Contemporary understanding of brain and behavior is providing new insights, explanations, and treatments for brain disorders. Neurologists, who treat organic disorders, and psychiatrists, who treat behavioral disorders, are forging a unified understanding of mind and brain: neuropsychoanalysis.

16-1 Multidisciplinary Research on Brain and Behavioral Disorders

Most behavioral disorders have multiple causes—genetic, epigenetic, biochemical, anatomical, social–environmental variables—all of them interacting. Research methods directed toward these causes include family studies designed to find a genetic abnormality that might be corrected, biochemical anomalies that might be reversed by drug or hormone therapy, anatomical pathologies that might account for behavioral changes, and social–environmental variables.

Investigators rely increasingly on neuroimaging (fMRI, PET, TMS, ERP) to examine brain–behavior relations in vivo in healthy participants as well as in people with disorders. Interest in more refined behavioral measurements is growing, especially for cognitive behavior, the better to understand behavioral symptoms.

16-2 Classifying and Treating Brain and Behavioral Disorders

Disorders can be classified according to presumed etiology (cause), symptomatology, or pathology. The classification systems developed by psychologists, psychiatrists, and neurologists overlap, and each is revised from time to time. Clearly, better understanding the causes of disorders will lead to better classification systems. Advances in genetics and brain imaging will aid this effort. The table summarizes the range of available treatments, from highly invasive neurosurgery to noninvasive electrophysiology, from moderately invasive pharmacology to behavioral treatments.

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16-3 Understanding and Treating Neurological Disorders

If a disorder, such as depression, is presumably caused primarily by a biochemical imbalance, treatment is likely to be pharmacological, although brain activation with TMS also is effective and is noninvasive. If the disorder has a suspected anatomical cause, treatment may include removal of pathological tissue (as in epilepsy) or implanted electrodes to activate underactive regions (as in Parkinson disease and stroke). Many disorders require medical treatment concurrent with behavioral therapy, including physiotherapy or cognitive rehabilitation in patients with stroke and TBI, and cognitive-behavioral therapies for patients with depression and anxiety disorders.

16-4 Understanding and Treating Behavioral Disorders

The number of people who endure hidden diseases of behavior, especially neurodegenerative disorders and stroke, is increasing as the population of the developed world ages. Like other plagues in human history, dementias affect not only the person with the disease but also the caregivers, about half of whom seek psychiatric care themselves.

16-5 Is Misbehavior Always Bad?

In rare cases, people with a behavioral disorder also have some benefit. An individual who has a brain injury, for example, may suddenly display an artistic talent. The explanation for this acquired savant syndrome is that depressing the brain’s inhibitory systems can activate new skill strategies. Artificially manipulating the brain with cognitive enhancers is a controversial approach to improving brain function.