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pain, or improve performance, the extent of misuse is unclear. “It is hard to know whether entertainers have more substance abuse than others,” says Lieberman, “but the fact that their overdoses and partying make headlines gives us the impression that they do.” (Witness the very public meltdowns of stars like Britney Spears and tragic deaths of singers Amy Winehouse and Prince.)

There is limited evidence that athletes are more prone to substance problems than the general population, and several studies suggest that celebrities in general are at increased risk of addiction. One analysis of drugrelated deaths among famous people found more than half involved entertainers, with athletes the next best represented.

Performance and the Brain

From a neurobiological perspective, the performer’s life is a study in stress. “Our current stress system developed 10-20,000 years ago. It evolved to escape the Smilodon (extinct saber-tooth cat), not to worry about how we would look in front of 40 million people,” says Gerard Sanacora, professor of psychiatry and director of the Yale Depression Program. “An athlete [or other performer] isn’t going to die from putting in a poor performance and getting booed, but the brain perceives it as a threat.”

The dual nature of stress is on full display. “There’s a spectrum from adaptive to toxic, but it’s all the same system,” he says. “When appropriate to changes in the environment, the stress response is positive; it increases cognitive functioning and carries over into enhanced psychomotor, physical activities.” Musicians and athletes know that enhanced arousal is a vital ingredient for vigorous, skilled performance.

“But past that, the downside of the curve becomes evident,” he says. Neuroplasticity—the ability of nerve cells to form and change connections—increases in some areas and declines in others. Reduced growth factor in hippocampal and cortical regions may inhibit working memory. The release of the excitatory neurotransmitter glutamate is critical to how the brain adapts, but at high levels can have a detrimental effect.

“With too great intensity, or prolonged intensity over time, [stress] can contribute to pathophysiologic changes in brain processing, even to the development of the behaviors and emotions we call depression,” Sanacora says. A number of alterations typical in the depressed brain—e.g., reduced hippocampal and prefrontal cortex volume and synaptic density, increase in inflammatory markers—can be related to the effects of chronic stress.

On the immediate level, stress can invade performance, posing physical risks: A 2021 meta-analysis of 18 papers suggested that stress—both surrounding competition and in other aspects of their lives—along with anxiety and, to a lesser extent, depression, increased the risk of injury to athletes including football players, gymnasts, runners, soccer players, and swimmers.

The effect on performance quality is more evasive: studies of its association with anxiety, for example, are inconsistent. “Athletes talk about their optimal zone of functioning; chronic stress makes it hard to get there, which can undermine their confidence,” says Edwards.

For musicians, “the most distressing effect of anxiety is a loss of accuracy—intonation, rhythm, quality of sound,” says Kageyama. “Not as noticeable to an audience as to the performer himself is a tendency to play much more cautiously—not taking risks. Instead of going for highclimax moments, everything is a little more muted; there’s a drastic difference in expressiveness.”

What happens in the performer’s brain, and how stress and anxiety might disrupt it, are far from clear. But it is evident that the skilled movements of sport and artistic performance demand an intricate choreography of events connecting diverse brain regions.

Kathleen Cullen, whose research has focused on “how we move through the world in the face of gravity,” says that in executing complex actions while maintaining balance—as demanded by sports such as gymnastics and basketball and artistic pursuits such as dance—“the brain is computing the sensory input it expects and then comparing it with the sensory feedback it actually receives, combining information from multiple systems.”

The vestibular system [a kind of gyroscope/ accelerometer based on signals from the inner ear] “tells with great precision how the head is moving through space. The proprioceptive system [which tallies input from muscles throughout the body] tells you how limbs are positioned, relative to the body,” says Cullen, professor of biomedical engineering, neuroscience, and otolaryngology at Johns Hopkins University,

These signals come through the spinal cord and converge in the cerebellum, “where the brain computes its prediction based on an internal model of sensory flow…. when there’s a difference between proprioceptive and vestibular input and what the brain expects, there’s an error signal, which the athlete can then correct on the fly.” The cerebellum also receives signals from the ventral striatum, bringing in higher-level cognitive functions. All this happens within milliseconds, she says.

More generally, the brain’s comparison of an internal model deeply entrenched by the motor learning of endless practice, and the sensory input of the act itself, underlies highly skilled performance. To pitch a cut fastball in baseball with pinpoint precision or execute flawless vibrato on the violin, “you certainly need an intimate relationship in terms of movement and expected feedback,” she says.

How things go wrong is an ongoing area of research, Cullen says. But given the complex orchestration of brain processes, it’s no small surprise that overarousal creates