A client asks a nurse about the differences between major depressive disorder (MDD) and dysthymia. Which of the following responses by the nurse is accurate?

Choice A rationale:

Signs of normal bereavement. Bereavement refers to the period of grief and mourning after the loss of a loved one. While fatigue and feelings of worthlessness can be experienced during bereavement, difficulty concentrating is not a typical sign. Additionally, bereavement-related symptoms typically improve over time as the individual processes their loss. The combination of extreme fatigue, difficulty concentrating, and thoughts of worthlessness suggests a more severe and persistent condition than normal bereavement.

Choice B rationale:

Symptoms of bipolar disorder. Bipolar disorder is characterized by alternating episodes of depression and mania (or hypomania). The client's symptoms of extreme fatigue, difficulty concentrating, and thoughts of worthlessness are primarily indicative of a depressive episode, which is only one aspect of bipolar disorder. Bipolar disorder requires the presence of manic or hypomanic episodes, which are not mentioned in the client's presentation.

Choice C rationale:

Indicators of substance-induced mood disorder. Substance-induced mood disorder occurs as a result of substance use or withdrawal and involves changes in mood and affect. While substances can lead to symptoms similar to depression, the combination of symptoms presented by the client (fatigue, difficulty concentrating, thoughts of worthlessness) is more indicative of a primary mood disorder rather than one directly caused by substance use.

Choice D rationale:

Criteria for diagnosing MDD according to DSM-5. The client's symptoms of extreme fatigue, difficulty concentrating, and thoughts of worthlessness align with the criteria for Major Depressive Disorder (MDD) as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). These criteria include the presence of specific symptoms for a specified duration, causing significant impairment in functioning. The symptoms should not be better explained by other conditions or substances. In this case, the client's presentation closely matches the criteria for diagnosing MDD.

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.