Disinhibition syndromes, secondary mania and bipolar disorder in old age.

BACKGROUND The neurological literature concerning disinhibition syndromes and secondary mania has run in parallel to clinical reports of bipolar disorder in old age. METHODS A critical review was conducted of both the neurological and geriatric psychiatry literature in an attempt to integrate the two streams. RESULTS Disinhibition syndromes include lateralization to the right hemisphere and localization of lesions to the orbito-frontal and basotemporal cortex involving limbic and frontal connections (orbito-frontal circuit). Mania in old age is associated with late onset, heterogeneous neurological disorders and poor outcome. CONCLUSION Bipolar disorders in old age may be understood in the context of affective vulnerability influenced by a specific neurobiologic substrate. LIMITATIONS The clinical literature consists predominantly of small case series and anecdotal reports. CLINICAL RELEVANCE Improved understanding of these syndromes may elucidate the pathogenesis and etiology of bipolar disorders and the neuropsychiatric syndromes affecting mood, motivation and behavioural disinhibition.