Neuropharmacology of the neuropsychiatric symptoms of dementia: possible targets for novel therapeutic approaches

Ageing of the world population makes of dementia a challenge for health systems worldwide. The cognitive disturbance is a serious but not the only issue in dementia; behavioural and psychological syndromes known as neuropsychiatric or behavioural and psychological symptoms of dementia remarkably reduce the quality of life of patients. Rising evidence is unraveling the pathophysiology of these symptoms in which all the neurotransmitter systems in the Central Nervous System (CNS) are implicated, with a pivotal role of alterations of the glutamatergic neurotransmission. Pharmacological agents for the treatment of these disorders endowed with efficacy and safety are not available yet; aromatherapy provides the best evidence in the control of agitation, the most resistant symptom. Basic research effort demonstrates that the essential oil of bergamot induces anxyolitic-like effects, devoid of sedation, typical of benzodiazepines, with noteworthy advantage for demented patients. People suffering from dementia often cannot verbalize pain, thus resulting unrelieved and contributing to agitation. Bergamot essential oil provides extensive evidence of analgesic properties independent from the route of administration. Among other mechanisms, modulation of autophagy, a process involved in neuropathic pain, seems to be implicated in the analgesic activity of bergamot essential oil. These data, together with the reported safety profile form the rational basis for bergamot as a neurotherapeutic to be trialed for the control of behavioural and psychological symptoms of dementia.