar disorder i

Bipolar disorder is a common, lifelong mental health condition of variable severity that can run in families, characterized by episodes depression and mania that last for weeks or months.

Symptoms often start in adolescence or young adulthood. Mania is a state of elevated or irritable mood, with changes in behavior, such as decreased need for sleep, increased goal-directed and risky activities, and increased talkativeness. Depressive episodes in bipolar disorder are like major depression, characterized by low mood, loss of pleasure, and low energy. Mood episodes are separated by periods of remission with stable mood and minimal difficulties with daily function.

Treatment for bipolar disorder varies from person to person, depending on symptoms and other individual factors. It often consists of medications such as mood stabilizers and antipsychotics that help reduce extreme symptoms. Hospitalization may be recommended in acute episodes. Psychotherapy can also be helpful.

Rarity: Rare

Top Symptoms: fatigue, irritability, depressed mood, difficulty concentrating, trouble sleeping

Symptoms that always occur with mild bipolar disorder i: periods of feeling very energetic and needing little sleep

Urgency: Primary care doctor


Moderate depression, also called dysthymia or dysthymic disorder, is one of the three general forms of : mild, moderate, or severe. About half of all people suffering from have the moderate form.

The causes of any depression are not known for sure. Some may be situational, such as grief or other difficult life events. Others may be due to physiological causes such as chemical or hormonal imbalances.

Symptoms include loss of interest in normal activities; neglect of activities of daily living; and loss of productivity, though the person will continue going through the motions of attending work or school.

If not treated, moderate depression can worsen into major depression.

Diagnosis begins with physical examination and blood tests to rule out any physical causes. A mental health professional will talk to the patient to learn about any difficult situational factors.

Treatment may or may not involve antidepressant medication, since antidepressants generally work best for severe depression. Psychotherapy, exercise, relaxation techniques, and lifestyle improvements are usually tried first for moderate depression, and are often very effective.

Rarity: Common

Top Symptoms: fatigue, depressed mood, headache, anxiety, irritability

Symptoms that always occur with depression: depressed mood

Urgency: Primary care doctor

Conduct disorder

Conduct disorder refers to a group of behavioral and emotional problems in young people. Children and adolescents with this disorder have difficulty following rules and behaving in a socially acceptable way. May factors may contribute to this disorder, including brain damage, child abuse, genetic vulnerability, school failure, and traumatic life experiences.

You should visit your primary care physician who will coordinate care with a child psychiatrist. Treatment usually involves behavior therapy and psychotherapy to help you learn to appropriately express and control anger.

Rarity: Rare

Top Symptoms: tendency to often break rules, deception, aggression and serious threats of harm

Urgency: Primary care doctor

Borderline personality disorder

Borderline personality disorder is a personality disorder, or a persistent abnormal behavior pattern manifesting during childhood or adolescence, involving unstable mood and relationships, unstable self-image, and recurrent self-harm or suicidal behavior. Factors contributing to the development of borderline personality disorder include genetic factors, environmental factors, changes in brain circuitry, and hormonal imbalances.

Alzheimer's disease

Alzheimer's disease is a progressive neurological disorder that slowly destroys memory and the ability to think clearly. As symptoms worsen, patients are often unable to perform basic tasks.

You should visit your physician to discuss these symptoms. It is likely tests will be ordered to better diagnose you.

Rarity: Common

Top Symptoms: trouble sleeping, forgetfulness, anxiety, aggression or confusion, anxiety, irritability, depressed mood

Symptoms that always occur with alzheimer's disease:forgetfulness, anxiety, aggression or confusion

Urgency: Primary care doctor

Aggression treatments and relief

Often, feelings of aggression can be diffused through common coping mechanisms. However, when someone is chronically quick to anger, unable to control their anger, or is overly aggressive, it may be time to seek professional help. If someone becomes aggressive in the context of a traumatic injury or illness, they should be taken to a hospital for treatment as this may be a manifestation of that illness.

At-home aggression treatments

If you're dealing with aggression, consider the following methods for calming yourself or another person down.

  • Take a deep breath: Many people find it beneficial to take a deep breath before reacting impulsively to a situation. If you are feeling angry or aggressive, consciously taking a moment to think can help control your emotions.
  • Remove yourself from the situation: If you feel unable to control an angry outburst or are extremely frustrated, it can be helpful to take a quick step out or get away from the thing causing you anger.
  • Reflect: Try to put yourself in the other person's shoes. Empathy and attempting to understand what another person is thinking and where they are coming from can help put situations in perspective.
  • Rest: Sleep is the great equalizer. Intense emotions are processed during sleep, and people often wake up with more calm and rational perspectives after a nap or a good night's sleep.
  • Be safe: If someone around you is acting aggressively, try and exit the situation. If you are unable to or if you feel physically threatened, call law enforcement to ensure your safety.

Professional aggression treatments

If aggressive episodes have gotten progressively worse or are persisting, it is time for professional help.

  • Therapy: Various types of therapy services are quite effective at managing aggression and other negative personality traits, or the illnesses by which they are caused. Therapy sessions are often individual but may occur in groups as well.
  • Medication: Some medications can be used to treat psychiatric illness, or other causes of new-onset aggression.

When aggression is an emergency

You should seek help without delay if you or someone you know is experiencing:

  • Violent behavior
  • Loss of control
  • Difficulty thinking or poor cognition
  • Recent drug or alcohol use
  • Recent traumatic injury
  • Fevers or chills

FAQs about aggression

Here are some frequently asked questions about aggression.

Why are some Alzheimer's patients aggressive?

One of the most common symptoms associated with Alzheimer's Disease is memory impairment. However, other symptoms may appear earlier. Visuospatial impairment, or inability to discriminate between the locations of objects in space; and executive dysfunction, including tasks like self control, controlling aggression, and deficits in language and ability to perceive cultural or behavioral norms may appear first. Ability to control aggression is managed primarily by areas within the frontal cortex, which may be damaged by dementia far before symptoms of memory loss appear.

What increases aggressive behavior?

Increases in aggressive behavior can be triggered by a lack of impulse control, which can be triggered by substances that impair judgement like drugs and alcohol, a blow to the head impairing those same judgement centers, increased activation of the aggression center which can, again, be triggered by drugs and alcohol or even social and behavioral situations. Lack of sleep or existing in a space where an individual no longer believes they need to control aggression are common reasons why aggressive behavior may increase.

What are some examples of aggressive behavior?

Aggressive behavior can include open hostility like yelling, throwing objects, or physical altercations. Hostility can also include advancing toward a person, threatening hand gestures, or brandishing an object as a weapon.

Why is my child overly aggressive?

Most commonly, irritable or aggressive children may be missing sleep. Sleep deprivation can cause symptoms of depression or conduct disorders. Additionally, undiagnosed attention-deficit hyperactivity disorder can lead to aggression in some children, especially if they are under stress to perform well at school or at home.

What causes a sudden onset of aggressive behavior?

A sudden onset of aggressive behavior can be caused by many different substances, including drugs and alcohol, as well as age-related dementias like Alzheimer's. Individuals may be more aggressive if they have a sudden onset of a psychological condition like schizophrenia or a long term lack of sleep.

Questions your doctor may ask about aggression

  • Are you having difficulty concentrating or thinking through daily activities?
  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Are your symptoms causing difficulty at work, socializing, or spending time with friends & family?
  • Do you have trouble sleeping?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Hear what 1 other is saying
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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Random outburstsPosted September 11, 2021 by M.
Been having behavioral issues with aggression for about a year. Not sure what the underlying issue is, but I have been overly aggressive with everyone in my circle including co-workers and family. Not sure how to combat this, but my temper is way out of proportion compared to my stressors. Is it possible these reactions are a manifestation of feeling helpless or out of control?
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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