A nurse is discussing the theories that explain the biological basis of Major Depressive Disorder (MDD) with a group of nursing students. Which theory suggests that depression is caused by an imbalance of neurotransmitters in the brain that regulate mood, motivation, reward, cognition, and stress response?

Choice A rationale:

The correct answer. A positive family history of mood disorders is a well-established risk factor for developing major depressive disorder (MDD). Genetic factors play a significant role in predisposing individuals to MDD, making it more likely to develop if there's a family history of mood disorders.

Choice B rationale:

Optimistic personality traits are not considered risk factors for developing major depressive disorder (MDD). In fact, having an optimistic personality might serve as a protective factor against developing MDD.

Choice C rationale:

The correct answer. Young age is a risk factor for developing MDD. Adolescents and young adults are particularly susceptible to the onset of depressive disorders due to hormonal changes, emotional challenges, and life transitions during this developmental stage.

Choice D rationale:

High socioeconomic status is not a consistent risk factor for developing major depressive disorder (MDD). While individuals from various socioeconomic backgrounds can develop MDD, the factors contributing to its development are more complex and not solely dependent on socioeconomic status.

Choice E rationale:

The correct answer. Chronic medical conditions are risk factors for developing major depressive disorder (MDD). The stress, emotional toll, and physiological effects of living with a chronic illness can contribute to the onset or exacerbation of depressive symptoms.

Choice A rationale:

Chronic stress is known to activate the Hypothalamic-Pituitary-Adrenal (HPA) axis, which leads to increased cortisol production. While cortisol is important for various physiological functions, chronic elevation of cortisol due to stress can actually have detrimental effects on the brain. Elevated cortisol levels have been associated with impaired neurogenesis (the formation of new neurons) and synaptic plasticity (the ability of synapses to change and adapt), both of which play crucial roles in maintaining cognitive function and mental health.

Choice B rationale:

This statement is not accurate. Chronic stress typically leads to hyperactivity, not hypoactivity, of the HPA axis, resulting in increased levels of cortisol. The increased cortisol levels can negatively impact neurogenesis and synaptic plasticity, which are key factors in depression and cognitive function.

Choice C rationale:

This is the correct statement. Chronic stress triggers hyperactivity of the HPA axis, causing elevated levels of cortisol. While cortisol is meant to help the body cope with stress in the short term, chronic elevation can lead to adverse effects on the brain. High cortisol levels have been linked to impaired neurogenesis and synaptic plasticity, contributing to the development of depression and cognitive deficits.

Choice D rationale:

This statement is not accurate. Chronic stress tends to lead to hyperactivity of the HPA axis and elevated cortisol levels. Reduced cortisol levels, as suggested in this choice, are not commonly associated with chronic stress and its impact on depression.