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Most clinical trials of major depressive disorder (MDD) have focused on diagnosis and treatment of adults, but many younger and older patients also suffer from this condition. The prevalence of MDD is estimated to be 2% in children and 6% in adolescents.1 Up to 25% of adults age >60 experience MDD, dysthymic disorder, or “minor” depression.2
Although diagnosis and treatment of depression is similar regardless of a patient’s age, younger and older patients may not exhibit typical depressive symptoms (Table 1).1,2 For example, older adults may be more likely to report a lack of emotions than depressed mood. Vigilance for these types of distinct clinical manifestations can improve early recognition and treatment. In addition, evidence suggests there are differences in MDD treatment for younger and older patients.
This article reviews common challenges in recognizing and treating MDD in children, adolescents, and older adults.
Table 1
Major depressive disorder: Age-related differences
| Children/adolescents | Adults | Older adults | |
|---|---|---|---|
| Prevalence | 2% in children; 6% in adolescents | 20% | 25% |
| Male-to-female ratio | 1:1 in children; 1:2 in adolescents | 1:2 | 1:2 |
| DSM-IV-TR criteria | Similar | Similar | Similar |
| Clinical features | Irritability, temper tantrums, somatic complaints, hypersomina, weight gain, auditory hallucinations, psychomotor agitation, separation anxiety, social phobia, panic disorder, drug abuse, poor self-esteem | Typical DSM-IV-TR features. Psychomotor retardation, middle and terminal insomnia | Irritability, motor agitation, restlessness, somatic complaints, diarrhea and constipation, decreased libido, cognitive impairment, delusions, anxiety, panic, worsening of medical comorbidities |
| Source: References 1,2 | |||
Varying clinical features
Children/adolescents. The clinical presentation of MDD in children and adolescents is similar to that of adults. Children usually display anxiety, irritability, temper tantrums, and somatic complaints before verbally expressing depressive feelings. Psychotic depression in children manifests more often as auditory hallucinations than delusions.1
Younger vs middle-age adults. Researchers who evaluated baseline clinical and sociodemographic information of 1,498 patients enrolled in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study found that the presentation of depressive symptoms in young adult patients (age 18 to 35) differed from those of middle-age (age 36 to 50) patients.3 Younger patients were more likely to be irritable, complain of weight gain and hypersomnia, and have a negative view of life and the future. They also were more likely to report previous suicide attempts and endorse symptoms consistent with generalized anxiety disorder, social phobia, panic disorder, and drug abuse. Middle-age patients had more depressive episodes, deceased libido, and middle insomnia, and more frequently reported gastrointestinal symptoms such as diarrhea or constipation.3
Older adults. In our experience, typical MDD mood symptoms often are absent in older patients. Frequently, we see somatic complaints, motor restlessness, or psychomotor retardation; these symptoms may be attributable to a concurrent medical illness. This in turn may worsen the physical illness, leading to social isolation and considerable medical morbidity.4
Pain plays an important role in depression, particularly in older adults. Chronic pain affects up to 65% of older adults who live in the community and up to 80% of those who are institutionalized.5 The most common causes of pain in these patients are osteoarthritis, osteoporosis, fibromyalgia, degenerative disk disease, lumbar spinal stenosis, and scoliosis. In addition, neuropathic pain, such as post-herpetic neuralgia and peripheral neuropathy, and injuries resulting from falls often cause long-lasting pain.6
The presence of pain tends to negatively affect recognizing and treating depression. Regardless of their age, when a patient presents with pain or depression, investigate and consider treating both conditions.7
Memory decline is likely to be depressed older adults’ chief complaint, and when objectively tested these patients often show cognitive impairment.8 Whether depressive symptoms in this age group are a reaction to early cognitive deficits or are an early symptom of neurodegeneration remains controversial.9 Some case-control studies have found a link between a history of depression and Alzheimer’s disease (AD).10,11 In general, older patients whose first episode of depression occurs in late life have a higher relative risk of developing some form of dementia; research suggests that 50% of late-life MDD patients will develop dementia within 5 years.12
Researchers have considered the possibility that mild cognitive impairment (MCI) and dementia are a continuum of depression. In 1 study, 29 patients with MCI and 31 with MCI and MDD were assessed annually for an average of 4.3 years.13 Thirty-six patients with MCI (60%) progressed to AD. Presence of depression at the time of MCI diagnosis did not predict conversion to AD but persistence of depression for 2 to 3 years and the presence of melancholic features were associated with higher risk for AD.