The aetiological diagnosis of dementia in the elderly is dominated by the search for curable organic factors. With the exception of drug-induced disorders the treatment of organic factors only seldom leads to reversal of the dementia syndrome. On the other hand, approximately 10% of all dementia syndromes in the elderly are due to psychiatric conditions, most often affective and psychotic disorders. The main differential diagnosis is with a degenerative disease. Thus, a false diagnosis may have tremendous consequences. The diagnosis of a degenerative dementia suggests a universally serious prognosis for both the patient and their family. The diagnosis of a dementia syndrome due to a psychiatric disorder implies specific pharmacological and nonpharmacological interventions and is accompanied by a different and clearly more favorable prognosis than degenerative disorders. The clinical vignettes presented in this article help discuss the clinical features of the dementia syndromes due to psychiatric disorders and are intended to draw the GP's attention to the psychiatric aetiology in some demented patients