During the last century, and part of the one before, it was widely held that there was irreconcilable conflict between knowledge and belief.

                                                                    Albert Einstein

Models

We attempt to make sense of the puzzle of psychopathology by creating models of its development. This process often begins serendipitously and contributes to the evolution of understanding the etiology of mental disorders. These models then lead us to efforts at treatment (Wilson, Nathan, O’Leary, & Clark, 1997).  One such example is the treatment of schizophrenia. Scientists observed patients with Parkinson’s disease who exhibited delusional and hallucinatory  behaviors when exposed to excessive levels of dopamine (Carver, 2000; Woodruff, 2005).  Antipsychotic medications such as Risperdal, Zyprexa, Haldol, and Thorazine, thought to block dopamine receptor sites, are now primary forms of treatment for positive and negative symptoms of schizophrenia (Bank, 2005; Hertzman, 1992). Another example, behavioral in nature, occurred when Ivan Pavlov discovered fundamental conditioning processes by way of trying to unveil the secrets of the digestive system (Fredholm, 2001).  Today, these conditioning processes provide a basis for perspectives on the etiology and maintenance of anxiety disorders and are utilized as effective behavioral treatment interventions for a variety of anxiety disorders (Mineka & Zimbarg, 2006; Mackillop, 2005: Machulda, 1998).

It follows, that once the etiology of a disorder is thought to be understood, the most effective treatment for such disorder is suggested by that theorized cause.  What does not follow is a global generalization and rigid application of this logic.  There is good evidence to show that biological interventions can be helpful in dealing with mental health problems associated with environmental influences just as there are cognitive behavioral interventions that are demonstrably helpful in dealing with symptoms of disorders that are biological in origin.  For example, it is evident that anxiolytics such as Zanax, Ativan, or Valium, are proven effective biological treatments of symptoms associated with PTSD (e.g. anxiety, increased heart rate, hyper vigilance, etc.), an environmentally rooted disorder, while cognitive behavioral therapy techniques are helpful in managing delusional and reclusive behaviors in the schizophrenic patient (Butler, Chapman, Forman, & Beck, 2006; Hammer, Robert, Frueh, 2004; Maryasti & Pascal, 2004; Andreas, Verena, Dirk, Michael, Elmar, Birgit, Julia, Michael, & Joachim, 2005).    Nevertheless, there is clear and convincing evidence that chemical treatment of mental health disorders has escalated exponentially in recent years (Pincas et al, 1998; Angell, 2000; Glenmullin, 2000; Korcok, 2002; Good, 2003; Edwards, 2003; Vaczek, 2004; Bloice, 2005).  This gives rise to a credible postulate that an increasingly popular belief system within the mental health community is that many mental health disorders have a large biological/chemical basis for existence.

Biological Causation

             The contemporary biological model of abnormal behavior assumes that the principle causes of, and the most likely effective treatments for, abnormal behaviors are biological (Wilson et.  al, 1997; Carver, 2000; NAMI, 2005). Biological theorists view abnormal behavior as caused by a physical illness or injury.  Most often, they point to a malfunctioning brain as the cause of abnormal behavior, focusing particularly on problems in brain structure, brain chemistry, or genetic makeup (Mesulam, Human, Hobson, & Silvestri, 1999; Schwartz, 1999).

             The diagnostic task of defining an organic contribution to the etiology of abnormal behavior involves two basic steps:  1) identifying a specific organic factor based on evidence from history, physical examination, and/or laboratory tests; and 2) judging the factor to be etiologically related to the behavioral disturbance (Reid, Balis; Sutton, 1997).

Structural brain imaging techniques, such as Computed Axial Tomography (CT Scan – a form of advanced X-ray technology) and Magnetic Resonance Imaging (MRI - a spectroscopic technique used by scientists to obtain microscopic chemical and physical information about molecules), are at times touted as preferred methods in psychiatric diagnosis (Sadock & Sadock, 2000). However, when unusual brain structures or activity are observed in a person who exhibits overt abnormal behavior, it is unclear whether the brain abnormalities cause, are caused by, or are unrelated to the overt behavior.  It is also possible that some third factor, or set of factors, caused both the overt abnormal behavior and the unusual brain structure noted on testing.  Yet, such correlational data, when reported by researchers, may be misinterpreted as evidence of causation.

It is important to point out that biological abnormalities are known to cause some abnormal behaviors.  For example, structure changes to the cerebrum may result in dementia.  Dementias are typically classified according to the general brain areas involved and include cortical changes [Alzheimer’s disease, Pick’s disease], subcortical [Huntington’s disease, Parkinson’s disease], and axial [Wernicke-Korsakoff syndrome] (Heilman & Valenstein, 1979).  There is universal agreement that other disorders such as Down’s syndrome and Autism are the result of biological abnormalities.  The same is true for other disorders such as those attributable to brain tumors, intracranial infection, and toxins (e.g., lead exposure).  However, many other disorders (e.g., depression, anxiety, ADHD, schizophrenia) are typically of unknown origin.  In such cases, it is tempting to make unwarranted attribution to unobserved structures or functions of the central nervous system.  Skinner (1974) labeled this phenomenon the “conceptual nervous system” as if to point out its illegitimacy.  Skinner termed the CNS a “dumping ground” where the cause of any unexplained abnormal behavior is hypothesized to lie.

Although computerized brain-imaging technologies promise to open new doors in the study of the gross (large-scale) anatomy and function of the human brain, it is microscopy that contributes to the analysis of the cellular structure and, more recently, the cellular function of the nervous system.  This particular means of investigation has fueled speculation that various disorders are due to chemical imbalances in the brain.

             The brain is estimated to be made up of approximately 100 billion nerve cells, called neurons, and thousands of billions of support cells, called glia (Comer, 2001).   Researchers into brain anatomy have speculated that there may be a connection between psychological disorders and chemical exchanges between neurons.  A tiny space, the synapse, separates one neuron from the next.  Hypothetically, when a thought, feeling or behavior occurs, chemicals called neurotransmitters are released and travel across the synaptic spaces to the receptor sites of other neurons.  Those who subscribe to the biological causation worldview theorize that a given behavioral problem may be the result of too little or too much of one or more neurotransmitters reaching the receptor sites.  Although there is no reason to believe that such a chemical imbalance could not cause disordered thoughts, feelings and overt behaviors, the exact mechanism and processes remain unknown.  It is worth noting that there is little evidence that directly supports this theory (Antonuccio, Danton, DeNelsky, Greenberg , &  Gordon, 1999; Wyatt, 2003).

A branch of biological causation theory holds that abnormal activity by certain neurotransmitters is associated with, and may cause specific behavioral disorders such as depression and anxiety (Gershon & Reider1992; Robert, Aubin, & Darcourt1999).  This belief is built upon a top-down reductionistic analysis of abnormal behavior, which reduces complex social interaction and other behaviors to activity at the cellular level (Kohn, 1984).  This at times leads to illegitimate “explanations”.  For example, if a child is given methylphenidate (Ritalin) for hyperactive behavior and the family then reports improved behavior, then it is (reductionistically) assumed that the drug’s dopamanergic effect (Plomin, 2002) substantiates an underlying brain chemistry abnormality which was casual for the hyperactive behavior.  This style of deductive reasoning is also erroneously applied to use of other drugs that are prescribed for other behaviors, such as anti-depressants for mood disorders (Nierenberg, McLean, Alpert, Worthington, Rosenbaum, & Fava, 1995).  Read more commentary regarding the study of drug efficacy. 

Donna M. Midkiff, PsyD