2.5 SUMMING UP

Neurological Factors in Psychological Disorders

• The nervous system has two major parts: the central nervous system (CNS), which is composed of the brain and spinal cord, and the peripheral nervous system (PNS), which is composed of the sensory-somatic nervous system and the autonomic nervous system (ANS).
• The ANS controls many involuntary functions, such as those of the heart, blood vessels, and digestive tract. The ANS has two major components: the sympathetic nervous system and the parasympathetic nervous system.
• The brain is divided into two hemispheres, left and right; each has four lobes: occipital lobe (involved in vision), parietal lobe (e.g., involved in processing spatial information and self-awareness), temporal lobe (e.g., involved in processing auditory information, including speech, and memory), and frontal lobe (e.g., site of executive functioning).
• Subcortical (beneath the cortex) areas of importance include the limbic system, which plays a key role in emotions, key parts of which are the hypothalamus, the amygdala, and the hippocampus.
• There are three types of neurons: sensory neurons, motor neurons, and interneurons. Neurons communicate with each other to create patterns of activation in brain circuits, which in turn are organized into large brain systems; these systems may be disrupted in cases of psychopathology.
• There are many types of neurotransmitters, which play different roles in the brain; imbalances of neurotransmitters can contribute to psychological disorders.
• Hormones, chemicals produced by glands in the endocrine system, can affect the functioning of neurons.
• Genes can influence the development of psychopathology. Heritability is an estimate of how much of the variation of a characteristic across a population, in a specific environment, is determined by genes.
• Behavioral geneticists may use twin and adoption studies to determine the relative influences of genes and environment.

Psychological Factors in Psychological Disorders

• Three types of learning can contribute to psychological disorders: classical conditioning of emotional responses such as fear and anxiety; operant conditioning of voluntary behaviors through positive and negative reinforcement and punishment; and observational learning, which can guide the observer’s behaviors and expectations.
• Mental processes and mental contents play important roles in the etiology and maintenance of psychological disorders.
• Emotional disturbances contribute to some psychological disorders. Such disturbances include not feeling or expressing emotions to a normal degree and having difficulty regulating emotions.
• Emotions, behaviors, mental contents, and mental processes are often intertwined, and so disturbances in one will affect the others. Moreover, a person’s attributions and mood can affect each other.
• Emotions involve both a psychological and a neurological response to a stimulus.
• Having a particular temperament may make a person especially vulnerable to certain psychological disorders, even at an early age. Evidence indicates that genes contribute strongly to temperament; however, the effects of genes need to be considered within the context of specific environments.
• Temperament is conceived of as having four dimensions: novelty seeking, harm avoidance, reward dependence, and persistence. Cloninger proposed that each of these dimensions is associated with the action of a particular neurotransmitter.

Social Factors in Psychological Disorders

• Social factors can help protect us from developing psychological disorders, or they can make us more vulnerable to or exacerbate psychological disorders. Such factors begin to exert their influence before adulthood.
• A family’s style of interacting that involves high expressed emotion can contribute to relapse in patients with schizophrenia from particular ethnic or cultural groups.
• Being maltreated as a child indirectly contributes to the development of psychological disorders by increasing stress, teaching maladaptive behaviors, promoting biases in discriminating among and responding to facial expressions, creating difficulties in attachment, and increasing social isolation.
• Psychological disorders in parents can contribute to psychological disorders in their children, although it is difficult to pinpoint the specific mechanism through which this influence occurs.
• Social support can buffer against stress, and a lack of social support can make people more vulnerable to psychological disorders.
• Low SES is associated with a higher rate of psychological disorders; both social causation and social selection contribute to this relationship.
• Being the object of discrimination is associated with an increased risk of distress and psychological disorders.
• Different personality traits and behaviors are valued in different cultures; thus, acculturation can lead to conflict among family members, creating stress and a risk of psychological disorders.