Other possible risk factors for very late-onset schizophrenia include sensory deficits, premorbid personality disorder, social isolation, neuropsychological abnormalities, and female gender.
Sensory deficits. Several studies have reported that hearing and vision loss is more prevalent in older patients with very late-onset schizophrenia than in similarly aged controls. Most of these studies have associated either auditory or sensory impairment with very late-onset schizophrenia,8 but most did not include appropriate controls.
One case-control study (of younger patients)8 found that only uncorrected sensory deficits were over-represented in late-onset cases. This finding implies that one should find out if the patient is willing or able to get medical help for the sensory deficit, as well as whether that treatment has been adequate, before calling the sensory deficit a sequela of late-onset schizophrenia.
Premorbid personality disorder. Patients with very late-onset schizophrenia are widely reported to have gone through life reclusive and paranoid.5 Of interest is that unlike many of their early-onset counterparts, late-onset patients tend to have achieved fairly well in the workplace. Whether this success reflects a later onset of illness cannot be determined.
Social isolation is common among older persons and even more so among those with very late-onset schizophrenia.9 Whether this finding reflects patients’ premorbid personalities, the illness itself, or a risk factor for the disorder is open to conjecture.
Neuropsychological abnormalities. Assessments of patients with very late-onset schizophrenia reveal cognitive impairment patterns similar to those reported in patients with an earlier onset10 but distinct from those reported in patients with psychosis associated with dementia. CTand MRIstudies reveal focal (reduced left temporal lobe volume) and nonspecific (increased ventricular-to-brain ratios) structural abnormalities similar to those in younger patients.11
Table 1
CLINICAL FEATURES OF SCHIZOPHRENIA: EARLY- VS. VERY LATE-ONSET TYPES
| Clinical feature | Early onset | Very late onset |
|---|---|---|
| Persecutory delusions | Common (often elaborate) | Common (often elaborate) |
| Partition delusions | Rare | Common |
| Negative symptoms | Common | Rare |
| Formal thought disorder | Common | Rare |
| Hallucinations | Common, especially auditory | Often prominent (can manifest in multiple modalities) |
| Gender differences | Equally common in men, women | More common in women |
| Family history of schizophrenia | Common | Less common |
| Uncorrected auditory, visual impairments | No consistent relationship | Common; excessive in some patients |
| Premorbid personality | Maybe schizoid/schizotypal | Reclusive, suspicious |
| Social abilities | Social isolation | Social isolation |
| Marital status | Usually unmarried | Usually unmarried |
| Cognitive deficits, structural brain abnormalities | Similar for both groups | Similar for both groups |
Researchers previously reported excessive white-matter abnormalities in late-onset patients compared with healthy controls—a consistent finding in patients with late-life depression. More recent studies that carefully excluded organic cerebral disorders have not replicated this finding, however.11
Female gender. Very late-onset schizophrenia is more common in women than in men.12 Female-to-male ratios ranging from 2.2:1 to 22.5:1 have been calculated. Although women generally live longer than men, this predominance is still greater than one would expect. It might also hide important clues regarding schizophrenia and related disorders across the life span, including the fact that the brains of men and women show sex-specific patterns of aging.12
Managing very late-onset schizophrenia
Initial assessment. Patients who present with a new-onset psychotic disorder at any age require careful evaluation to exclude an underlying organic cause. The following are strongly suggested in older patients with new-onset psychoses:
- comprehensive history (including medications)
- physical (including neurologic) examination
- laboratory investigations
- CTneuroimaging
- and cognitive screening, such as the Mini Mental State Examination.
Drug treatment. Despite the wealth of published data on the psychopharmacologic management of schizophrenia, few randomized, controlled trials have examined the use of drugs to treat the disorder’s very late-onset form. Case reports or small open studies comprise the available literature. Significant flaws in treatment studies have included diagnostic heterogeneity, mixing of early- and late-onset patients, inadequate outcome criteria, and lack of control groups.13
As with early-onset schizophrenia, however, antipsychotics appear to improve the acute symptoms of very late-onset schizophrenia and reduce the risk of relapse.14 Pearlson et al4 reported at least partial remission in 76% of patients with late-onset schizophrenia after neuroleptic regimens (complete remission occurred in 48%). The presence of thought disorder or a premorbid schizoid personality predicted poor response to treatment, whereas gender, family history, and first-rank symptoms (auditory hallucinations, delusions, social withdrawal) did not significantly affect outcome.
Very late-onset patients respond to about one-half the antipsychotic dosage required for younger patients.13 Sweet and Pollock15 found an average dosage of chlorpromazine equivalents, 148 mg/d, to be effective in older patients, compared with >300 mg/d in younger cohorts.
Neuroleptic side effects. Older patients are more susceptible than their younger counterparts to side effects and adverse reactions from typical neuroleptics, even at low dosages. Age-related differences in pharmacokinetics and pharmacodynamics, combined with the increased incidence of comorbid physical disease and polypharmacy among older patients, often complicate pharmacotherapy for late-onset schizophrenia.