The Secret Life of the Brain (3 of 5) The Teenage Brain (2002)

Summary

The adolescent brain is still developing

By the teenage years, the brain has reached roughly adult size, but it is not fully mature. Adolescence is a period of substantial change, especially in the prefrontal cortex.

The prefrontal cortex supports planning, reasoning, judgment, self-control, and responsibility. Because these abilities are still developing, teenagers may experience emotional turmoil and have difficulty weighing consequences.

The program describes the adolescent brain as adaptable: connections between neurons strengthen or are pruned according to experience. In this sense, the brain adapts to its environment and to the activities a young person repeatedly engages in.

Schizophrenia may emerge during this period of change

The program follows Courtney Hale Cook, who developed schizophrenia near the end of high school. His experience illustrates how the illness can disrupt thinking, perception, emotion, motivation, and a person’s sense of self.

Schizophrenia can involve hallucinations and unusual perceptions, as well as “negative” symptoms such as apathy, diminished emotional expression, and difficulty feeling pleasure. It can impair concentration and reasoning. The program also describes the distress associated with the illness and the risk of suicide.

Brain scans have not revealed a single obvious lesion that identifies schizophrenia. Instead, researchers have found that several regions involved in thought, memory, and emotion may function poorly. The program presents the prefrontal cortex as a possible coordinator of these systems: when it is not working well, mental activity may become disorganized.

Imaging studies described in the program found slightly enlarged brain ventricles in some people with schizophrenia, alongside slight thinning of the cortex. These are presented as subtle differences, not definitive diagnostic markers.

One developmental theory is that problems originating earlier in brain development remain hidden until adolescence, when the prefrontal cortex undergoes further maturation. The program mentions possible genetic, nutritional, or infectious influences but emphasizes that the causes remain uncertain.

Elaine Walker’s examination of childhood home movies found unusual motor patterns more often among children who later developed schizophrenia. These movements also occur in children who do not develop the illness, so the observations cannot predict who will become ill.

How schizophrenia research and treatment are portrayed

Researchers use tasks that test attention and reasoning, as well as brain-imaging experiments that record responses to emotional pictures.

The program explains hallucinations as experiences generated by a misfiring brain. People do not simply “hear with their ears” or “see with their eyes”: the brain interprets incoming signals and can sometimes generate perceptions without an external source.

It presents dopamine as one possible part of the mechanism behind psychosis. Antipsychotic medications can reduce dopamine’s effects and relieve symptoms, though they do not cure schizophrenia.

The cases illustrate that treatment response differs. Medication greatly helped Isaac Wallace, while Sabrina continued to experience serious symptoms despite several attempted medicines. Courtney’s treatment helped him move beyond suicidal thoughts and continue his education.

Addiction can hijack the brain’s reward system

The program portrays adolescence as a particularly risky time to experiment with drugs and alcohol because independence is increasing while judgment and self-control are still developing.

Addictive substances alter neurotransmitter activity in the brain’s reward pathway. The program describes many drugs as chemical “mimics” that disrupt the brain’s usual signaling.

Cocaine, for example, blocks dopamine transporters, causing dopamine to build up in the synapse and producing an intense high. With repeated use, the brain adapts by reducing dopamine receptors. This can weaken the drug’s effect while also making ordinary rewards—such as food, exercise, or relationships—feel less pleasurable.

The result can be a cycle in which a person increasingly takes the drug not to feel especially good, but to escape feeling bad. Jesse Gatar’s account illustrates how use can progress from experimentation to dependence and take over daily life.

Alcohol affects people differently. In a study described by Mark Schuckit, volunteers received equivalent amounts of alcohol while researchers recorded their brain waves and asked how intoxicated they felt. One participant showed a lower response and felt less affected. The program suggests that people who feel less effect may be more likely to keep drinking, increasing their exposure and risk. A low response and a family history of alcoholism are described as risk factors, not guarantees.

Craving, recovery, and relapse

Anna Rose Childress’s research examined whether drug-related cues could activate craving in people recovering from cocaine addiction. After participants had been drug-free for two weeks, researchers showed them nature scenes and drug-use videos during brain scans.

The drug-related videos produced stronger brain activity than the nature scenes. The program presents this as evidence that cues associated with drug use can trigger intense craving, even after a period without drugs.

Edward Coleman reported that baclofen, a muscle relaxant he took for another condition, seemed to reduce his cocaine cravings. A PET scan showed little difference in his brain response to nature and cocaine videos while he was taking it. The program presents this as a promising observation under early investigation, not an established treatment.

The program says relapse is common after rehabilitation and describes a ropes-course exercise at a treatment center as a symbol of recovery. Participants practice facing fear and relying on one another. The broader lesson is that recovery involves recognizing automatic drug-seeking responses and drawing on other capacities, especially the prefrontal cortex’s executive functions and self-control.

Central lesson

Adolescence is a period of major brain development that can bring both opportunity and vulnerability. The still-maturing brain helps explain why judgment and self-control may be difficult, while developmental changes may coincide with the emergence of serious conditions such as schizophrenia. Drugs can alter reward and decision-making systems, but the program also emphasizes treatment, research, support, and the possibility of rebuilding a life after illness or addiction.

Speakers and sources identifiable in the subtitles

• Narrator and unnamed expert voices — Provide explanations of adolescent brain development, schizophrenia, dopamine, addiction, and treatment. Most experts are not named in the captions.
• Courtney Hale Cook — Describes his experience with schizophrenia.
• Courtney’s mother — Recounts changes in his behavior and perceptions.
• Elaine Walker — Psychologist discussing childhood motor development in home movies.
• Sabrina — A young person describing her experience of schizophrenia and hallucinations; her surname is unclear in the auto-generated captions.
• Sabrina’s mother — Describes Sabrina’s symptoms and treatment.
• Isaac Wallace — Describes hearing voices and the effects of treatment.
• Isaac’s mother — Discusses his recovery.
• Jesse Gatar — Describes teenage drug use, cocaine addiction, and rehabilitation.
• Mark Schuckit — Discusses research on individual differences in response to alcohol.
• Justin and Elica — Volunteers in the alcohol-response study; Elica’s name may be misrendered in the captions.
• Edward Coleman — Describes his addiction, recovery, and experience with baclofen.
• Anna Rose Childress — Discusses brain-imaging research on craving and drug-related cues.
• Researchers and staff at the University of Iowa, the University of North Carolina, the San Diego Veterans Hospital, and the Caron Foundation — Appear in connection with the studies and rehabilitation program.
• Opening poem — Quoted at the start; its author is not identified in the subtitles.
• End-credit funders named in the video — The National Science Foundation, Pfizer, the Medtronic Foundation, the Park Foundation, the Dana Foundation, the Corporation for Public Broadcasting, and PBS viewers.