PSY3 Brain Disorders 14141847
Discuss the evidence that while depression and schizophrenia are distinct psychiatric disorders, there may be some parallels and/or similarities as well as differences in the underlying biological mechanisms. Refer in your answer to recent experimental studies that have advanced our understanding of the underlying causes and the brain pathology of these two disorders.
Schizophrenia is a disorder categorised by a separation between thought and reality. It involves positive symptoms such as hallucinations and delusions as well as negative symptoms such as anhedonia. Depression or ‘affective disorders’ consists of major depressive disorder and bipolar disorder. Both involve a low mood and lack of motivation across numerous aspects of day-to-day life with bipolar also including episodes of mania. These disorders at face value sound incredibly different from one another due to having many distinguishable features. Overall, depression and schizophrenia are two long-term brain disorders with a distinct criterion which is used for diagnosis. However, some may argue that the features of these two illnesses can overlap in certain areas. The underlying biological mechanisms of both schizophrenia and depression have various similarities and differences which this essay will explore.
Eugen Bleuler (1911/1950) invented the term schizophrenia, which translates to ‘split mind’, meaning a break from reality. Prevalence is approximately 1% across all sexes and cultures developing around late adolescence to young adulthood onwards (Mueser & McGurk, 2004). Cognitive, positive and negative symptoms but be present for the diagnosis of schizophrenia. Positive symptoms are well-known in relation to schizophrenia as they are the symptoms which present themselves openly, they include thought disorder (disorganised, irrational thinking), hallucinations (sensory experiences which contrast to reality) and delusions (beliefs which contrast to reality). Cognitive and negative symptoms tend to overlap with one another, with negative symptoms including a dampened emotional response and lack of initiative and cognitive symptoms including lack of attention and low psychomotor speed.
Major depressive disorder is a type of affective disorder which can range in severity. Although many people feel depressed occasionally, diagnosis of depression occurs when this low mood extends over a long period of time and cannot be justified by reality (e.g. bereavement). It has a prevalence of 3% in men and 7% in women which implies that it is the fourth leading cause of disability (Kessler et al., 2003) and can occur at any point in an individual’s life. Other than a low mood, people characterised depression by a lack of energy and slow speech as well as lack of pleasure (i.e. anhedonia). Sleep is also an important factor in relation to depression, as circadian rhythms are disrupted, causing those with depression to oversleep or only have shallow sleep. Those with...