The author believes that people have come to accept a toxic society as normal. A culture they do not question or notice is harming them both mentally and physically—two types of harm that are profoundly connected and which must be healed together. Trauma, which most people regard as the result of catastrophic events, is a universal experience, which affects not only individuals but families, races, and nations. Dealing effectively with the emotions it arouses is vital to human well-being. Relationships with other people are also a critical factor in determining both physical and mental health.

Maté cites evidence from the field of epigenetics indicating that one’s environment may have an effect on one’s genes without producing any chemical alteration. He examines the recent increase in autoimmune diseases, for which there is no generally accepted explanation, to produce a hypothesis that disease may be a changing process rather than a fixed entity. This process is linked to trauma and to the suppression of one’s authentic self in childhood, a suppression that is often necessary to gain the acceptance and approval of adults. However, once this suppression is understood, it can be corrected later in life.

“Human nature,” Maté points out, is a term normally used in a negative context. He disputes the idea that people are naturally aggressive and selfish, saying that these attributes are the product of a toxic society, whereas it is natural for humans to need connections with those around them. Children are profoundly influenced by their connection to parents and other caregivers, and studies have shown that those who receive more affection in their early years experience less anxiety and distress later in life. A child’s health is also profoundly affected on a physical level by the stress the mother experiences before and during childbirth.

Parents naturally know how to raise their children, but a toxic culture makes them forget. This is when they rely on the plethora of advice available, most of which tells them to put their own desires and the dictates of society before the needs of the child. When the bond between adult and child is severed, children seek approval from their peers and immerse themselves in a corporate digital culture which inculcates inhumane, materialistic values. Children are conditioned to fulfill the needs of society, abandoning their individuality for an inauthentic “social character” based on conformity and consumerism.

Addiction, which has historically been misunderstood as the result of the addict’s bad choices or as a disease, is really a way of coping with suffering. Doctors who treat addicts should ask what benefit the drug, alcohol, or other substance or behavior confers on the addict and what type of suffering is being palliated. Instead, both doctor and patient are often all too willing to treat addiction and other mental problems from a purely biological standpoint, since this means that they do not have to do the hard work of examining the trauma in the patient’s life. People are so unwilling to face these traumas that their mind often concocts alternative narratives to explain the emotional scars they bear. These stories people tell themselves serve a purpose at the time but are often damaging in the long run.

The author discusses the connection between capitalism and illness, both mental and physical. Capitalist societies create stress and insecurity for all but the wealthy, and they also encourage people to value material possessions more than human connections. This has led to unprecedented levels of alienation and loneliness in modern developed nations. Such societies also allow corporations to prey on vulnerable people, hijacking their brains through neuromarketing and...