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.