What are some current medical explanations of criminal behavior?

A major medical explanation for criminal behavior is antisocial personality disorder, more commonly known as psychopathy or sociopathy (though these are no longer medically the best terms). Antisocial personality disorder consists of a strong reward drive without the ability for empathy. People suffering from this disorder tend to be manipulative, abusive, unstable, and often charming in the single-minded pursuit of their goals. It is also extremely common for these people to be criminals. The ability to cause pain and distress without feeling guilt or remorse for their actions makes people with this disorder naturally primed for crime. Notions of right and wrong and regard for the law do not pose the same stopping forces for those with anti-social personality disorder as they would with the average person. Based on estimates of the number of individuals with anti-social personality disorder in the general population and in prisons, it is believed that over 90% of adult men with this disorder are currently in prison (or on parole or probation following criminal charges).
Other mental illnesses that strongly affect a person’s ability to empathize or maintain a stable hold on reality, such as schizophrenia, can lead to criminal behavior. These types of illness can induce hallucinations or delusions that may push the sufferers to criminal acts like murder, theft, or assault, for example.
Another point on this topic is the fact that suicide is considered a criminal act. Depression is the strongest and most common cause of suicidal thoughts and completion.
It should be noted that not all criminals are mentally ill, and not all mentally ill people are criminals; this answer only aims to discuss the ways that mental illnesses may leave people vulnerable to criminal charges or infractions of the law.
It is also important to note on this topic that suffering from a mental illness (with the exception of antisocial personality disorder) often means that someone is more likely to be the victim of crime (rather than the perpetrator), and mentally ill individuals in general should not be automatically profiled as criminals.
https://www.mayoclinic.org/diseases-conditions/antisocial-personality-disorder/symptoms-causes/syc-20353928

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4059069/

https://www.psychologytoday.com/us/blog/happiness-in-world/201004/the-six-reasons-people-attempt-suicide