Читать книгу Abnormal Psychology - William J. Ray - Страница 179

As noted, there has been a push to find more objective markers that can be used in the diagnosis and treatment of mental disorders using neuroscience research. With the advent of the various levels of analysis available to neuroscientists including brain imaging, genetics, biochemical and electrophysiological processes, brain networks, behavior, and experience, a variety of researchers have sought to describe cognitive, emotional, and motor processes in both health and illness. This has resulted in a better articulation of what underlies these processes.

One such underlying process is memory. It is possible to describe its underlying process including specific brain areas such as the hippocampus, the brain networks involving memory, and the biochemical and structural changes among neurons as new information is retained. With this knowledge, it is also possible to explore psychopathological conditions such as amnesia or delusions that involve the memory system.

Figure 4.5 Reward System of the Brain

Another example is the reward system. Humans seek rewards from a variety of sources, including food, sex, power, acclaim, and affiliation, as well as drugs. A number of studies show that particular brain structures, especially the nucleus accumbens part of the ventral striatum, are influenced by an increase in dopamine during a reward (see Figure 4.5). In fact, all addictive drugs result in dopamine release in the nucleus accumbens (Pittenger & Etkin, 2008). Individuals with alcoholism show greater activation to alcohol-related cues in the nucleus accumbens and the anterior thalamus. The activation of the nucleus accumbens also correlates with the degree of craving. One approach involving the reward system is to note its involvement in active reward processes such as those seen in addiction or mania as well as those disorders in which reward is reduced such as depression or schizophrenia (Russo & Nestler, 2013).

reward system: particular brain structures, especially the nucleus accumbens part of the ventral striatum, influenced by an increase in dopamine during a reward

Since the beginning of the twenty-first century, a number of researchers and clinicians have asked whether it would be possible to use neuroscience approaches to classify mental illness and inform its treatment (Cuthbert & Insel, 2010; Halligan & David, 2001; Hyman, 2007, 2010; Insel, 2009; G. Miller, 2010; Sanislow et al., 2010). Part of this desire stems from the fact that not all individuals with depression, for example, report the same symptoms. This suggests to some researchers that there might be different underlying brain processes involved in what appears as a single disorder. By knowing the underlying processes involved in a particular disorder, it would be possible to create a treatment that was specific to a given individual.

Neuroscience perspectives can also help validate theoretical constructs used in a variety of theoretical orientations. For example, Carhart-Harris and Friston (2010) examined the relationship between brain network processes and Freudian constructs. Likewise, DeRubeis, Siegle, and Hollon (2008) examined the different pathways of treatment for depression found in cognitive therapy versus medication. These researchers suggested that cognitive therapy works through a top-down approach by increasing higher cortical functioning associated with the frontal lobes, whereas medication works in a more bottom-up approach by decreasing excessive emotional responsiveness associated with the amygdala.

National Institute of Mental Health (NIMH): agency of the U.S. government that advances the understanding and treatment of mental disorders

One large organization emphasizing the utilization of neuroscience information to understand mental illness is the National Institute of Mental Health (NIMH) in the United States (Insel, 2009). Through its research mission, NIMH developed four major objectives:

The plan calls for research that will (1) define the pathophysiology of disorders from genes to behavior, (2) map the trajectory of illness to determine when, where, and how to intervene to preempt disability, (3) develop new interventions based on a personalized approach to the diverse needs and circumstances of people with mental illnesses, and (4) strengthen the public health impact of NIMH-supported research by focusing on dissemination science and disparities in care. (Insel, 2009, p. 128)

Former director of the National Institute on Drug Abuse (NIDA), Dr. Alan I. Leshner, discusses PET scans showing brain activity before and after use of the drug MDMA (ecstasy).

Michael Smith/Staff/Hulton Archive/Getty Images

As can be seen, the objectives are designed to identify the manner in which brain processes are involved in a specific disorder, to better describe the course of a mental disorder including when the first signs appear—even if abnormal processes are not yet seen—so as to use this knowledge to create a treatment related to a given individual, and to make these treatments available to all members of society. Thus, traditional neuroscience perspectives that reflect action on the level of genetics, the neuron, and neural networks are integrated with research perspectives related to more system-level cognitive, emotional, and behavioral processes. See LENS: Assessment, Classification, and Clinical Practice: The RDoC Alternative to the DSM later in this chapter for a discussion of the Research Domain Criteria (RDoC) approach that is being explored by NIMH.

Concept Check

 Why is the reliability of diagnosis an important aspect of psychological treatment?

 What does it mean that mental disorders can be described in both a categorical and a dimensional manner?

 Why is comorbidity of psychological disorders an important consideration? Discuss some of the advantages of including underlying processes in the study of psychopathology.

 Identify three specific ways in which neuroscience approaches have been utilized to classify mental illness and inform its treatment.