Report Writing Task on Major Depressive Disorder

Report Writing Task on Major Depressive Disorder

Epidemiology states for a set of different methods that can help to support inferences regarding a particular disease. The epidemiological studies are often done by using population based samples of large size in order to avoid bias and relationships are established to measure risk factors. Bipolar disorder is a common mental disorder both in adults and children and the core of the disease is unpredictable mood swings along with mania and depression. There are combinations of clinical indicators that can be used for diagnosis of bipolar disorder. 

There are a couple of common clinical indicators among patients but the individual symptoms are not specific and they vary during course of disease. Some of the common symptoms are domination of irritable mood with hyperactivity, aggressiveness and excessive energy. Patients are also found to be suffering with delusions and in severe case hallucinations. The clinical representation of the disease is complex and therefore it has been generalized as a group of mood associated disorders with a wide spectrum (Zhang et al., 2013). 

The disease can be caused by both genetic and environmental risk factors and studies have shown that there is a very low estimate of genetic risk. However, there is enough evidence that suggest the presence of genetic risk factors as clinicians do suggest that families with history of bipolar disorder leave several generations at risk of developing the disease at an early age of life. The non-genetic, environmental and social risk factors that contribute to bipolar disorder are drug abuse, substance abuse and sexual abuse (Gershon et al., 2013). 

Three different methods that can be used to establish and elaborate the hypothesis that support mental disorders like bipolar disorder, schizophrenia are genetic and they run in family tree for several generations (Lahey, D'Onofrio and Waldman, 2009): Multivariate Behaviour Genetic Analysis: Genetically informative samples of representative twins that are used as samples are being taken in order to make multivariate genetic analysis of psychopathology and different dimensions of it. There are differences that exist between monozygotic and dizygotic twins in cross trait, cross twin correlation.

  • Genetic and Environmental Factor Analysis: The factor structure of DSM-IV symptoms are examined on the basis of correlation between genetic and environmental risk factors using genetically informative samples. In the factor analysis approach, the phenotypic analysis is subjected to correlation among several symptoms. The phenotypic relations between symptoms suggest that the symptoms have same or correlated genetic influences. So, the symptoms that have defined dimension at phenotypic level can be similar or co-vary because of common genetic and environmental influences.
  • Trajectory Analysis: There are several evidence of marled differences depending on whether the disease showed an on-set in childhood or at adolescent age. The development trajectory shows differences on the basis of genetic influences. It also shows that if development trajectory will not be considered while making an analysis then there will be no point of making a factor analysis on the basis of genetic and environmental influences. There are several researches that are to be done on development trajectory in order to use them effectively during a genetic analysis.


Gershon, E., Grennan, K., Busnello, J., Badner, J., Ovsiew, F., & Memon, S. Et al. (2013). A rare mutation of CACNA1C in a patient with bipolar disorder, and decreased gene expression associated with a bipolar-associated common SNP of CACNA1C in brain. Molecular Psychiatry, 19(8), 890-894. Doi: 10.1038/mp.2013.107

Lahey, B., D'Onofrio, B. and Waldman, I., 2009. Using Epidemiologic Methods To Test Hypotheses Regarding Causal Influences On Child And Adolescent Mental Disorders. [online] Available at: < 7610.2008.01980.x> [Accessed 29 April 2020].

Zhang, J., Cai, J., Zhang, X., Ni, J., Guo, Z., & Zhang, Y. Et al. (2013). Does the Bipolar Disorder-Associated CACNA1C Gene Confer Susceptibility to Schizophrenia in Han Chinese?. Journal Of Molecular Neuroscience, 51(2), 474-477. Doi: 10.1007/s12031- 013-0079-4