Final answer:
Depression symptoms include lethargy and this is consistent with Christine's presentation. Lethargy is particularly characteristic of disorders like Seasonal Affective Disorder, where melatonin levels can play a role. Non-drug therapies like light therapy and addressing thyroid hormone levels can be important in managing such symptoms.
Step-by-step explanation:
Depression can be characterized by many symptoms such as sadness, lethargy, and appetite changes. Its manifestations can vary greatly from person to person, but a common symptom is indeed lethargy, as seen in Christine's case. Depression may result in feelings of inactivity and lethargy, as can be seen with conditions like Seasonal Affective Disorder (SAD) or major depressive episodes. Indeed, major depression is noted for its ability to disrupt normal functioning by inducing intense sadness, a lack of energy, and physical changes like weight fluctuation.
Regarding the role of melatonin in SAD, this hormone, which is influenced by light exposure, can contribute to symptoms of depression when produced at higher levels during the extended nights of winter months. A non-drug therapy for SAD could include light therapy, which aims to alter melatonin production thereby alleviating depression symptoms associated with the disorder.
Additionally, a deficiency in thyroid-stimulating hormone (TSH) can contribute to weight gain and fatigue due to its role in regulating metabolism. Less TSH means lower thyroid hormone levels, resulting in a deceleration of the metabolism which can make one feel tired and lead to weight gain.