Elusive hypersomnolence in seasonal affective disorder: actigraphic and self-reported sleep in and out of depressive episodes.

BACKGROUND: Hypersomnolence has been considered a prominent feature of seasonal affective disorder (SAD) despite mixed research findings. In the largest multi-season study conducted to date, we aimed to clarify the nature and extent of hypersomnolence in SAD using multiple measurements during winter depressive episodes and summer remission. METHODS: Sleep measurements assessed in individuals with SAD and nonseasonal, never-depressed controls included actigraphy, daily sleep diaries, retrospective self-report questionnaires, and self-reported hypersomnia assessed via clinical interviews. To characterize hypersomnolence in SAD we (1) compared sleep between diagnostic groups and seasons, (2) examined correlates of self-reported hypersomnia in SAD, and (3) assessed agreement between commonly used measurement modalities. RESULTS: In winter compared to summer, individuals with SAD (n = 64) reported sleeping 72 min longer based on clinical interviews (p < 0.001) and 23 min longer based on actigraphy (p = 0.011). Controls (n = 80) did not differ across seasons. There were no seasonal or group differences on total sleep time when assessed by sleep diaries or retrospective self-reports (p's > 0.05). Endorsement of winter hypersomnia in SAD participants was predicted by greater fatigue, total sleep time, time in bed, naps, and later sleep midpoints (p's < 0.05). CONCLUSION: Despite a winter increase in total sleep time and year-round elevated daytime sleepiness, the average total sleep time (7 h) suggest hypersomnolence is a poor characterization of SAD. Importantly, self-reported hypersomnia captures multiple sleep disruptions, not solely lengthened sleep duration. We recommend using a multimodal assessment of hypersomnolence in mood disorders prior to sleep intervention.

Photoperiod is associated with hippocampal volume in a large community sample.

Although animal research has demonstrated seasonal changes in hippocampal volume, reflecting seasonal neuroplasticity, seasonal differences in human hippocampal volume have yet to be documented. Hippocampal volume has also been linked to depressed mood, a seasonally varying phenotype. Therefore, we hypothesized that seasonal differences in day-length (i.e., photoperiod) would predict differences in hippocampal volume, and that this association would be linked to low mood. Healthy participants aged 30-54 (M=43; SD=7.32) from the University of Pittsburgh Adult Health and Behavior II project (n=404; 53% female) were scanned in a 3T MRI scanner. Hippocampal volumes were determined using an automated segmentation algorithm using FreeSurfer. A mediation model tested whether hippocampal volume mediated the relationship between photoperiod and mood. Secondary analyses included seasonally fluctuating variables (i.e., sleep and physical activity) which have been shown to influence hippocampal volume. Shorter photoperiods were significantly associated with higher BDI scores (R(2)=0.01, ß=-0.12, P=0.02) and smaller hippocampal volumes (R(2)=0.40, ß=0.08, P=0.04). However, due to the lack of an association between hippocampal volume and Beck Depression Inventory scores in the current sample, the mediation hypothesis was not supported. This study is the first to demonstrate an association between season and hippocampal volume. These data offer preliminary evidence that human hippocampal plasticity could be associated with photoperiod and indicates a need for longitudinal studies.

Variants of SLC6A4 in depression risk following severe TBI.

BACKGROUND: Post-traumatic depression (PTD) may be a result of several factors like secondary injury chemical cascades as well as psycho-social factors following traumatic brain injury (TBI). While the role of serotonin in the pathology and treatment of idiopathic major depression may be somewhat controversial, it is unclear what role serotonin may play in PTD following a TBI. OBJECTIVE: To assess serotonergic function and genetic risk for PTD development over 1 year following TBI. RESEARCH DESIGN: Examination of variation in the serotonin transporter gene [SLC6A4 (5-HTTLPR, rs25331, and a variable number of tandem repeats variant in Intron 2)] in 109 subjects with moderate-severe injury. Depression was assessed using the Patient Health Questionnaire (PHQ-9) at 6 and/or 12 months post-injury. MAIN OUTCOMES AND RESULTS: At 6 months post-injury, subjects with a history of pre-morbid mood disorders and 5-HTTLPR L-homozygotes were at greater risk for PTD. Contrary to major depression, subjects without pre-morbid mood disorders (n = 80) and S-carriers were 2.803-times less likely to be depressed compared to L-homozygotes. At 12 months post-injury, LG-carriers were also less likely to experience PTD. Temporal analysis also showed 5-HTTLPR associations in PTD development across recovery. CONCLUSIONS: This study suggests a unique injury- and temporally-specific interaction between TBI and genetic risk for depression.

Sleep and Pain in Veterans with Chronic Pain: Effects of Psychological Pain Treatment and Temporal Associations.

Introduction: Chronic pain is highly prevalent in US military Veterans. Non-opioid and non-pharmacologic treatments are recommended when clinically appropriate, but research on the mechanisms underlying benefits of these treatments is lacking. Here, we examined the role of sleep in the effects of three non-pharmacologic pain treatments in Veterans. Specifically, we investigated whether treatment effects on sleep predicted treatment effects on pain occurring later, or vice versa. Methods: Veterans enrolled in a randomized controlled trial were invited to participate in this supplementary sleep study. A total of 174 Veterans were randomized to one of three 8-session, in-person, group-based pain treatments: hypnosis, mindfulness meditation, or education control. Measurements included self-reported sleep disturbance, pain intensity, and pain catastrophizing; sleep duration was assessed with actigraphy. Sleep and pain measurements were obtained at baseline, posttreatment, and 3-month posttreatment follow-up. Results: At baseline, average pain intensity was moderate (mean ± SD: 5.7 ± 1.7 on the 0-10 Numeric Rating Scale), pain catastrophizing was just below the clinically relevant threshold (mean ± SD: 28.6 ± 12.2 on the Pain Catastrophizing Scale), and subjective sleep disturbance exceeded the US population average (mean ± SD: 58.5 ± 8.1 on the Patient Reported Outcomes Measurement Information System Sleep Disturbance - Short Form). By contrast, objective sleep duration was consistent with the recommended daily sleep amount of 7-8 h for adults (mean ± SD: 8.3 ± 1.4 h). Across treatment conditions, pain intensity, pain catastrophizing, and subjective sleep disturbance were significantly less at posttreatment and 3-month follow-up than at baseline (p < 0.001). Actigraphic sleep duration did not differ significantly as a function of time. There was a high degree of covariation among the measures of pain intensity, pain catastrophizing, and sleep disturbance (p < 0.05). However, self-reported sleep disturbance was not significantly correlated with actigraphic sleep duration (|r| <= 0.13, p > 0.05). Sleep and pain variables observed at prior assessments predicted these same variables at subsequent assessments. There was no significant evidence that changes in pain preceded changes in sleep or that changes in sleep preceded changes in pain (all p > 0.05). Discussion: For this study's Veterans, treatment-related changes in sleep and pain appeared to occur in parallel. The concomitant changes in sleep and pain suggest that therapies improving pain in Veterans may yield attendant benefits for the treatment of sleep, and possibly vice versa.

Association of KIBRA rs17070145 polymorphism and episodic memory in individuals with severe TBI.

BACKGROUND: Studies implicate single nucleotide polymorphism (SNP) rs17070145, a common T → C polymorphism on the KIBRA gene, in mediating differences in episodic memory. In healthy adults, T-allele carriers perform better than non-carriers on episodic memory measures. However, this association is reversed in adults with subjective memory complaints and populations vulnerable to memory deficits, a problem common in traumatic brain injury (TBI). METHODS: This study assessed associations between variation in the KIBRA gene and cognitive function in 129 adults with severe TBI. In addition to other executive functioning and functional/global outcomes, the Buschke Selective Reminding Test (SRT), Rey-Osterrieth Complex Figure Test and California Verbal Learning Test-II (CVLT-II) were administered 6 and 12 months post-injury. RESULTS: T-allele non-carriers performed better than carriers on multiple episodic memory measures. At 6 months, T-allele non-carriers performed better for delayed recall measures on the SRT. At 12 months, T-allele non-carriers performed better on multiple SRT measures and on List-B learning with CVLT-II. No associations occurred with executive function or global outcome measures. CONCLUSION: These results suggest that rs17070145 T-allele effects are specific to episodic memory and support the hypothesis that associations between rs17070145 variation and memory are disparate between healthy and impaired populations.

Understanding the rehabilitation psychology specialty career pathway.

OBJECTIVE: Little is known about how psychologists choose their specialty practice area, and rehabilitation psychology is no exception. Specialization and specialty certification in professional psychology have been controversial topics impacting the field during the training sequence and across the span of professional careers (Drum & Blom, 2001; Robiner & Fossum, 2017). The American Board of Rehabilitation Psychology (ABRP) has been providing specialty certification since 1995 and rehabilitation psychology was recognized as a unique specialty in 2015 by the APA's Council for the Recognition of Specialties and Proficiencies in Professional Psychology (CRSPPP). There are limited established training programs and minimal information about the specialty in undergraduate course materials. The current survey is intended to provide information about how people are introduced to the field of rehabilitation psychology, specialty identification, and to identify opportunities for improvement. METHOD: A survey of members of APA Division 22 and ABRP specialists was conducted to collect information about their exposure to and involvement in rehabilitation psychology. RESULTS: Results from 174 respondents suggest that personal relationships are the current key means of recruitment and confirms that rehabilitation psychology has limited presence in undergraduate training. Most professionals come to identify with rehabilitation psychology after training in clinical neuropsychology and health psychology. CONCLUSIONS: These preliminary results suggest that the current generalist training sequence does not provide sufficient exposure to, or preparation for the field of rehabilitation psychology. Recruitment opportunities should emphasize student leadership network activities and the identification of early and midcareer practitioners unaware of the rehabilitation specialty. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

A Learning Health System Approach to Long COVID Care.

Background: Global initiatives to mitigate COVID-19 transmission have shifted health system priorities to management of patients with prolonged long COVID symptoms. To better meet the needs of patients, clinicians, and systems, a learning health system approach can use rapid-cycle methods to integrate data and real-world experience to iteratively evaluate and adapt models of long COVID care. Observations: Employees in the Veterans Health Administration formed a multidisciplinary workgroup. We sought to develop processes to learn more about this novel long COVID syndrome and innovative long COVID care models that can be applied within and outside of our health care system. We describe our workgroup processes and goals to create a mechanism for cross-facility communication, identify gaps in care and research, and cocreate knowledge on best practices for long COVID care delivery. Conclusions: The learning health system approach will be critical in reimagining health care service delivery after the COVID-19 pandemic.

Melanopsin-driven pupil response in summer and winter in unipolar seasonal affective disorder.

A retinal subsensitivity to environmental light may trigger Seasonal Affective Disorder (SAD) under low wintertime light conditions. The main aim of this study was to assess the responses of melanopsin-containing retinal ganglion cells in participants (N= 65) diagnosed with unipolar SAD compared to controls with no history of depression. Participants attended a summer visit, a winter visit, or both. Retinal responses to light were measured using the post-illumination pupil response (PIPR) to assess melanopsin-driven responses in the non-visual light input pathway. Linear mixed-effects modeling was used to test a group*season interaction on the Net PIPR (red minus blue light response, percent baseline). We observed a significant group*season interaction such that the PIPR decreased from summer to winter significantly in the SAD group while not in the control group. The SAD group PIPR was significantly lower in winter compared to controls but did not differ between groups in summer. Only 60% of the participants underwent an eye health exam, although all participants reported no history of retinal pathology, and eye exam status was neither associated with outcome nor different between groups. This seasonal variation in melanopsin driven non-visual responses to light may be a risk factor for SAD, and further highlights individual differences in responses to light for direct or indirect effects of light on mood.

APOE genetic associations with seizure development after severe traumatic brain injury.

PRIMARY OBJECTIVE: The purpose of the current study is to assess the role of the APOE genotype in post-traumatic seizure (PTS) development. RESEARCH DESIGN: A retrospective study of 322 adult Caucasians with a severe TBI and APOE genotype. METHODS AND PROCEDURES: Medical records were searched for PTS. Time to first seizure was categorized as early, late or delayed-onset PTS. Potential PTS associations by genotype, grouped genotype and allele were investigated. MAIN OUTCOME AND RESULTS: No statistically significant associations were found. However, two out of the four individuals (50%) with the E4/E4 genotype had late/delayed-onset PTS. Furthermore, none with a E2/E2 or E2/E4 genotype seized in the late periods. CONCLUSIONS: The results of this study may suggest 4/4 as a risk genotype for late/delayed onset PTS and a potential neuroprotective role of the E2 allele. However, this study did not definitively support a role for the APOE genotype in PTS susceptibility and indicates that larger populations are needed to fully evaluate the potential impact of APOE on PTS.

Sleepless in the hospital: A systematic review of non-pharmacological sleep interventions.

OBJECTIVE: Poor sleep is highly prevalent in inpatient medical settings and has been associated with attenuated healing and worsened outcomes following hospitalization. Although nonpharmacological interventions are preferred, little is known about the best way to intervene in hospital settings. METHOD: A systematic review of published literature examining nonpharmacological sleep interventions among inpatients in Embase, PsycINFO and PubMed in accordance with PRISMA guidelines. RESULTS: Forty-three of the 1529 originally identified manuscripts met inclusion criteria, encompassing 2713 hospitalized participants from 18 countries comprised of psychiatric and older adult patients living in hospital settings. Main outcomes were subjective and objective measures of sleep duration, quality, and insomnia. CONCLUSIONS: Overall, the review was unable to recommend any specific intervention due to the current state of the literature. The majority of included research was limited in quality due to lack of controls, lack of blinding, and reliance on self-reported outcomes. However, the literature suggests melatonin and CBT-I likely have the most promise to improve sleep in inpatient medical settings. Additionally, environmental modifications, including designated quiet time and ear plugs/eye masks, could be easily adopted in the care environment and may support sleep improvement. More rigorous research in nonpharmacological sleep interventions for hospitalized individuals is required to inform clinical recommendations.

Rest-activity rhythms characteristics and seasonal changes in seasonal affective disorder.

Identifying objectively measurable seasonal changes in 24-h activity patterns (rest-activity rhythms or RARs) that occur in seasonal affective disorder (SAD) could help guide research and practice towards new monitoring tools or prevention targets. We quantified RARs from actigraphy data using non-parametric and extended cosine based approaches, then compared RARs between people with SAD and healthy controls in the summer (n = 70) and winter seasons (n = 84). We also characterized the within-person seasonal RAR changes that occurred in the SAD (n = 19) and control (n = 26) participants who contributed repeated measures. Only controls had significant winter increases in RAR fragmentation (intra-daily variability; in controls mean winter-summer changes (log scale) = 0.05, 0.21 standard deviation, p = 0.03). In SAD participants only, estimated evening settling times (down-mesor) were an average of 30 min earlier in the winter compared with the summer (1-h standard deviation, p = 0.045). These RAR characteristics correlated with greater fatigue (Spearman r = 0.36) but not depression symptom severity. Additional research is needed to ascertain why healthy controls, but not people with SAD, appear to have increased RAR fragmentation in the winter. People with SAD lacked this increase in RAR fragmentation, and instead had earlier evening setting in the winter. Prospective and intervention studies with greater temporal resolution are warranted to ascertain how these seasonal behavioral differences relate to fatigue pathophysiology in SAD. Future research is needed to determine whether extending the winter active period, even in relatively fragmented bouts, could help reduce the fatigue symptoms common in SAD.

Alterations in emotion generation and regulation neurocircuitry in depression and eating disorders: A comparative review of structural and functional neuroimaging studies.

Major depression and eating disorders (EDs) are highly co-morbid and may share liability. Impaired emotion regulation may represent a common etiological or maintaining mechanism. Research has demonstrated that depressed individuals and individuals with EDs exhibit impaired emotion regulation, with these impairments being associated with changes in brain structure and function. The goal of this review was to evaluate findings from neuroimaging studies of depression and EDs to determine whether there are overlapping alterations in the brain regions known to be involved in emotion regulation, evidence of which would aid in the diagnosis and treatment of these conditions. Our review of the literature suggests that depression and EDs exhibit common structural and functional alterations in brain regions involved in emotion regulation, including the amygdala, ventral striatum and nucleus accumbens, anterior cingulate cortex, insula, and dorsolateral prefrontal cortex. We present preliminary support for a shared etiological mechanism. Future studies should consider manipulating emotion regulation in a sample of individuals with depression and EDs to better characterize abnormalities in these brain circuits.

Chronotype predicts positive affect rhythms measured by ecological momentary assessment.

Evening chronotype, a correlate of delayed circadian rhythms, is associated with depression. Altered positive affect (PA) rhythms may mediate the association between evening chronotype and depression severity. Consequently, a better understanding of the relationship between chronotype and PA may aid in understanding the etiology of depression. Recent studies have found that individuals with evening chronotype show delayed and blunted PA rhythms, although these studies are relatively limited in sample size, representativeness and number of daily affect measures. Further, published studies have not included how sleep timing changes on workday and non-workdays, or social jet lag (SJL) may contribute to the chronotype-PA rhythm link. Healthy non-depressed adults (n = 408) completed self-report affect and chronotype questionnaires. Subsequently, positive and negative affects were measured hourly while awake for at least two workdays and one non-workday by ecological momentary assessment (EMA). Sleep variables were collected via actigraphy and compared across chronotype groups. A cosinor variant of multilevel modeling was used to model individual and chronotype group rhythms and to calculate two variables: (1) amplitude of PA, or the absolute amount of daily variation from peak to trough during one period of the rhythm and (2) acrophase, or the time at which the peak amplitude of affect rhythms occurred. On workdays, individuals with evening chronotype had significantly lower PA amplitudes and later workday acrophase times than their morning type counterparts. In contrast to predictions, SJL was not found to be a mediator in the relationship between chronotype and PA rhythms. The association of chronotype and PA rhythms in healthy adults may suggest the importance of daily measurement of PA in depressed individuals and would be consistent with the hypothesis that evening chronotype may create vulnerability to depression via delayed and blunted PA rhythms.

COMT met allele differentially predicts risk versus severity of aberrant eating in a large community sample.

Prefrontal dopamine (DA) transmission participates in the reinforcement of reward-driven behaviors like eating. Because catechol-O-methyltransferase (COMT) degrades DA and is expressed in the prefrontal cortex, variation in the COMT gene may modulate eating behavior. Previous studies have shown that the met allele of the COMT val158met single nucleotide polymorphism (SNP) is associated with Bulimia Nervosa (BN). The specific aim of this study was to test whether the met allele increased risk for, and severity of, eating disorder symptomatology in community volunteers. Caucasian adults (N=1003; 51.2% female) from the University of Pittsburgh Adult Health and Behavior Project (AHAB) were genotyped and completed the Eating Disorders Inventory (EDI). Logistic and Poisson regression analyses assessed genotype-dependent presence and severity of eating disorder symptomatology. The met allele was significantly associated with the presence of symptoms on the Bulimia subscale and the severity of Body Dissatisfaction scores. All EDI subscales significantly predicted BMI. To our knowledge, these are the first data indicating that the COMT met allele increases risk for some symptoms of disordered eating, while increasing severity of others, in a community sample. These novel findings may have important implications for understanding the etiology of heterogeneous disordered eating phenotypes.

Melanopsin, photosensitive ganglion cells, and seasonal affective disorder.

In two recent reports, melanopsin gene variations were associated with seasonal affective disorder (SAD), and in changes in the timing of sleep and activity in healthy individuals. New studies have deepened our understanding of the retinohypothalamic tract, which translates environmental light received by the retina into neural signals sent to a set of nonvisual nuclei in the brain that are responsible for functions other than sight including circadian, neuroendocrine and neurobehavioral regulation. Because this pathway mediates seasonal changes in physiology, behavior, and mood, individual variations in the pathway may explain why approximately 1-2% of the North American population develops mood disorders with a seasonal pattern (i.e., Major Depressive and Bipolar Disorders with a seasonal pattern, also known as seasonal affective disorder/SAD). Components of depression including mood changes, sleep patterns, appetite, and cognitive performance can be affected by the biological and behavioral responses to light. Specifically, variations in the gene sequence for the retinal photopigment, melanopsin, may be responsible for significant increased risk for mood disorders with a seasonal pattern, and may do so by leading to changes in activity and sleep timing in winter. The retinal sensitivity of SAD is hypothesized to be decreased compared to controls, and that further decrements in winter light levels may combine to trigger depression in winter. Here we outline steps for new research to address the possible role of melanopsin in seasonal affective disorder including chromatic pupillometry designed to measure the sensitivity of melanopsin containing retinal ganglion cells.

Genetic variability in glutamic acid decarboxylase genes: associations with post-traumatic seizures after severe TBI.

Post traumatic seizures (PTS) occur frequently after traumatic brain injury (TBI). Since gamma-amino butyric acid (GABA) neurotransmission is central to excitotoxicity and seizure development across multiple models, we investigated how genetic variability for glutamic acid decarboxylase (GAD) influences risk for PTS. Using both a tagging and functional single nucleotide polymorphism (SNP) approach, we genotyped the GAD1 and GAD2 genes and linked them with PTS data, regarding time to first seizure, obtained for 257 adult subjects with severe TBI. No significant associations were found for GAD2. In the GAD1 gene, the tagging SNP (tSNP) rs3828275 was associated with an increased risk for PTS occurring <1 wk. The tSNP rs769391 and the functional SNP rs3791878 in the GAD1 gene were associated with increased PTS risk occurring 1 wk-6 mo post-injury. Both risk variants conferred an increased susceptibility to PTS compared to subjects with 0-1 risk variant. Also, those with haplotypes having both risk variants had a higher PTS risk 1 wk-6 mo post-injury than those without these haplotypes. Similarly, diplotype analysis showed those with 2 copies of the haplotype containing both risk alleles were at the highest PTS risk. These results implicate genetic variability within the GABA system in modulating the development of PTS.

Cognitive and behavioral predictors of light therapy use.

OBJECTIVE: Although light therapy is effective in the treatment of seasonal affective disorder (SAD) and other mood disorders, only 53-79% of individuals with SAD meet remission criteria after light therapy. Perhaps more importantly, only 12-41% of individuals with SAD continue to use the treatment even after a previous winter of successful treatment. METHOD: Participants completed surveys regarding (1) social, cognitive, and behavioral variables used to evaluate treatment adherence for other health-related issues, expectations and credibility of light therapy, (2) a depression symptoms scale, and (3) self-reported light therapy use. RESULTS: Individuals age 18 or older responded (n = 40), all reporting having been diagnosed with a mood disorder for which light therapy is indicated. Social support and self-efficacy scores were predictive of light therapy use (p's<.05). CONCLUSION: The findings suggest that testing social support and self-efficacy in a diagnosed patient population may identify factors related to the decision to use light therapy. Treatments that impact social support and self-efficacy may improve treatment response to light therapy in SAD.

Melanopsin gene variations interact with season to predict sleep onset and chronotype.

The human melanopsin gene has been reported to mediate risk for seasonal affective disorder (SAD), which is hypothesized to be caused by decreased photic input during winter when light levels fall below threshold, resulting in differences in circadian phase and/or sleep. However, it is unclear if melanopsin increases risk of SAD by causing differences in sleep or circadian phase, or if those differences are symptoms of the mood disorder. To determine if melanopsin sequence variations are associated with differences in sleep-wake behavior among those not suffering from a mood disorder, the authors tested associations between melanopsin gene polymorphisms and self-reported sleep timing (sleep onset and wake time) in a community sample (N = 234) of non-Hispanic Caucasian participants (age 30-54 yrs) with no history of psychological, neurological, or sleep disorders. The authors also tested the effect of melanopsin variations on differences in preferred sleep and activity timing (i.e., chronotype), which may reflect differences in circadian phase, sleep homeostasis, or both. Daylength on the day of assessment was measured and included in analyses. DNA samples were genotyped for melanopsin gene polymorphisms using fluorescence polarization. P10L genotype interacted with daylength to predict self-reported sleep onset (interaction p < .05). Specifically, sleep onset among those with the TT genotype was later in the day when individuals were assessed on longer days and earlier in the day on shorter days, whereas individuals in the other genotype groups (i.e., CC and CT) did not show this interaction effect. P10L genotype also interacted in an analogous way with daylength to predict self-reported morningness (interaction p < .05). These results suggest that the P10L TT genotype interacts with daylength to predispose individuals to vary in sleep onset and chronotype as a function of daylength, whereas other genotypes at P10L do not seem to have effects that vary by daylength. A better understanding of how melanopsin confers heightened responsivity to daylength may improve our understanding of a broad range of behavioral responses to light (i.e., circadian, sleep, mood) as well as the etiology of disorders with seasonal patterns of recurrence or exacerbation.

Adenosine A1 receptor gene variants associated with post-traumatic seizures after severe TBI.

Post-traumatic seizures (PTS) are a significant complication from traumatic brain injury (TBI). Adenosine, a major neuroprotective and neuroinhibitory molecule, is important in experimental epilepsy models. Thus, we investigated the adenosine A1 receptor (A1AR) gene and linked it with clinical data extracted for 206 subjects with severe TBI. Tagging SNPs rs3766553, rs903361, rs10920573, rs6701725, and rs17511192 were genotyped, and variant and haplotype associations with PTS were explored. We investigated further genotype, grouped genotype, and allelic associations with PTS for rs3766553 and rs10920573. Multivariate analysis of rs3766553 demonstrated an association between the AA genotype and increased early PTS incidence. In contrast, the GG genotype was associated with increased late and delayed-onset PTS rates. Multivariate analysis of rs10920573 revealed an association between the CT genotype and increased late PTS. Multiple risk genotype analysis showed subjects with both risk genotypes had a 46.7% chance of late PTS. To our knowledge, this is the first report implicating genetic variability in the A1AR with PTS, or any type of seizure disorder. These results provide a rationale for further studies investigating how adenosine neurotransmission impacts PTS, evaluating anticonvulsants in preventing and treating PTS, and developing and testing targeted adenosinergic therapies aimed at reducing PTS.