Abnormal Psychology

Understanding Psychological Disorders: The Neuropsychosocial Approach 67

Moreover, studies of rats have also demonstrated the infl uence of social factors.

For example, in one study, rats received inescapable shocks either alone or in pairs.

The pairs of rats fought when shocked. But these rats, when tested individually

2 days later, were less likely to show learned helplessness than the rats that were orig-

inally shocked alone (Zhukov & Vinogradova, 1998). Perhaps the fi ghting helped

to distract the paired rats from the shocks, or perhaps the neural events that pro-

voked the rats to fi ght also protected them from subsequent learned helplessness.

What does this have to do with humans? Consider the fact that social factors

can create an aversive situation from which an individual cannot escape, such as

abuse (physical, sexual, or emotional), social discrimination, or poverty (for Anna,

in Case 2.1). Characteristics of the environment, such as uncontrollable noise and

crowding, are associated with a learned helplessness response (Evans & Stecker,

2004). These events lead to changes in psychological factors, such as the individual’s

beliefs (“I can’t escape, so I might as well give up”), goals (“No matter what I do it

doesn’t help, so I must simply endure it”), and behavior (staying put). Inturn, these

events lead to neurological changes, such as a reduced serotonin level in the brain,

which is associated with depression. And we’ve already seen how learned helpless-

ness may contribute to some cases of depression.

Let’s conclude this chapter by briefly examining how neurological, psychologi-

cal, and social factors might have affected each other via feedback loops in the case of

Big Edie and Little Edie. Both women were artistic, unconventional, and independent

(psychological factor), but their social class and the time in which they lived made their

behavior “inappropriate,” leading them to be discriminated against within their extended

family and community (social factor). In turn, the social constraints of their day prevented

them from having jobs or careers, and so they were unable to support themselves; they

were fi nancially dependent on others (social), which created its own stress (neurological

and psychological). These external realities, in turn, may have heightened their feeling

that people were out to get them (psychological factor). Moreover, it is possible that they

had neurological characteristics—such as emotional reactivity—that predisposed them

to behave in certain ways, which in turn evoked certain responses from others.

We will draw on the neuropsychosocial approach—considering all three types

of factors and their feedback loops—to understand the various psychological dis-

orders discussed in this book. Neurological factors (genetics, brain structure and

function, and bodily responses), psychological factors (learning and behavior,

mental processes and mental contents, and emotions), social factors (social stres-

sors, relationships, family, culture, and socioeconomic status), and the interactions

among these factors all play a role in explaining psychological disorders.

Summary of Neurological

Factors

The nervous system has two major parts: the

central nervous system (CNS), which is com-

posed of the brain and spinal cord, and the

peripheral nervous system (PNS), which is

composed of the sensory-somatic nervous sys-

tem and the autonomic nervous system (ANS).

The ANS controls many involuntary func-

tions, such as those of the heart, blood ves-

sels, and digestive tract. The ANS has two

major components: (1) The sympathetic ner-

vous system produces more adaptive bodily

functioning in an emergency with the fight-

or-flight response. As part of this response,

the hypothalamic-pituitary-adrenal axis (HPA

axis) manages the production of cortisol,

which helps the muscles prepare for physi-

cal exertion. The HPA axis and high levels of

cortisol are involved in depression and stress-

related psychological disorders. (2) The para-

sympathetic nervous system typically brings

the body back to its normal state after a fi ght-

or-fl ight response.

The brain is divided into two hemispheres,

which each have four major lobes: occipital

lobe, parietal lobe, temporal lobe, and frontal

lobe. Subcortical (beneath the cortex) areas

of importance are as follows: (1) the limbic

system, which includes the hypothalamus,

the amygdala, and the hippocampus; (2) the

thalamus; (3) the nucleus accumbens; (4) the

basal ganglia; and (5) the cerebellum.

There are three types of neurons: sensory

neurons, motor neurons, and interneurons

(most neurons are interneurons). Neurons

communicate with each other to create pat-

terns of activation—brain circuits—which are

organized into large brain systems; these sys-

tems may be disrupted in cases of psychopa-

thology. A neuron has a cell body, an axon that

SUMMING UP

S fN l i l

functioninginanemergencywiththefight lobeSubcortical(beneaththecortex)areas