Presentation on theme: "The Neurobiology of Deliberate Self-Injury Sarah Swannell BSocSc(Hons)Psych Senior Research Technician Discipline of Psychiatry The University of Queensland."— Presentation transcript:
The Neurobiology of Deliberate Self-Injury Sarah Swannell BSocSc(Hons)Psych Senior Research Technician Discipline of Psychiatry The University of Queensland
What is deliberate self-injury? Deliberate destruction or alteration of body tissue without suicidal intent (Favazza, 1989) & done to relieve an undesirable emotional or psychological state Low lethality & low intent to die Repetitive Borderline Personality Disorder PTSD, depression, bi-polar disorder, schizophrenia, antisocial personality disorder
Prevalence 60% of psychiatric patients 40% of high school students and university students
Why do people self-injure? to feel better –release tension –stop dissociating –turning emotional pain into physical pain which is easier to handle –avoiding suicide
but how does self-injury make some people feel better? what happens in the brain when people self-injure?
The 5 phases of self-injury 1.Perception of threat unwanted negative emotion (desire to terminate it) 2.Choice of coping technique 3.Self-injury 4.Unknown mechanism of action 5.Objective and subjective tension relief
Vulnerabilities to experiencing unwanted negative emotion more intense negative emotions longer lasting negative emotions BPD & PTSD studies –the Hypothalamic-Pituitary-Adrenal Axis (HPA) axis is more sensitive (Yehuda et al., 2001) –History of trauma
PHASE 2. Choice of coping technique Serotonin system Prefrontal cortex-limbic system connection Prior learning Beliefs
Serotonin System Impulsivity & aggression –Low levels of 5-HIAA in CSF of depressed suicide attempters (Asberg et al., 1976) –Reduced levels of 5-HIAA in male borderlines (Brown et al., 1982) –Low serotonin correlated with suicide attempts, assaultiveness, instability, aggression & impulsiveness (Coccaro et al., 1989; Markowitz et al., 1995) –Self-mutilators had more personality pathology, greater lifetime aggression, more antisocial behaviour, and lower levels of serotonin activity (Simeon et al., 1992)
Post-mortem studies of suicides found fewer presynaptic serotonin transporter sites in ventromedial prefrontal cortex, hypothalamus, occipital lobe, brainstem (Mann, 1998) Peer-reared monkeys have lower serotonergic activity in comparison to maternally raised monkeys (Higley et al., 1993) Adverse rearing sets serotonergic functioning at a lower level (Mann, 2003)
Prefrontal cortex-limbic system connection Emotion dysregulation via: dysfunctional transmission between prefrontal cortex and limbic system (amygdala/anterior cingulate are under inhibitory control of the prefrontal cortex) –dorsolateral prefrontal cortex (PFC) is implicated in effortful regulation of affect –the orbitofrontal cortex, middle temporal gyrus, cingulate cortex, and the caudate nucleus are implicated in the identification and production of affect (Ramel, 2005). The ventromedial prefrontal cortex has been widely implicated in impulse regulation (Potenza, Leung, Blumberg, Peterson, Fulbright, Lacadie, Skudlarski & Gore, 2003; Fukui, Murai, Fukuyama, Hayashi,& Hanakawa, 2005).
Prior Learning Observation, accident Lack of physical pain Beliefs Action is needed to reduce unpleasant feelings Self-injury is acceptable My body and self is disgusting and deserving of punishment Overt action is needed to communicate feelings to others I must control my body and myself
PHASE 3. Self-injury Noxious stimuli depolarize nociceptors & signals dorsal root ganglia dorsal horns in spinal cord –a) projection neurons sensory info to brain –b) local excitatory & inhibitory interneurons to brain & regulate flow of info to brain Noxious stimuli travel up the spinal cord via anterolateral pathways and transmitted contralaterally to the brain. Chemical signals arrive at thalamus, periaqueductal grey matter, primary sensory cortex and associated cortices, reticular formation, medulla, pons, midbrain, hypothalamus, and caudal anterior cingulate cortex (Ploghaus et al., 1999). normally this results in subjective pain
Endogenous opioid system Approx 60% feel no pain (Bohus et al., 2000; Russ et al., 1993) Abuse/neglect/trauma can alter EOS & reduce sensitivity to pain (Kirmayer et al., 1987; van der Kolk, 1989; Dubo et al., 1997; van der Kolk et al., 1991) Decrease in pain sensitivity following early traumatic experiences has been reported in both animal and human studies (Russ et al., 1993)
In sample of BPD cutters, highest opioid levels correlated with recency and severity of cutting (Coid et al., 1983) Plasma opioid levels were higher in BPD patients who had SIB without pain compared to normals (Simeon et al., 2001).
PHASE 4. Unknown action
Noxious stimuli from tissue damage Spinal cord Sensory cortex Limbic system (amygdala)