Author is talking about the causes of cognitive disorders (like dementia). This paragraph is about emotional causes. I think the example (bolded) is not related to the first sentence. The first sentence is saying that psychological disorders have some features that may seem like organic disorder, but the example says that organic disorders (like hypothyroidism) have symptoms which are like depression (as a psychologic disorder). (And none of them are related to the causal effects of emotional factors on organic disorder). Am I right?
Many stress-related symptoms mimic organic disorders. For example, depression can be a predominant symptom of hypothyroidism, Addison’s disease, and brain tumors. The psychiatrist must consider these possibilities before deciding that the illness is due to emotional conflicts. In older persons, depression can have the appearance of dementia, with confusion, recent memory loss, and poor functioning. Treating the basic depression can completely relieve this pseudodementia.
Source: Richard W. Roukema. What every patient, family, friend, and caregiver needs to know about psychiatry.