Psychiatric Mental Health Nursing by Videbeck

Although much remains unknown about what causes
mental illness, science in the past 20 years has made
great strides in helping us understand how the brain
works and in presenting possible causes of why some
brains work differently than others. Such advances
in neurobiologic research are continually expanding
the knowledge base in the field of psychiatry and are
greatly influencing clinical practice. The psychiatric-
mental health nurse must have a basic understand-
ing of how the brain functions and of the current
theories regarding mental illness. This chapter in-
cludes an overview of the major anatomic structures
of the nervous system and how they work—the neuro-
transmission process. It presents the major current
neurobiologic theories regarding what causes mental
illness including genetics and heredity, stress and the
immune system, and infectious causes.
The use of medications to treat mental illness
(psychopharmacology) has evolved from these
neurobiologic discoveries. These medications directly
affect the central nervous system (CNS) and, sub-
sequently, behavior, perceptions, thinking, and emo-
tions. This chapter discusses five categories of drugs
used to treat mental illness including mechanisms of
action, side effects, and the roles of the nurse in ad-
ministration and client teaching. Although pharma-
cologic interventions are the most effective treatment
for many psychiatric disorders, adjunctive therapies
such as cognitive and behavioral therapy, family ther-
apy, and psychotherapy greatly enhance the success
of treatment and the client’s outcome. Chapter 3 dis-
cusses these psychosocial modalities.

THE NERVOUS SYSTEM

AND HOW IT WORKS

Central Nervous System

The CNS is composed of the brain, the spinal cord,

and associated nerves that control voluntary acts.

Structurally the brain is divided into the cerebrum,

cerebellum, brain stem, and limbic system (Lewis,

2000). Figures 2-1 and 2-2 show the locations of these

structures.

CEREBRUM

The cerebrum is divided into two hemispheres: all

lobes and structures are found in both halves of the

brain except for the pineal body or gland which is

located between the hemispheres. The pineal body is

an endocrine gland that influences the activities of

the pituitary gland, islets of Langerhans, parathy-

roids, adrenals, and gonads. The corpus callosum is

a pathway connecting the two hemispheres and co-

ordinating their function. The left hemisphere con-

trols the right side of the body and is the center for

logical reasoning and analytic functions such as

reading, writing, and mathematical tasks. The right

hemisphere controls the left side of the body and is

the center for creative thinking, intuition, and artis-

tic abilities.

The cerebral hemispheres are each divided into

four lobes: frontal, parietal, temporal, and occipital.

Some functions of the lobes are distinct; others are

integrated. The frontal lobes control the organiza-

20 Unit 1 CURRENTTHEORIES ANDPRACTICE

Parietal lobe

Occipital lobe

Cerebellem

Pons

Medulla

Frontal lobe

Temporal lobe

Figure 2-1.Anatomy of the brain.