Unformatted text preview: become far more sophisticated in its interpretation of the genetic code. Imaging the Brain
with the genomic revolution, neuroscientists have dramatically improved their ability to image the living brain noninvasively. There are three major types of neuroimaging studies. The first is morphometric analysis, which
MOVING IN PARALLEL 100 SCIENTIFIC AMERICAN SEPTEMBER 2003 COPYRIGHT 2003 SCIENTIFIC AMERICAN, INC. TELLTALE SIGNS IN THE BRAIN
THREE-DIMENSIONAL MAPS of the brain derived from magnetic resonance imaging reveal that one type of schizophrenia causes a characteristic pattern of tissue loss in the cerebral cortex. The maps show that the average annual reduction in the cortical gray matter of adolescent patients suffering from childhood-onset schizophrenia (right) is much greater than the loss in healthy teenagers (left) between the ages of 13 and 18. Average Annual Loss (percent) 0 NORMAL ADOLESCENTS 1 2 3 4 5 SCHIZOPHRENIC SUBJECTS COURTESY OF PAUL THOMPSON AND ARTHUR W. TOGA UCLA Laboratory of Neuro Imaging AND JUDITH L. RAPOPORT National Institute of Mental Health www.sciam.com SCIENTIFIC AMERICAN 101 COPYRIGHT 2003 SCIENTIFIC AMERICAN, INC. THE SPECTRUM OF PSYCHIATRIC ILLNESS
MENTAL DISORDERS, which afflict millions of people every year, can be hard to diagnose. As the table shows, some illnesses have overlapping symptoms. Certain mood disorders, such as major depression and dysthymia, have similar symptoms but differ in severity. Among anxiety disorders, the primary distinction is the trigger that initiates fear, panic or avoidance behavior. Psychotic disorders also range from mild to severe. More definitive diagnostic methods are clearly needed. PREVALENCE (PERCENT)*
MOOD DISORDERS Major Depression COMMON SYMPTOMS
Characterized by episodes during which the patient feels sad or empty nearly every day; loses interest or pleasure in hobbies and activities; experiences changes in appetite, weight, energy levels or sleeping patterns; or harbors thoughts of death or suicide Similar to major depression, but the symptoms are less severe and more chronic. Sad or empty mood on most days for at least two years. Other symptoms include low self-esteem, fatigue and poor concentration. Episodes of abnormally elevated or irritable mood during which the patient feels inflated self-esteem; needs less sleep; talks more than usual; or engages excessively in pleasurable but unwise activities. These manic periods may alternate with depressive episodes Depressive episodes alternate with less severe manic periods that do not markedly impair functioning or require hospitalization Excessive or unreasonable fear of a specific object or situation, such as flying, heights, animals, receiving an injection or seeing blood. Exposure to the stimulus may provoke a panic attack (...
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