Legal arguments, in criminal trials, the sentencing phase of capital trials, or in post-conviction proceedings in American courts, may incorporate family history, environment, and other presumed nonculpable influences on the development and predispositions of defendants. Attorneys may also proffer expert testimony to enhance a defense claim that the defendant was less culpable for the behavior charged; for example, inherited traits. The terms heredity and genetics, however, have various meanings and implications for responsibility. This report tracks arguments and testimony cited in American appellate cases in which genetics appeared within mitigation arguments or claims of ineffective assistance of counsel. The results indicate general lack of scientific detail from expert witnesses and poor results in achieving habeas corpus hearings or new trials. Difficulties included demonstrating a scientific basis for genetics claims, separating biological from family/environmental factors, the high threshold for habeas corpus and ineffective assistance of counsel certification, and the group-to-individual inferences drawn from research. The article concludes with two suggestions for expert witnesses: 1) that mere inclusion of hereditary or genetic influences tends to be insufficient to reduce criminal culpability and 2) that invoking genetics or heredity is more effective when bundled with mitigating factors describing the defendant’s life experiences.

The use of varenicline as an aid to smoking cessation is ordinarily safe and effective. Its mechanism of action includes blockade and partial agonism of central nicotine receptors, thus relieving the user of nicotine withdrawal while providing release of dopamine in the nucleus accumbens. A small fraction of users develop neuropsychiatric effects, which can include changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic, as well as suicidal ideation, suicide attempt, and completed suicide. When the toxicity includes aggression toward others or dangerous acts that run afoul of the law, the patient may have a defense of involuntary (pathological) intoxication. This article reviews reported cases and scenarios that have utilized a causal relationship between use of varenicline and otherwise unaccountable behaviors. Unlike voluntary intoxication, involuntary intoxication can be used as a defense against criminal charges. The criminal defendant must prove that the drug was used for ordinary medical reasons (not to become intoxicated), that there was a causal relationship between ingestion of the drug and the behavioral effect, and that, at the time of the criminal act, the defendant did not know that his/her actions were wrong. In essence, it is an insanity defense without risk of subsequent civil commitment. Since some physicians and patients with existing mental disorders are afraid of behavioral effects of varenicline, there could be a chilling effect on prescribing. Ethical concerns are addressed.