The average life expectancy of China’s population exceeds 70 years, and the proportion of the elderly population in the total population exceeded 10% in 2000, making China a truly aging society. The increase in the elderly population in China will inevitably lead to an increase in mental health problems among the elderly. Among them, depression is one of the more common mental disorders in the elderly.
A number of foreign studies have shown that the prevalence of depression among the elderly in the community is about 5%. In addition, 10% to 20% of older adults have depressive symptoms. Domestic epidemiological studies on geriatric depression show that the prevalence rate is 1.57%, with 2.23% among women, which is significantly higher than that of men (0.58%).
The etiology of geriatric depression is still being explored. It is generally believed that the brain regions associated with emotional responses are the amygdala, hypothalamus, limbic dopamine pathway in the midbrain, temporal lobe, orbital and dorsolateral parts of the frontal lobe. Recent brain imaging studies suggest that atrophy of the frontotemporal lobes and lesions of the frontal white matter are present in elderly patients with depression. Impairment of the “striato-pallidum-thalamo-cortex” pathway leads to dysfunction of neurotransmitters associated with mood control, such as norepinephrine and pentraxin, leading to depression.
Compared with younger patients, geriatric depression is characterized by the following features: positive family history is rare, neurological and somatic diseases account for a large proportion, cognitive impairment, complaints of physical discomfort, and strong suspicion; weight change, early awakening, loss of libido, and lack of energy become less prominent due to age; some geriatric depressed patients may be mainly irritable, aggressive, and hostile; insomnia, loss of appetite Some elderly depressed patients may have irritability, aggression, hostility, insomnia, loss of appetite, emotional vulnerability, and volatility; sadness is often not well expressed; suicidal ideation is often not clearly expressed, e.g., the patient may say, “Let me die with a shot!” but deny that they have suicidal thoughts. In terms of diagnostic classification, it is important to note that secondary depression accounts for a significant proportion of depression. The physical diseases that can cause depression are: heart disease, thyroid disease, malignant tumor, adrenal disease, and metabolic disorders, in that order. Clinical data show that stroke and Parkinson’s disease are also very closely related to depression. Many drugs commonly used by the elderly such as metformin, reserpine, colesevelam, tretinoin, levodopa, amantadine, valium, guanethidine, insulin, steroids, etc. can also cause depression. The differential diagnosis should be differentiated from dementia with agitation (patients with dementia may become irritable due to some somatic complaints such as pain and urinary retention), comorbidities of treatment (e.g., valium withdrawal reactions), the effects of somatic diseases, and deterioration of previous personality traits.
In 1997, Cole et al. summarized the outcome of geriatric depression in a meta-analysis as follows: 27% recovered, 32% relapsed after recovery, 14% were in a persistent 31% died or developed dementia during the follow-up. Several studies have compared the outcome of depression in older adults with that of depression in younger adults and found no significant difference between the two. The inconsistent findings may be related to the heterogeneity of the study population, e.g., in geriatric depression, late onset depression has a significantly worse prognosis than early onset depression, while secondary depression, such as vascular depression, clearly has a poor prognosis.
Treatment of geriatric depression
(1) Acute treatment
In the treatment of elderly patients with depression, the following factors must be taken into account: (1) pharmacogenetic and pharmacodynamic characteristics of the elderly; (2) drug interactions; (3) physiological characteristics of the elderly make them more sensitive to adverse drug reactions, especially cognitive impairment; (4) psychosocial factors of the elderly are complex and can affect treatment regression.
So far, no single antidepressant has been found to be superior to other drugs in terms of efficacy. Among the traditional tricyclic antidepressants (TCAs), nortriptyline and nortriptyline are more often used in elderly depressed patients because of their low cardiovascular adverse effects, and the efficacy of TCAs is 30% to 50% higher compared with placebo.
The new generation of SSRIs (selective 5-hydroxytryptamine reuptake inhibitors) are not significantly superior to TCAs in terms of efficacy, but have fewer adverse effects, are well tolerated, and therefore have higher adherence than TCAs in elderly patients. Trazodone is also generally regarded as an SSRI, but in addition to inhibiting 5-hydroxytryptamine reuptake, it also antagonizes 5-HT2.
Recent new antidepressants include mirtazapine (increases release of norepinephrine and 5-hydroxytryptamine and antagonizes 5-hydroxytryptamine 2 receptors), venlafaxine (dual 5-hydroxytryptamine and norepinephrine reuptake inhibitor), moclobemide (monoamine oxidase inhibitors, MAOIs), and bupropion (norepinephrine potentiation and dopamine reuptake inhibition). Unfortunately, information on the use of these new drugs in the elderly (including safety and efficacy) is limited.
Principles of antidepressant selection in elderly patients
Concomitant physical illnesses in the elderly: A significant number of older adults suffer from one or more physical illnesses and often require several medications for various physical illnesses in addition to antidepressant therapy. Special attention should be paid to the effects of adverse effects of antidepressants on physical illnesses and to the interaction of antidepressants with other medications. TCAs should be avoided if the patient has ischemic heart disease because they can increase the risk of arrhythmias during myocardial ischemia. Similarly, TCAs should be avoided in patients with diabetes and glaucoma. Long half-life SSRIs such as fluoxetine are not recommended for patients with liver disease to avoid increased accumulation of the drug. Citalopram, sertraline, and venlafaxine are ideal antidepressants for patients taking multiple drugs at the same time with few drug interactions. In addition, MAOIs are not recommended for patients who do not make good dietary choices (e.g., know how to avoid tyramine-containing foods) and are taking multiple prescription or over-the-counter medications at the same time.
Drugs with different pharmacological properties can be used depending on the clinical syndrome: fluoxetine, venlafaxine, bupropion can be used for depression with a predominantly sluggish nature, which has a good activating effect. Mirtazapine may be more effective if the agitation is obvious. For depressed patients with prominent anxiety, SSRIs such as paroxetine, citalopram, sertraline, fluvoxamine, venlafaxine and mirtazapine may be used. If the patient has persistent and severe insomnia, trazodone should be a better choice. If the depression is severe, venlafaxine or bupropion is recommended. TCAs may also be considered after careful weighing of the pros and cons. MAOIs are more effective than other drugs in patients with atypical depression with prominent symptoms such as drowsiness, bulimia, motor retardation, and emotional overreactivity. Fluvoxamine is an option for patients with obsessive-compulsive symptoms. For mild to moderate depression, botanicals such as St. John’s wort extract are available. John’s wort extract, but it has recently been reported that this drug can cause adverse effects similar to those of SSRIs.
Other factors that should be considered when choosing a medication are: ① Previous treatment history and family history. In general, drugs that have been effective in the past or have been effective in the family in treating patients with similar diseases are likely to be effective again. ② The patient’s tolerance level to specific adverse reactions. For example, some patients cannot tolerate dry mouth, and some patients find weight gain unacceptable. (iii) Cost. ④Adherence to treatment. For patients with poor compliance, long half-life drugs such as fluoxetine may be more appropriate.
In principle, low doses of antidepressants are more suitable for elderly patients, but recent studies have shown that low doses of antidepressant therapy not only tend to cause inadequate treatment and chronicity, but also tend to lead to relapse. The use of antidepressant therapy in the elderly should be based on the principle of “low starting dose and slow dose increase”.
The effectiveness of antidepressant treatment in the acute phase should be judged by waiting at least 6 weeks. Some experts suggest that 12 weeks is the appropriate duration of treatment to determine whether an elderly patient responds to the treatment.
Twitchless electroconvulsive therapy has been shown to be a safe and reliable treatment by a large number of clinical practices at home and abroad, especially for those patients who cannot tolerate antidepressant treatment, twitchless electroconvulsive therapy is the treatment of choice.
Many researchers have emphasized the need for psychotherapy in the treatment of elderly patients with depression. Most researchers agree that, considering the psychological characteristics of the elderly, the combination of cognitive psychotherapy should be a treatment routine, regardless of the biological treatment used.
(2) Maintenance therapy
In a study conducted, it was found that in elderly patients with depression over 60 years of age, the relapse rate was as high as 70% within 24 months after the first onset, and the remission period was gradually shortened. The older the age of onset, the greater the number of relapses, and the higher the risk of relapse. It is difficult to distinguish between maintenance treatment and preventive treatment in older patients with depression. Most researchers advocate that depressed patients over 60 years of age with a first episode of depression should be maintained on treatment for at least 12 months after achieving clinical recovery. In case of relapse, medication should be taken for more than 2 years, and in case of a second relapse, medication should be taken for life.
A major challenge in maintenance treatment is the compliance of older patients. A survey by the National Institutes of Health showed that up to 70% of elderly patients were willing to take only 50%-75% of the prescribed dose. One of the main reasons for poor adherence is the difficulty in tolerating the adverse effects of drugs. The selection of new antidepressants may reduce adverse effects in treatment. Another important tool to improve adherence is to enhance health education for patients and their families, and to carefully explain the possible adverse effects of the medications used in order to obtain the cooperation of patients and families in the maintenance of treatment.
Treatment facilitation programs to improve the transition to depression in the elderly
Sirey et al. reported that the use of a treatment-initiated program (TIP) intervention reduced the severity of depression and improved adherence to treatment in older patients with depression.
TIP is an individualized early intervention that targets depression and attitudes toward treatment in older patients to reduce barriers to treatment and enable adherence.
Fifty-two eligible elderly patients with depression were randomized to two groups, receiving conventional medication and medication combined with the TIP intervention (three 30-minute sessions at the first 6 weeks of treatment, and two telephone follow-up visits at weeks 8 and 10). The effect of the intervention on patients’ depressive symptoms was assessed with the HAM-D at enrollment and at weeks 6, 12, and 24 of treatment.
Results showed a significant improvement in depressive symptoms in the intervention group compared to the non-intervention group (p=0.005). At the end of the study, 71% of patients in the intervention group achieved remission compared to 42% in the non-intervention group (P=0.04).
At weeks 12 and 24 of treatment, more patients in the intervention group adhered to treatment than in the non-intervention group (P=0.05 at week 12; P=0.04 at week 24).