Two experiments examined simple addition processes in adults in which single integer problems were presented for true-false verification. The stated sums of the false problems were incorrect by a reasonable (±1 or 2) or unreasonable (±4 or 5) amount from the correct sums. The reaction time (RT) to unreasonable wrong problems was significantly faster than to reasonable wrong, and RT to true problems was fastest overall. The best predictor of RT to true and reasonable false stimuli was the square of the correct sum; for the unreasonable false problems, the minimum addend accounted for most of the variance. A second experiment replicated the above effects and found facilitation of RT with immediately repeated stimuli. These results were judged inconsistent with strictly counting or retrieval-counting models of addition. Instead, the RT patterns supported a retrieval-decision model of addition in memory, and were interpreted as analogous to search and distance effects in semantic information processing.Our ability, as adults, to add single integers both rapidly and accurately is not matched by our ability, as cognitive psychologists, to account for this obviously common phenomenon. Recent experimental work by Banks (e.g., Banks, Fujii, & Kayra-Stuart, 1976) and others has provided insight into the processes of judging two numbers to be unequal. Shepard and his co-workers (Shepard, Kilpatric, & Cunningham, 1975) have performed extensive investigations into the structure of memory representations of numbers per se. Hayes (1973) has described several visual imagery strategies reported by subjects who are solving arithmetic problems of varying complexity. Despite this research activity, however, the most recent comprehensive treatment of simple addition in adults, by Groen and Parkman (1972), concludes that we remain far from an understanding of the basic processes involved in common arithmetic performance. The original pur-An earlier version of these results was presented at the Annual Meeting of the Psychonomic Society,

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Roughly 15 million of the 62 million rural U.S. residents struggle with mental illness and substance abuse. These rural dwellers have significant health care needs but commonly experience obstacles to obtaining adequate psychiatric services. Important but little-recognized ethical dilemmas also affect rural mental health care delivery. Six attributes of isolated settings with limited resources appear to intensify these ethical dilemmas: overlapping relationships, conflicting roles, and altered therapeutic boundaries between caregivers, patients, and families; challenges in preserving patient confidentiality; heightened cultural dimensions of mental health care; "generalist" care and multidisciplinary team issues; limited resources for consultation about clinical ethics; and greater stresses experienced by rural caregivers. The authors describe these features of rural mental health care and provide vignettes illustrating dilemmas encountered in the predominantly rural and frontier states of Alaska and New Mexico. They also outline constructive approaches to rural ethical dilemmas in mental health care.

Acute agitation occurs in a variety of medical and psychiatric conditions, and when severe can result in behavioural dyscontrol. Rapid tranquillisation is the assertive use of medication to calm severely agitated patients quickly, decrease dangerous behaviour and allow treatment of the underlying condition. Intramuscular injections of typical antipsychotics and benzodiazepines, given alone or in combination, have been the treatment of choice over the past few decades. Haloperidol and lorazepam are the most widely used agents for acute agitation, are effective in a wide diagnostic arena and can be used in medically compromised patients. Haloperidol can cause significant extrapyramidal symptoms, and has rarely been associated with cardiac arrhythmia and sudden death. Lorazepam can cause ataxia, sedation and has additive effects with other CNS depressant drugs.Recently, two fast-acting preparations of atypical antipsychotics, intramuscular ziprasidone and intramuscular olanzapine, have been developed for treatment of acute agitation. Intramuscular ziprasidone has shown significant calming effects emerging 30 minutes after administration for acutely agitated patients with schizophrenia and other nonspecific psychotic conditions. Intramuscular ziprasidone is well tolerated and has gained widespread use in psychiatric emergency services since its introduction in 2002. In comparison with other atypical antipsychotics, ziprasidone has a relatively greater propensity to increase the corrected QT (QTc) interval and, therefore, should not be used in patients with known QTc interval-associated conditions. Intramuscular olanzapine has shown faster onset of action, greater efficacy and fewer adverse effects than haloperidol or lorazepam in the treatment of acute agitation associated with schizophrenia, schizoaffective disorder, bipolar mania and dementia. Intramuscular olanzapine has been shown to have distinct calming versus nonspecific sedative effects. The recent reports of adverse events (including eight fatalities) associated with intramuscular olanzapine underscores the need to follow strict prescribing guidelines and avoid simultaneous use with other CNS depressants. Both intramuscular ziprasidone and intramuscular olanzapine have shown ease of transition to same-agent oral therapy once the episode of acute agitation has diminished. No randomised, controlled studies have examined either agent in patients with severe agitation, drug-induced states or significant medical comorbidity. Current clinical experience and one naturalistic study with intramuscular ziprasidone suggest that it is efficacious and can be safely used in such populations. These intramuscular atypical antipsychotics may represent a historical advance in the treatment of acute agitation.

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