There isn't a direct gene for ADHD or depression, but there is a 'sensitivity gene' that makes individuals more susceptible to stress. According to epigenetics, present and nurturing parenting in the first year of life can effectively neutralize the expression of this gene, preventing future mental illness.

Brain imaging suggests people with ADHD may have a reward pathway that is less activated by stimuli and contains fewer dopamine receptors at baseline. This inherent "reward deficit" could create a state of craving even before exposure to addictive substances, increasing vulnerability.

People with ADHD don't lack attention; their brain's "salience network" fails to distinguish between important and unimportant stimuli. Every sound or movement is treated as relevant, causing distraction. Neurofeedback can train this network to filter out noise and focus on the primary task.

Dr. Bolsiewicz reframes major depression not as a purely psychological issue, but as a physiological condition rooted in inflammation. He states with "total clarity" that depression, along with neurodegenerative diseases like Alzheimer's and Parkinson's, is a manifestation of chronic inflammation affecting the brain.

A significant number of medications prescribed for mental illness are also used to treat epilepsy. This overlap suggests that mental disorders and seizure conditions share underlying biological mechanisms, opening the door for non-pharmacological epilepsy treatments like the ketogenic diet to be applied to psychiatry.

Early stress over-activates the amygdala (the brain's stress 'on' switch) while stunting the hippocampus (the 'off' switch). This creates a neurological imbalance of 'all gas, no brakes,' resulting in a state of hypervigilance and dysregulation that is often diagnosed as ADHD.

It's a myth that all cells are a 50/50 blend of parental DNA. Neuroscientist Catherine Dulac's work shows that entire brain areas can be genetically identical to either the mother or the father. This explains why certain behaviors and traits are so strongly inherited from one parent.

Your outcomes are influenced not just by your own DNA but by the genes of those in your social environment, a concept called 'genetic nurture.' A spouse’s genes can affect your likelihood of depression, and a child's genes can evoke specific parenting behaviors, showing that the effect of genes doesn't stop at our own skin.

Fears about unintended trade-offs from embryo selection are largely unfounded due to 'positive pleiotropy.' The genes for many diseases are positively correlated. This means selecting against a disease like severe depression often provides a 'free' reduction in the risk of other conditions like bipolar disorder and schizophrenia.