Differential diagnosis and clinical challenges

The diagnosis of depression in older adults presents multiple challenges due to the frequent coexistence of medical illnesses, cognitive impairment, and changes associated with aging. This clinical complexity requires careful evaluation to distinguish between depressive symptoms and manifestations of other conditions.

Depression versus medical illnesses

One of the main diagnostic difficulties is differentiating depression from certain chronic physical illnesses. For example, hypothyroidism can present symptoms such as fatigue, psychomotor slowness, and sadness, which overlap with those of depression.

Similarly, diseases such as diabetes or myocardial infarction can produce similar symptoms (asthenia, lack of interest, sleep or appetite disturbances), or even trigger a depressive episode due to the psychological impact of the diagnosis.

That is why laboratory tests (such as thyroid function, blood sugar, or vitamin B12 tests) are essential to rule out medical causes before establishing a primary psychiatric diagnosis.

Depression versus cognitive impairment

Another important challenge is distinguishing between depression and dementia, especially Alzheimer's disease. Both can present with changes in memory, language, attention, or concentration. However, in depression, these cognitive deficits tend to improve with mood treatment, while in dementia they are usually progressive and irreversible.

In addition, depressed older adults are usually aware of their impairments and actively complain about them, in contrast to the lower level of awareness of illness seen in dementia. This differentiation is crucial, as the prognosis and therapeutic approach differ significantly.

Depression secondary to cerebrovascular events

Depression can also be a direct consequence of brain damage, as in cases of cerebrovascular disease. “Vascular depressive disorder” has been described, characterized by late onset, greater psychomotor involvement, and fewer traditional affective symptoms. Lacunar infarcts in the frontal lobe or lesions in the basal ganglia can alter neural circuits involved in mood regulation.

This type of depression is often accompanied by increased apathy, slowness, and executive function impairments, which can also be confused with cognitive decline. Neuroimaging (such as magnetic resonance imaging) is a useful tool in these cases.

Importance of timely diagnosis

The underdiagnosis of depression in older adults is an alarming reality, with estimates reaching up to 67% of cases unidentified. This omission has serious consequences: increased use of medical services, functional decline, caregiver overload, and increased risk of suicide.

Social stigma, the tendency to normalize sadness in old age, and the predominantly somatic presentation (pain, fatigue, insomnia) contribute to this situation. Therefore, adequate training of healthcare personnel, the systematic application of screening scales such as the Yesavage scale, and the implementation of multidisciplinary approaches are essential.