This is defined as any condition which mimics dementia. The commonest psychiatric disorder which mimics dementia is depression in which the retardation can be confused with the apathy of dementia. The guiding principle is careful clinical assessment and, if in doubt, a trial of an appropriate antidepressant.
A disturbance in the sleep pattern is a common symptom of depression but changes in the sleep pattern also occur as a consequence of ageing. Once depression has been diagnosed, there are several types of antidepressants which may be given. Because of their potent anticholinergic side effects, there seems little merit in prescribing the older tricyclic antidepressants (e.g. amitriptyline, imipramine) to such patients. There is now sufficient evidence to suggest that sedative antidepressants such as mianserin or trazodone given at night reduce the likelihood that the patient will require a sedative hypnotic. For the more retarded elderly patient, a non-sedative antidepressant such as lofepramine or one of the SSRIs (e.g. fluoxetine, fluvoxamine or sertraline) may be used.
The side effects and cardiotoxicity of the tricyclic antidepressants have been discussed in detail elsewhere in this volume and, while there is ample evidence of their therapeutic efficacy, it seems difficult to justify their use, particularly in a group of patients who are most vulnerable to their detrimental side effects. Of the newer antidepressants, the reversible inhibitors of monoamine oxidase type A such as moclobemide may also be of value in the elderly depressed patient, particularly in those patients who fail to respond to the amine uptake inhibitor type of antidepressant.
The safety of antidepressants should be the first priority for the elderly. For this reason, the second-generation antidepressants, or the atypical tricyclic antidepressant lofepramine, should be the drugs of choice. Undoubtedly the SSRI antidepressants have a major role to play and of these, citalopram and fluvoxamine have been extensively studied in the elderly depressed patient.
The pharmacological properties of the antidepressants has been extensively covered in Chapter 7. It should also be remembered that electroconvulsive therapy (ECT) can be potentially life-saving in the elderly, particularly if the patient is suffering from delusions or is retarded and depressed. ECT should also be considered when antidepressant drug treatment has failed.
A variety of psychotic conditions occur in the elderly, but it is important to remember that an elderly person who develops agitation, paranoid ideation or delusions may be suffering from a drug-induced delirium. The most common causes of such a condition are drugs that have potent central muscarinic-blocking properties, such as the antiparkinsonian agents, antihistamines, tricyclic antidepressants and antipsychotics. Withholding all psychotropic drug medication for a few days may be the most judicious management for this type of toxic psychosis.
Agitation and aggression are often symptoms of advanced Alzheimer's disease and high potency atypical antipsychotics such as risperidone or olanzapine may be of value in demented patients. Drugs such as chlorpromazine and thioridazine are more likely to produce hypotension, cardiac abnormalities and excessive sedation in the elderly patient, and side effects are, of course, a problem with the high potency neuroleptics in the elderly; centrally acting anticholinergic agents that are used to reverse some of the symptoms of parkinsonism in such patients should be used as little as possible and in the lowest possible doses.
Mania can occur in any age group. Acute manic episodes in the elderly may best be managed with high potency neuroleptics. The use of lithium is not contraindicated in the elderly provided renal clearance is reasonably normal. The dose administered should be carefully monitored, as the halflife of the drug is increased in the elderly to 36-48 hours in comparison to about 24 hours in the young adult. The serum lithium concentration in the elderly should be maintained at about 0.5mEq/litre. It is essential to ensure that the elderly patient is not on a salt-restricted diet before starting lithium therapy. The side effects and toxicity of lithium have been discussed in detail elsewhere (see p. 198 et seq.), and, apart from an increase in the frequency of confusional states in the elderly patient, the same adverse effects can be expected as in the younger patient.
DSM-IV has abandoned the terms paranoia and paraphrenia and replaced them with the term delusional disorder to describe non-affective and nonbizarre delusional states.
Neuroleptics have been the group of drugs most widely recommended for delusional states. Of the first-generation neuroleptics, the sedative, cognitive impairing and extrapyramidal side effects are likely to be particularly prominent in the elderly. The introduction of the atypical neuroleptics should improve the treatment of these disorders as they are generally better tolerated due to their improved side-effect profile.
TCAs, together with neuroleptics should be avoided as they may aggravate psychotic symptoms and potentiate any anticholinergic side effects. In the case of the very aggressive patient, parenteral administration of lorazepam or diazepam will usually be sufficient to enable the patient to be managed.
Anxiety states are often expressed somatically in the elderly and therefore it is important to exclude any physical disorder, such as cerebrovascular disease and thyroid dysfunction, which can be associated with apprehension and agitation.
Most psychotropic drugs are highly lipophilic, and the increased fat to lean body mass ratio and the decreased metabolism and excretion in the elderly patient mean that the half-lives of most psychotropic drugs are increased. The benzodiazepine anxiolytics and hypnotics are no exception. Following a single dose of chlordiazepoxide, diazepam or flurazepam, the time for elimination of the parent compounds and their active metabolites can be as long as 72 hours. For this reason, it is now general practice to administer a short-acting benzodiazepine (e.g. oxazepam, alprazolam or temazepam) only as needed and for as short a period as possible. Such drugs should only be used for a period not exceeding 6 weeks. Supportive psychotherapy, either as an adjunct to drug therapy or as an alternative, has an important role to play in treating mild anxiety states in the elderly.
Insomnia is a common complaint in the elderly. As people age they require less sleep, and a variety of physical ailments to which the elderly are subject can cause a change in the sleep pattern (e.g. cerebral atherosclerosis, heart disease, decreased pulmonary function), as can depression. Providing sedative hypnotics are warranted, the judicious use of short half-life benzodiazepines such as temazepam, triazolam, oxazepam and alprazolam for a period not exceeding 1-2 months may be appropriate. Because of their side effects, there would appear to be little merit in using chloral hydrate or related drugs in the treatment of insomnia in the elderly. It should be noted that even benzodiazepines which have a relatively short half-life are likely to cause excessive day-time sedation. The side effects and dependence potential of the anxiolytics and sedative hypnotics have been covered elsewhere in this volume (Chapter 9).
In addition to the benzodiazepines, there may be a role for the non-benzodiazepine drugs such as zalaplon, zolpidem or zopiclone in the treatment of anxiety and insomnia in the elderly. These drugs appear to be well tolerated in younger populations of patients, but it is essential to await the outcome of properly conducted trials of these drugs on a substantial number of elderly patients before any conclusions may be drawn regarding their value as alternatives to the benzodiazepines.
In SUMMARY, it can be seen that the types of psychotropic drug medication that may be used in the elderly are essentially similar to those used in the younger adult patient. The main difference lies in the reduction in distribution, metabolism and elimination of the drugs, which necessitates their administration in lower doses initially followed by a slower escalation of the dose until optimal benefit is obtained. Side effects, particularly anticholinergic effects, are more pronounced in the elderly and can contribute to poor compliance. Clearly the use of the older psychotropic medications, such as the tricyclic antidepressants and typical neuroleptics, should be avoided in elderly patients whenever possible and due consideration given to the second-generation antidepressants and antipsychotics. It is essential to emphasize that the side effects of psychotropic drugs, particularly the sedative and anticholinergic effects, are usually more pronounced in the elderly than in the younger patient.
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