Neurobiological And Biological Relationships Of Major Depressive Disorder

Major depression is a commonly diagnosed psychological disorder affecting individuals’ ability to feel happiness and peace of mind. Those who suffer experience negative emotions, lack of motivation, changes in behaviour and dysfunctional cognitive symptoms. Depression is classified by the Diagnostic and statistical manual of mental disorders Fifth Edition (DSM-5) as five of more of the listed symptoms present persistently over the same two weeks. One of these symptoms must be depressed mood or loss of interest in previously pleasurable activities. Depression causes disruption to typical daily life such as inability to maintain friendships and jobs. Other symptoms outlined by the DSM-5 include; insomnia, fatigue and recurrent thoughts of death. There is much debate over what exactly causes depression. Biological explanations question hereditary and neurotransmitter factors. While psychological theories include the cognitive ideas of Beck’s negative triad and hopelessness theory. This essay will focus on the ways in which psychological and biological explanations contrast and how their theories can overlap to better understand depression.

The 2007 National Survey of Mental Health and Wellbeing Results revealed that at some stage in their lives, up to 45% of Australians will experience a mental illness, with 20% of the Australians surveyed in the 16-85 age group having experienced a mental illness within the 12 months preceding the survey

The term major depressive disorder was created by a group of US clinicians in the mid-1970s as part of proposals for diagnostic criteria based on patterns of symptoms (Spitzer et al, 1975). MDD made its first appearance in the third edition in the Diagnostic and Statistical Manual of Mental Disorders (DSM III) (Phillip, Maier & Demo, 1991). MDD is a mental disorder characterized by an impairment of functioning in one or more areas of life due to a depressed mood and loss of interest in activities combined with other symptoms for a minimum of two weeks (APA, 2013, 161).

The leading theory explaining the biology of depression is the monoamine hypothesis of depression. (Stahl, 3) This theory suggests that depression is caused by a deficiency in one or another of the three neurotransmitters: serotonin, norepinephrine and dopamine. The theory was formulated after the accidental discovery of the original drugs for depression and psychosis, much in the same way Fleming discovered penicilin.

However, at the time of publication, DMDD was unsupported by empirical evidence (Axelson, 2013). Instead, DMDD is an adapted version of severe mood dysregulation (SMD), conceptualised as a broad-phenotype of PBD (Leibenluft, Charney, Towbin, Bhangoo, & Pine, 2003). Following the elimination of the hyperarousal criterion and a decrease in the age of onset criterion, DMDD is left with just two symptoms; (1) persistently irritable or angry mood, most of the time and, (2) severe, recurrent temper outbursts inconsistent with developmental level and grossly disproportionate to the situation (for full diagnostic criteria see: APA, 2013). Neither empirical nor anecdotal justifications for the modifications have been provided by the DSM-5 work group, although it is reasonable to suggest the elimination of the hyperarousal criterion was intended to clarify the boundary between DMDD and BD/ADHD. As for the age of onset adjustment, reasoning remains elusive (Copeland et al., 2013; Hart, 2014; Johnson & McGuinness, 2014; Rao, 2014).

TCAs, SSRIs, SNRIs, SRMs, MAOIs and Lithium Salts) providing a variable range of options that help in considering patients’ preferences along with overcoming antidepressants tolerance and resistance issues. Nevertheless, despite the availability of more than two dozens different antidepressants, these treatments often yield inadequate results, for instance; up to 70% of patients with MDD (Major Depressive Disorder) do not reach remission with an adequate course of one antidepressant and experience poorer long-term outcomes (Fava 2003).The failures and shortcomings of classical antidepressants are usually rationalized through illustrating the hypothesis of their

Major Depression Disorder affects all areas of life for the person living with major depression disorder. When depressed, people struggle to perform normal everyday activities. They have trouble concentrating on their work, they tend to isolate themselves from social activities, become lethargic, and lose the ability to enjoy things that used to bring them pleasure such as eating and sex. Cognitive impairments are now recognized as a significant facet of major depressive disorder (MDD) (Snyder, 2013). The brain plays a vital role in fostering survival in life and reproduction among species. When are brains are malfunctioning in ways such as in depression if affects all aspects of a person’s life. Psychologists have

A deficiency in both serotonin and norepinephrine neurotransmitters specifically in the locus coeruleus, and the dorsal raphe nucleus, which both are important in relations to serotonin receptors can cause depression in AD. Individuals who had both AD and depression showed fewer neurons in the two locations when compared to non-demented individuals (Modrego, 2010 as cited by Zubenk, Moossy & Knopp, 1990). The use of animal shows the links of depressive behavior and AD. Ledo et al. (2016) used a mouse model to show an association of amyloid beta oligomers (AβOs) and depressive like behavior. It was hypothesized that AβOs induced depressive behavior in AD by causing an inflammatory response, which was triggered by activation of microglial cells. Ledo et al. (2016) found that AβOs decreased serotonin levels in the mice. This suggest that the decrease levels in the brains are leading to abnormalities in the AβOs, which then causes cognitive impairments.

Depression is a normal emotional reaction to perceived loss and hopelessness (Segal, Williams, & Teasdale, 2002). There are a number of different types of depression such as chronic depression, manic depression and the primary focus of this essay Major Depressive Disorder (MDD). MDD is a clinical depression, which is more chronic and more severe compared to other types of depression. It significantly disrupts the individual’s ability to meet the normal demands of life. According to many clinicians, clinical depression should be considered as a medical illness in need of medical intervention. Other mental health professionals believe this is an overstatement of the role of physiology and the

(3) While successful drug therapies which act on neurotransmitters in the brain imply that depression is a neurobiological condition (4), the fact that such medications do not help about 20 percent of depression-sufferers seems to show that not all depression is due to such imbalances. Rather, depression is not caused by one single factor; it is most often caused by many different things. Genetics, biochemical factors, medicines and alcohol, developmental and other external factors, and relationships, marriage and children all have effect on the development of clinical depression. (5) The strongest hypotheses on the pathways to depression are in decreases in the activity of specific neurotransmitters, or the overactivity of certain hormonal systems. (3)

Major Depressive disorder or MDD ,also known as depression is a common ,debilitating disorder affecting almost 16 million adults in the US every year(as found in the reference ranging in severity from mild to severe.It is a leading cause of global disease burden and it is projected that it will be only second to HIV/AIDS syndrome by 2030.It is characterized by symptoms such as fatigue, lack of motivation, decreased concentration and lassitude, which complicate the depressive state by impairing social and occupational functioning. Some of these defining symptoms are thought to occur due to reduced noradrenergic activity which exacerbates the depressed mood state. Feelings of sadness and other symptoms interfere with a person’s ability to work, sleep, study, eat, and enjoy once-pleasurable activities.

According to Morgan (2015), the neuroscience of depression has an emotional impact on many areas of the brain. The stressors in the hypothalamus pituitary adrenal axis initiate the release of the

The neurotransmitters norepinephrine, serotonin is also thought to play a role in depression (Porth 1371).  There are decreased levels of these neurotransmitters present in the pre and post synaptic cleft.  Dopamine levels have been studied and increased levels of dopamine are found in mania and decreased levels in depression (Porth 1372).

PMDD refers to a set of negative physiologic, emotional, behavioural and cognitive symptomatic changes that

The term depression is widely misused in today’s society. All human beings experience periods in life where they are sad for a relatively short period of time, which is considered normal. Those who experience sadness for extended periods may be suffering from depression. Two terms used to reference the classifications of depression, are Major Depressive Disorder, and Dysthymia. Individual diagnosis of these classifications is dependent on the length of time, and severity of symptoms experienced by the individual. The causes for these depressive states can be due to genetics or the insufficient production of neurotransmitters, which provide the brain with the data necessary to regulate one's psychological well being. Two examples