Symptoms of Attenuated Psychosis Syndrome in Relatives of Clinical High-Risk Youth: Preliminary Evidence

BACKGROUND AND HYPOTHESIS

Attenuated Psychosis Syndrome (APS) impacts functioning and predicts increased risk of psychosis. Risk for developing APS itself has received minimal attention. Knowledge of familial and environmental contributions to APS symptoms would advance understanding of APS and risk for psychosis. As an initial step, this report presents the first data on APS symptoms in family members of APS patients.

STUDY DESIGN

This study utilized a discordant sibling-pair family study design. The Structured Interview for Psychosis-risk Syndromes (SIPS) was administered to 17 APS probands and 26 non-APS biological siblings. Probands and siblings were compared on positive, negative, disorganized, and general SIPS symptom scales and factors derived from those scales.

STUDY RESULTS

There was significantly greater symptom severity in probands compared to siblings on nine of 19 SIPS scales. Negative/anxiety, functioning, and positive symptom factors were identified. Probands showed significantly greater severity than siblings on the negative/anxiety and positive factors. Elevated pathology on the negative/anxiety factor best differentiated between probands and siblings, over and above the contribution of the positive factor. No difference was found for the functioning factor.

CONCLUSIONS

Results support the importance of non-familial effects on risk for APS and suggest differences in familial contribution to APS symptoms. Understanding the relative contribution of familial and environmental effects on APS symptoms may reveal important differences among APS patients, with implications for risk characterization, symptom course, and treatment selection.

Striatal dopamine synthesis and cognitive flexibility differ between hormonal contraceptive users and nonusers

In rodents and nonhuman primates, sex hormones are powerful modulators of dopamine (DA) neurotransmission. Yet less is known about hormonal regulation of the DA system in the human brain. Using positron emission tomography (PET), we address this gap by comparing hormonal contraceptive users and nonusers across multiple aspects of DA function: DA synthesis capacity via the PET radioligand 6-[18F]fluoro-m-tyrosine ([18F]FMT), baseline D2/3 receptor binding potential using [11C]raclopride, and DA release using methylphenidate-paired [11C]raclopride. Participants consisted of 36 healthy women (n = 15 hormonal contraceptive users; n = 21 naturally cycling/non users of hormonal contraception), and men (n = 20) as a comparison group. A behavioral index of cognitive flexibility was assessed prior to PET imaging. Hormonal contraceptive users exhibited greater DA synthesis capacity than NC participants, particularly in dorsal caudate, and greater cognitive flexibility. Furthermore, across individuals, the magnitude of striatal DA synthesis capacity was associated with cognitive flexibility. No group differences were observed in D2/3 receptor binding or DA release. Analyses by sex alone may obscure underlying differences in DA synthesis tied to women's hormone status. Hormonal contraception (in the form of pill, shot, implant, ring, or intrauterine device) is used by ~400 million women worldwide, yet few studies have examined whether chronic hormonal manipulations impact basic properties of the DA system. Findings from this study begin to address this critical gap in women's health.

Modulation of ventromedial orbitofrontal cortical glutamatergic activity affects the explore-exploit balance and influences value-based decision-making

The balance between exploration and exploitation is essential for decision-making. The present study investigated the role of ventromedial orbitofrontal cortex (vmOFC) glutamate neurons in mediating value-based decision-making by first using optogenetics to manipulate vmOFC glutamate activity in rats during a probabilistic reversal learning (PRL) task. Rats that received vmOFC activation during informative feedback completed fewer reversals and exhibited reduced reward sensitivity relative to rats. Analysis with a Q-learning computational model revealed that increased vmOFC activity did not affect the learning rate but instead promoted maladaptive exploration. By contrast, vmOFC inhibition increased the number of completed reversals and increased exploitative behavior. In a separate group of animals, calcium activity of vmOFC glutamate neurons was recorded using fiber photometry. Complementing our results above, we found that suppression of vmOFC activity during the latter part of rewarded trials was associated with improved PRL performance, greater win-stay responding and selecting the correct choice on the next trial. These data demonstrate that excessive vmOFC activity during reward feedback disrupted value-based decision-making by increasing the maladaptive exploration of lower-valued options. Our findings support the premise that pharmacological interventions that normalize aberrant vmOFC glutamate activity during reward feedback processing may attenuate deficits in value-based decision-making.