Adult Attachment System Links With Brain Mu Opioid Receptor Availability In Vivo.

BACKGROUND: Secure attachment is important in maintaining an individual's health and well-being. Attachment disturbances increase the risk for developing psychiatric disorders such as affective disorders. Yet, the neurobiological correlates of human attachment are poorly understood at the neurotransmitter level. We investigated whether adult attachment style is linked to functioning of the opioid and serotonergic systems in the human brain. METHODS: We used positron emission tomography with radioligands [11C]carfentanil and [11C]MADAM to quantify mu opioid receptor (n = 39) and serotonin transporter (n = 37) availability in volunteers with no current psychiatric disorders. Attachment style was determined according to the Dynamic-Maturational Model of Attachment and Adaptation with the structured Adult Attachment Interview. RESULTS: Secure attachment was associated with higher mu opioid receptor availability in the hippocampus, amygdala, thalamus, and prefrontal cortex when compared with insecure (i.e., avoidant or ambivalent groups combined) attachment. In contrast, attachment style was not associated with serotonin transporter availability. CONCLUSIONS: Our results provide preliminary in vivo evidence that the opioid system may be involved in the neurocircuits associated with individual differences in adult attachment behavior. The results suggest that variation in mu opioid receptor availability may be linked with the individuals' social relationships and psychosocial well-being and thus contributes to risk for psychiatric morbidity.

Sex difference in brain CB1 receptor availability in man.

The endocannabinoid system (ECS) has a widespread neuromodulatory function in the central nervous system and is involved in important aspects of brain function including brain development, cortical rhythms, plasticity, reward, and stress sensitivity. Many of these effects are mediated via the cannabinoid CB1 receptor (CB1R) subtype. Animal studies convincingly show an interaction between the ECS and sex hormones, as well as a sex difference of higher brain CB1R in males. Human in vivo studies of sex difference have yielded discrepant findings. Gender differences in CB1R availability were investigated in vivo in 11 male and 11 female healthy volunteers using a specific CB1R tracer [18F]FMPEP-d2 and positron emission tomography (PET). Regional [18F]FMPEP-d2 distribution volume was used as a proxy for CB1R availability. In addition, we explored whether CB1R availability is linked to neuropsychological functioning. Relative to females, CB1R availability was on average 41% higher in males (p = 0.002) with a regionally specific effect larger in the posterior cingulate and retrosplenial cortices (p = 0.001). Inter-subject variability in CB1R availability was similar in both groups. Voxel-based analyses revealed an inverse association between CB1R availability and visuospatial working memory task performance in both groups (p < 0.001). A CB1R sex difference with a large effect size was observed and should be considered in the design of CB1R-related studies on neuropsychiatric disorders. The behavioural correlates and clinical significance of this difference remain to be further elucidated, but our studies suggest an association between CB1R availability and working memory.

Childhood trauma and premorbid adjustment among individuals at clinical high risk for psychosis and normal control subjects.

AIM: Traumatic childhood experiences are associated with psychotic illness and are frequently reported in patients at clinical high risk (CHR) for psychosis. Moreover, deteriorating premorbid functioning from childhood, and through adolescence, is related to greater severity of overall symptomatology and poorer outcomes in patients with psychosis. We studied the prevalence of traumatic childhood experiences and premorbid adjustment and their association with each other in patients at CHR for psychosis and normal control subjects (NCSs). METHODS: A total of 20 CHR patients for psychosis and 30 NCSs aged 14 to 35 participated in the present study. The CHR patients were identified as prodromal to psychosis using the Structured Interview for Prodromal Syndromes/Scale of Prodromal Symptoms. Premorbid adjustment was assessed by using the premorbid adjustment scale (PAS), and self-reported childhood trauma was assessed with the Trauma and Distress Scale (TADS). RESULTS: In CHR patients, TADS and PAS scores were higher than in NCSs. In CHR patients, TADS correlated significantly with the PAS general section and observably, but not significantly, with adolescence and adulthood sections. CONCLUSION: CHR patients reported more childhood trauma experiences and poorer premorbid adjustment than NCSs. In CHR patients, traumatic childhood experiences are associated with poor general premorbid adjustment.