Intense nihilism, somatization and agitation in old age are the hallmark symptoms of:

A i.e. Involutional Melancholia In old age presence of depression, delusions of sin, guilt, povey, persecution, intense nihilismQ, somatizationQ with marked agitation & dejectionQ ours diagnosis of involutional melanocholia.The key class specific feature of psychotic (delusional) depression is presence of psychotic features (eg delusion, hallucination); of melanocholia is psychomotor disturbance (i.e. impaired cognitive processing, motor retardation and agitation)Q; and of non melanocholic depression is depressed mood.Depression in increasing severity can be classified as - non melanocholic (neurotic & reactive), melancholic (endogenous) and psychotic (delusional) depression. It is impoant to note that features of less severe type are present (even with more severity) in more severe type of depression.For example endogeneity symptoms (paiculary non reactive mood, anhedonia & constipation) and psychomotor disturbance characteristic of melanocholic (endogenous) depression are frequently more severe in psychotic depression. So in psychotic depression patient tend to believe that their bowels have turned to concrete or they have a bowel cancer if they develop constipation. And very severe psychomotor disturbance may l/t impression of pseudodementia.Historically neurotic and reactive depression were used, with the former emphasizing a premorbid style of neuroticism & high anxiety, and the latter defining the depression developing largely in response to life event stressor.With current or most recent base diagnosis of major depression following feature specifier (subtypes) may be seen.