A nurse is administering a depression assessment tool to a client. The tool evaluates mood, anxiety, insomnia, somatic symptoms, and other aspects of depression. Which assessment tool is the nurse most likely using?

Choice A rationale:

Symptoms of major depressive disorder (MDD) are characterized by causing significant distress, not mild distress. The distress associated with MDD is usually severe and impairs daily functioning.

Choice B rationale:

While insomnia is a common symptom of major depressive disorder (MDD), it is not necessary for the diagnosis. Other symptoms, such as changes in appetite, psychomotor agitation or retardation, fatigue, and diminished interest or pleasure, can also contribute to the diagnosis.

Choice C rationale:

The correct answer. Symptoms of major depressive disorder (MDD) must not be due to a medical condition. It's crucial to rule out medical conditions that can mimic depressive symptoms, such as hypothyroidism or certain neurological disorders.

Choice D rationale:

The presence of a manic or hypomanic episode would indicate a diagnosis of bipolar disorder, not major depressive disorder (MDD). Bipolar disorder involves distinct periods of both elevated mood and depressive episodes.

Choice E rationale:

The correct answer. To meet the diagnostic criteria for major depressive disorder (MDD) according to DSM-5, an individual must experience five or more symptoms of depression during a continuous two-week period. These symptoms must include either depressed mood or loss of interest/pleasure. The scenario did not specify all the symptoms, but the persistent feelings of sadness, guilt, worthlessness, weight loss, and insomnia described align with the criteria.

Choice A rationale:

Acetylcholine and gamma-aminobutyric acid (GABA) are not the primary neurotransmitters involved in regulating mood, motivation, reward, cognition, and stress response. Acetylcholine plays a role in memory and muscle control, while GABA is an inhibitory neurotransmitter that helps regulate anxiety and sleep. These neurotransmitters are not as closely associated with the functions mentioned in the question.

Choice B rationale:

Glutamate is a major excitatory neurotransmitter in the central nervous system, and epinephrine (also known as adrenaline) is a hormone that prepares the body for the fight-or-flight response. While both glutamate and epinephrine play important roles in various physiological responses, they are not primarily responsible for regulating mood, motivation, reward, cognition, and stress response as mentioned in the question.

Choice C rationale:

Serotonin, dopamine, and norepinephrine are all key neurotransmitters involved in the regulation of mood, motivation, reward, cognition, and stress response. These neurotransmitters have been extensively studied in the context of mood disorders like Major Depressive Disorder (MDD). Serotonin is often associated with feelings of well-being and happiness, dopamine is linked to pleasure and reward pathways, and norepinephrine is involved in the body's stress response. Imbalances in these neurotransmitters have been implicated in the development of mood disorders.

Choice D rationale:

Endorphins and oxytocin are important neurotransmitters, but they are not as directly related to the regulation of mood, motivation, reward, cognition, and stress response as the neurotransmitters mentioned in choice C. Endorphins are known for their role in pain modulation and feelings of pleasure, while oxytocin is often referred to as the "bonding hormone" and is associated with social connections and childbirth.