Human subjective homologues of established basic emotion correlations in lower mammals: a neuro-psychoanalytic study

Early separation experiences predispose people to depression and depressive episodes are triggered by experiences of social loss. The normal separation response entails a 'protest' phase followed by a 'despair' phase. The affective neuroscience paradigm of Jaak Panksepp identifies two basic emotion systems as being centrally involved in this normal separation response, namely, PANIC/GRIEF and SEEKING, and it conceptualises the despair phase of the cascade as the normal prototype for depression. In affective terms, major depression is seen as a disorder characterised by an overactive PANIC/GRIEF system and an underactive SEEKING system. There is considerable pre-clinical research that underwrites this conclusion, but the evidence in humans is limited. The general aim of this thesis was to investigate the claim that the feelings associated with depression represent an abnormal variant of the normal mammalian separation response in human subjects. The PANIC/GRIEF and SEEKING systems were artificially stimulated and dampened in a sample of healthy volunteers (N=16) via the administration of opioid and dopamine antagonists and agonists. This was an exploratory study, with a double-blind, placebo-controlled, repeated-measures design. The effects of the medications on SEEKING, PANIC/GRIEF, positive and negative affect and mood were investigated using both quantitative and qualitative measures. The results provided suggestive rather than strongly confirmatory evidence for the central hypotheses of this study. Naltrexone (a mu-opioid antagonist) did not increase PANIC/GRIEF and negative affect as predicted but there was some evidence that it led to the worsening of mood, a significant reduction in positive affect and feelings of social and affective disconnection. Morphine (a mu-opioid agonist) reduced PANIC/GRIEF as predicted, but contrary to predictions, positive affect was reduced. There was some evidence to show that Morphine led to an increase in the expression of feelings of contentment, relaxation, happiness and ...