A change in personality can be a warning that something is not right. What could be going on?

Illnesses affect emotions; pain can make us more irritable or intolerant; a disability can lead to depression. But the picture is different when we are faced with an illness that leads to a change in personality or behaviour.

Personality is something stable, as individual as the color of our eyes, and it largely defines our behavior and decisions. When there is a marked variation in these traits, whether abrupt or gradual, there is possibly a compromise in brain function and, therefore, rapid measures must be taken to avoid or mitigate damage that could be serious.

Changes in personality, thinking, or behavior may be caused by:

• Mental illness: bipolar disorder, schizophrenia, post-traumatic stress, among other pathologies.
• Substances: alcohol, drugs or as a side effect of some medications.
• Poisoning: as is the case of saturnism, which occurred in ancient Rome, due to chronic lead poisoning, when kitchen utensils were made of this material.
• Traumas, brain diseases or systemic disorders.

Straight to the brain

There are diseases with a rapid onset, meaning that the symptoms, structural and personality changes appear from one moment to the next. They can occur due to:

• Head trauma: such as concussion, especially involving the frontal lobes, and post-concussion syndrome. Caution must be exercised with any blow because damage may not occur immediately but may take days or weeks.
• Strokes: Cerebral ischemia secondary to thrombosis, embolism, or intracerebral hemorrhage. As with trauma, it is important to act quickly and perform appropriate tests to determine which areas of the brain have been affected and to be able to intervene or prevent the damage.
• Brain infections: meningitis, encephalitis, and the human immunodeficiency virus (HIV), which affects the brain.
• Brain tumors: those that, if they are found in the areas that compromise personality, will affect it.

There are also diseases in which structural changes and the appearance of symptoms are more progressive:

• Dementia: In particular, behavioral variant frontotemporal dementia in which the person may become more cognitively rigid, compulsive, have language problems, changes in habits, heteroaggression, with memory problems, praxis and loss in executive capacity.
• Multiple sclerosis: because it affects any part of the central nervous system. In its advanced state, it may cause euphoria or crying fits for no apparent reason.

There are three special cases that are important to mention:

• Parkinson's disease: The person enjoys a normal state of consciousness, but his motor ability (motor symptoms) is impaired after several years of emotional (non-motor) symptoms. This causes his emotional states to deteriorate. Depression often appears, even before the rigidity or tremor. It should be noted that there are no changes in personality, but in mood states.
• Epilepsy: If a child has congenital epilepsy, these changes will not be seen. However, if a person develops epilepsy in adolescence or adulthood, certain changes can be determined: impulsivity, poor interpersonal relationships, obsessiveness, fixed interests (philosophical and religious), greater reactivity, difficulty adhering to changes, being more fearful, isolated.
• Episodes of delirium in older people: Previously known as Organic Mental Syndrome, it occurs after an infection, illness or decompensation, or when there are metabolic imbalances such as electrolyte disturbances. It is characterized by changes in the sleep-wake cycles, hallucinations and changes in behavior. However, they improve when the underlying illness or imbalance is corrected. They are variations in behavior and mood, but not in personality. There are refractory delusions that do not improve and are related to much more serious conditions.

Signs that something is wrong

If any of these changes are detected in a person, you should be alert:

• Symptoms of sudden onset.
• Attempts to harm oneself or others.
• Fever.
• Headache
• Difficulty walking, maintaining balance, or speaking.
• Mouth twisting or facial paralysis.
• Mental confusion: It is an alteration in consciousness that causes the sufferer to not know where they are, to be unable to adapt to their environment, to be unable to respond coherently and appropriately to a situation and, in some cases, to not even be able to give their name or current status and situation.
• Delirium: They are fixed false beliefs, despite evidence against those beliefs, as a misinterpretation of real perceptions and experiences.
• Disorganized speech or behavior: They are identified because words or behaviors do not contain the expected logical connections between thoughts, situations, or between questions and answers. Topics and reactions may be completely unconnected.
• Hallucinations: It consists of seeing, hearing, smelling, tasting or feeling things that are not there, that is, perceiving stimuli that are not really produced by something external.
• Extreme moods: There are personalities that react in extreme ways by nature. But, in a person who has been generally balanced, sudden outbursts of anger, extreme euphoria or deep depression should be assumed as warning signs.
• Strange behaviors in the person: great extroversion in people who have been shy or isolation in extroverted people. Sudden anger in someone with a calm temperament or apathy in someone who has been reactive by nature.

Does microbiota affect personality?

Three large and different families, millions of bacteria, live in the gastrointestinal tract. This is what is known as the microbiota. Apart from playing a fundamental role in the way we digest food and in keeping “bad” bacteria that can affect the body at bay, it is now known that they can influence psychiatric conditions such as anxiety or depression.

Strange? Not so much. At the embryonic level, the brain and the gut have the same origin, and in fact, the digestive system is one of the largest producers of neurotransmitters – such as serotonin, the precursor of dopamine, the pleasure hormone – and hormones. That is why it is called the “second brain”.

This does not mean that probiotics can replace therapy, but they can improve the absorption of medications and have a positive effect on mood and the general condition of the person.

The structure of personality

It is formed towards the anterior part of the brain, between the amygdala and the stratumfrontal system, that is, from the striatum towards the frontal lobe, with the intervention of several basal ganglia or nuclei.

Roughly:

• The brain amygdala It performs vital actions for the processing and storage of emotional reactions, for emotional learning, the reward system and is related to addictions. It is also responsible for modulating memory and allows the development of social cognition.
• The putamen It is related to the development of feelings, specifically love and hate.
• The pale globe transmits information to the thalamus.
• The accumbens performs activities related to emotional processes and the elaboration of feelings, especially pleasure, reward, fear, aggression or addiction.

Behavioural, cognitive or behavioural changes in older people are never normal; they may be a sign of a stroke, ischemia or a tumour.

Care should be taken with older people after a fall; there may be bleeding secondary to the trauma which, although not noticeable initially, may become apparent days or weeks later.

The content is part of the magazine 5 Sentidos and was created by: Alejandro Villarraga Peña; MD neurologist, and Sandro Gómez Maquet; MD nutritionist.