Kaplan + Sadock's Synopsis of Psychiatry, 11e

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Chapter 31: Child Psychiatry

Rostral

Caudal

Somites

Neural crest

Neural tube

Neural groove

Neural fold

Neural tube

Neural plate

Mesoderm

Ectoderm

(a)

(b)

(c)

(d)

Endoderm

Figure 31.1-2 Formation of the neural tube and neural crest. These schematic illustrations follow the early development of the nervous system in the embryo. The drawings above are dorsal views of the embryo; those below are cross sections. A. The primitive embryonic central nervous system (CNS) begins as a thin sheet of ectoderm. B. The first important step in the development of the nervous system is the formation of the neural groove. C. The walls of the groove, called neural folds, come together and fuse, forming the neural tube. D. The bits of neural ecto- derm that are pinched off when the tube rolls up are called the neural crest, from which the peripheral nervous system (PNS) will develop. The somites are mesoderm that will give rise to much of the skeletal system and the muscles. (Reprinted from Bear MF, Conners BW, Paradiso MA, eds. Neuroscience: Exploring the Brain . 2 nd ed. Philadelphia: Lippincott Williams & Wilkins. 2001:179, with permission.)

Genetic Disorders In many cases, genetic counseling depends on prenatal diag- nosis. The diagnostic techniques used include amniocentesis (transabdominal aspiration of fluid from the amniotic sac), ultrasound examinations, x-ray studies, fetoscopy (direct visu- alization of the fetus), fetal blood and skin sampling, chorionic villus sampling, and a -fetoprotein screening. In about 2 percent of women tested, the results are positive for some abnormal- ity, including X-linked disorders, neural tube defects (detected by high levels of a -fetoprotein), chromosomal disorders (e.g., trisomy 21), and various inborn errors of metabolism (e.g., Tay- Sachs disease and lipoidoses). Figure 31.1-3 illustrates hyper- telorism of the eyes. Some diagnostic tests carry a risk; for instance, about 5 per- cent of women who undergo fetoscopy miscarry. Amniocente- sis, which is usually performed between the 14 th and 16 th weeks of pregnancy, causes fetal damage or miscarriage in less than 1 percent of women tested. Fully 98 percent of all prenatal tests in pregnant women reveal no abnormality in the fetus. Prenatal testing is recommended for women older than 35 years of age and for those with a family history of a congenital defect. Parental reactions to birth defects can include feelings of guilt, anxiety, or anger as their worst fears during the pregnancy

are realized. Some degree of depression over the loss of the fantasized perfect child may be observed before the parents develop more active coping strategies. Termination of a preg- nancy because of a known or suspected birth defect is an option chosen by some women. Maternal Drug Use Alcohol.  Alcohol use in pregnancy is a major cause of serious physical and mental birth defects in children. Each year, up to 40,000 babies are born with some degree of alco- hol-related damage. The National Institute on Drug Abuse (NIDA) reports that 19 percent of pregnant women used alcohol during their pregnancy, the highest rate being among white women. Fetal alcohol syndrome (Fig. 31.1-4) affects about one third of all infants born to alcoholic women. The syndrome is charac- terized by growth retardation of prenatal origin (height, weight); minor anomalies, including microphthalmia (small eyeballs), short palpebral fissures, midface hypoplasia (underdevelop- ment), a smooth or short philtrum, and a thin upper lip; and central nervous system (CNS) manifestations, including micro- cephaly (head circumference below the third percentile), a his- tory of delayed development, hyperactivity, attention deficits,