Between 50% and 75% of children with conduct disorder onset before age 10 and callous-unemotional traits develop an adult substance use disorder.
"So of those kids who have conduct disorder, especially before the age of 10 with these callous-unemotional features, we would expect that 50 to 75% of them will have a substance use disorder in adulthood." (said at 0:56:50)
Although childhood conduct disorder and conduct problems are recognized risk factors for later substance use problems, the specific assertion that 50% to 75% of children with early-onset conduct disorder (before age 10) and callous-unemotional (CU) traits develop an adult substance use disorder is an overstatement not supported by the literature. Meta-analyses demonstrate only modest associations (θ ≈ 0.15-0.17) between CU traits and youth substance use, and prospective longitudinal cohorts (such as Fast Track and the Child Development Project) indicate that CU traits generally fail to provide substantial incremental predictive validity for adult substance use disorders once general conduct problems are accounted for.
An autopsy following Charles Whitman's mass shooting at UT Austin found that he had a tumor in his amygdala.
"When after he died, the state of Texas ordered an autopsy, and they found that he had this tumor... He got a tumor in his amygdala, and he wouldn't have done it if he hadn't had this tumor." (said at 1:06:10)
Following the 1966 University of Texas tower shooting, an autopsy and subsequent medical review by the Governor-appointed Connally Commission did find a glioblastoma (astrocytoma) in the temporal lobe compressing the amygdala and adjacent limbic structures. However, asserting that 'he wouldn't have done it if he hadn't had this tumor' is an overstatement. Forensic neuropathologists and historical expert panels concluded that while the tumor may have contributed to his impulse dysregulation and mood changes, definitive causation cannot be established, particularly given other contributing factors including amphetamine abuse, severe emotional stressors, and potential traumatic brain injury.
In animal experiments where rats are shocked while pressing a bar for alcohol, some rats cease pressing the bar while others paradoxically increase their rate of pressing.
"If you give a rat alcohol every time it presses a bar, and then you stop mid-experiment and you start shocking it, some rats will stop pressing the bar, and other rats will actually increase their rate of behavior." (said at 1:46:47)
In rodent operant conditioning models of compulsive alcohol use, introducing footshock punishment reveals a bimodal distribution: punishment-sensitive rats suppress or cease lever pressing, whereas punishment-resistant (compulsive) rats continue to press and seek alcohol despite the shock. However, published literature characterizes this compulsive phenotype as persistent, aversion-resistant responding (resistance to suppression), rather than a paradoxical increase above baseline response rates.
- context: Rodent models for compulsive alcohol intake. (Alcohol (Fayetteville, N.Y.) 2014) · cited 199x in the literature
"Continued seeking and drinking of alcohol despite adverse legal, health, economic, and societal consequences is a central hallmark of human alcohol use disorders. This compulsive drive for alcohol, defined by resistance to adverse and deleterious consequences, represents a major challenge when attempting to treat alcoholism clinically." (abstract, background, passage verified)
pubmedfull study (doi) - context: Evidence for a Long-Lasting Compulsive Alcohol Seeking Phenotype in Rats. (Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 2018) · cited 98x in the literature
"Compulsive alcohol seeking, maintained in the face of the risk of punishment, emerged in only a subset of rats with a predisposition to prefer and drink alcohol, and was maintained for almost a year." (abstract, results, passage verified)
pubmedfull study (doi) - context: Punishment of alcohol-reinforced responding in alcohol preferring P rats reveals a bimodal… (Progress in neuro-psychopharmacology & biological psychiatry 2018) · cited 67x in the literature
"We found evidence for a bimodal distribution in the response to punishment in alcohol preferring P rats. We only observed this population split when rats received constant shock intensity for three sessions, but not when increasing shock intensity was used. This observation provides evidence for the existence of two distinct groups of rats, defined by their response to punishment, in an otherwise homogeneous population." (abstract, results, passage verified)
pubmedfull study (doi)