The incredible violence that characterizes the tragic events perpetrated by Pierre Ny St-Amand, 51, in the Sainte-Rose district of Laval, Steeve Gagnon, 38, in Amqui, and Arthur Galarneau, 19, in the Rosemont district of Montreal , indicates that, presumably, the brains of these individuals were derailed at the time of the facts.
Various pathologies of the brain could have led to these dramas which go beyond understanding. “These three cases seem very different from each other,” says Dr.D Stéphanie Borduas-Pagé, forensic psychiatrist, medical head of the forensic psychiatry department at the Mental Health University Institute of Montreal.
Several conditions, such as schizophrenia, toxic psychosis, bipolar disorder, depression, or even more organic disorders, such as brain tumor, encephalitis, or dementia, can cause psychotic symptoms where the person may lose contact with the reality and be invaded by hallucinations and delusions likely to induce disorganized, even violent behavior, notes the DD Borduas-Page.
Unlike schizophrenia, which is a chronic disease that begins insidiously at a fairly young age, toxic psychosis can occur suddenly. Psychosis and the effect of the substance itself can increase irritability, decrease ability to manage anger, to inhibit oneself.
This insists on the fact that “the majority of people with schizophrenia or another of these pathologies do not present a risk of violent behavior when they are followed, treated and their symptoms are well controlled”.
“It’s more the acute and active symptoms [qui se manifestent quand la personne n’est pas suivie ou ne prend pas sa médication] which are likely to induce violent acts. A schizophrenic patient [qui vit un épisode psychotique] may be convinced that his life is in danger and that people are trying to control his thoughts and actions. He then experiences such great distress that he may feel the need to defend himself against this threat he perceives. He may also have hallucinations that order him to make gestures towards others, but also towards himself, because around 10% of schizophrenics will die by suicide”, explains the clinical professor in the Department of Psychiatry and Addiction at the University of Montreal.
The young man who stabbed three members of his family in Rosemont was probably suffering from psychosis resulting from a psychiatric illness when he perpetrated three violent murders, because he had already been followed for mental health problems.
The use of drugs, such as cocaine, amphetamine, methamphetamine, crack and its derivatives, even cannabis and alcohol, can sometimes lead to psychotic symptoms. This is called toxic psychosis. “These drugs are often taken for their effects on the brain, in particular altering the function of the frontal lobes which are very much linked to behavior and motivation. Our ability to control our impulses, to keep them within a certain limit, is all managed by the frontal lobes. Anything that can lead to an imbalance in these frontal lobes can induce strange, or extreme, or uncontrolled behaviors. The person can become very uninhibited, inappropriate, and make decisions that are not based on reality and that are not in line with social norms”, underlines the Dr Étienne de Villers-Sidani, neurologist at The Neuro (Montreal Neurological Institute-Hospital).
“Unlike schizophrenia, which is a chronic disease that appears insidiously at a fairly young age, toxic psychosis can occur suddenly,” adds Dr.D Borduas-Page. Psychosis and the effect of the substance itself can increase irritability, decrease ability to manage anger, to inhibit oneself. […] Whether you have a diagnosis of mental illness or not, substance use will increase the risk of violence. »
Toxic psychosis therefore appears to be a possible diagnosis for Steve Gagnon, from Amqui, given that he did not seem to have a psychiatric history.
Organic brain disorders, such as frontal lobe brain tumor, encephalitis, temporal lobe epilepsy, stroke, significant head trauma, dementia, untreated post-traumatic stress disorder and drug use alcohol or cannabis can also lead to changes in behavior and a period of confusion and disorganization that can lead to acts of violence, underlines the DD Borduas-Page.
” When [des gestes d’une grande violence] occur in a blue sky, for example, in someone who has no history of violence, who was functioning quite well and who [ces gestes] appear quite unexpectedly at a less typical age—psychotic at 50 is a bit late—we consider [des troubles plus organiques] than schizophrenia,” she notes.
This could apply to the case of Pierre Ny St-Amand, aged 51, who, driving a bus, crashed into a daycare center in Sainte-Rose and then entered the establishment where he completely naked screaming.
Autoimmune encephalitis is a pathology that can induce a psychiatric syndrome, reports the Dr of Villers-Sidani, while advancing the hypothesis that Mr. St-Amand could have been affected by such an affection during his crime.
Encephalitis is an inflammation of the brain that can be caused by a virus or by an autoimmune reaction. “Classically, a person who has viral encephalitis has a headache, fever, lethargy and fatigue. In more serious cases, there may be focal neurological signs: paralysis, epileptic seizure, convulsion, the person may be confused, agitated. But in general, the person is in too bad shape to continue to function, like driving a bus, ”describes the neurologist.
Autoimmune encephalitis is a very localized inflammation of the brain caused by antibodies produced by the body. “A cancer in another part of the body can trigger an autoimmune reaction that induces the production of antibodies that will target specific regions of the brain. Antibodies are often seen attacking or irritating the frontal lobes and the limbic system, which is the seat of emotions. This irritation can increase the impulses, disrupt them or make them inappropriate. This can lead to erratic or even violent behavior,” says the specialist.
Often the cancer may be very small and cause no other problems elsewhere. The first manifestation is then a psychiatric syndrome: the person is not himself. His personality has changed, his behavior can be unpredictable.
This irritation of the frontal and temporal lobes can also create small epileptic foci. Convulsions, epileptic seizures can therefore also be a warning sign. However, temporal epilepsy, ie in the limbic system, which is very connected with the frontal lobe, can induce a psychosis which can last several days, several weeks.
Antibodies interfere with brain function, but don’t necessarily cause very clear damage, Dr.r of Villers-Sidani. Nothing abnormal appears on magnetic resonance, except perhaps for small signs of inflammation. “To establish the diagnosis, we can take blood tests to detect the presence of certain antibodies that target the brain, and we must do further imaging of the whole body to find the sign of a small cancer. which would be hidden somewhere and which would have generated this auto-immune reaction. It can sometimes take several weeks before being sure of the diagnosis. »
In general, the best treatment is to remove the cancer that stimulates the production of antibodies. If it is not found, then immunomodulation must be done to help the person return to normal.
Frontotemporal dementias also lead to a change in personality that can lead to unpredictable behaviors due to a degeneration of certain circuits in the frontal and temporal lobes. “But this change is more gradual. Suddenly going from a normal to an erratic state, as seems to have happened for Mr. St-Amand, could have been caused by toxic psychosis or by a more pathological process such as autoimmune encephalitis, ”says the Dr of Villers-Sidani.