To conclude, neurological patients require special attention from clinicians which should consist of openly verbalizing and exploring the suicidal thematic, inquiring about protective and risk factors, and promptly initiating both a psychopharmacological treatment and, where possible, psychological support. At the confluence of neurobiology and hopelessness, frequent psychiatric co-morbidities may play a primary role. This may ultimately cause a slip into the experience of an absurd condition. The latter may originate in, particularly for the most severe neurological diseases, the absence of curative treatments, unpredictable disease progression that leads to acute relapses or chronicity, a decrease of autonomy or self-identity, progressive social isolation, a sense of becoming useless, and a perception of feeling stigmatized. Often, in fact, they are accompanied by severe hopelessness. On the other hand, they question some subjective experiences of neurological patients, up to near existential positions. On the one hand, neurological diseases imply strictly biological impairments that are postulated to be the basis of vulnerability to suicide or result in the need for treatments for which a suicidal risk has been hypothesized. They also represent a paradigmatic arena to study the etio-pathogenic mechanisms underlying suicidality because they are emblematic of the heterogeneity and complexity of mutual interrelationships characterizing this issue. Neurological diseases expose individuals to a higher risk of suicidal ideation and suicidal behavior, including completed suicides and suicide attempts. As neuroimaging studies give more arguments to the mechanisms of these symptoms, they also stimulate research for a better individualization of specific affective dimensions in Parkinson's disease. Some of these deficits may be also related with a more pronounced reduction in striatal dopamine transmission. Apathy has received less attention, but has been related with gray matter volume reductions or functional deficits in many regions, as anterior and posterior cingulate and dorsolateral or inferior frontal gyrus. Depression in PD has been specifically associated with morphological and functional changes in prefrontal cortex, cingulate and thalamus, as with 5-HT transmission reduction in posterior cingulated and amygdala-hippocampus complex. Recent neuroimaging studies have provided specific findings related with these symptoms. Apathy and depression are considered among the most frequent ones, and have a negative impact on global functioning and quality of life.
Though the core symptoms of Parkinson's disease (PD) are motor-related, a majority of patients also have neuropsychiatric symptoms concerning mood, behavior and cognition.