Consistent evidence indicates that exercise improves cognition and mood, with preliminary evidence suggesting that brain-derived neurotrophic factor (BDNF) may mediate these effects. The aim of the current meta-analysis was to provide an estimate of the strength of the association between exercise and increased BDNF levels in humans across multiple exercise paradigms. We conducted a meta-analysis of 29 studies (N = 1,111 participants) examining the effect of exercise on BDNF levels in three exercise paradigms: (1) a single session of exercise, (2) a session of exercise following a program of regular exercise, and (3) resting BDNF levels following a program of regular exercise. Moderators of this effect were also examined. Results demonstrated a moderate effect size for increases in BDNF following a single session of exercise (Hedges’ g = 0.46, p < 0.001). Further, regular exercise intensified the effect of a session of exercise on BDNF levels (Hedges’ g = 0.58, p = 0.02). Finally, results indicated a small effect of regular exercise on resting BDNF levels (Hedges’ g = 0.28, p = 0.005). When analyzing results across paradigms, sex significantly moderated the effect of exercise on BDNF levels, such that studies with more women showed less BDNF change resulting from exercise. Effect size analysis supports the role of exercise as a strategy for enhancing BDNF activity in humans, but indicates that the magnitude of these effects may be lower in females relative to males.
Objective Poor threat-safety discrimination reflects prefrontal cortex dysfunction in adult anxiety disorders. While adolescent anxiety disorders are impairing and predict high risk for adult anxiety disorders, no prior study examines neural correlates of threat-safety discrimination in this group. The current study compares prefrontal cortex function in anxious and healthy adolescents and adults following conditioning and extinction, processes requiring threat-safety learning. Method Anxious and healthy adolescents and adults (n=114) completed fear conditioning and extinction in the clinic. Conditioned stimuli (CS+) were neutral faces, paired with an aversive scream. Physiological and subjective data were acquired. Several weeks later, 82 participants viewed the CS+ and morphed images resembling the CS+ in a magnetic resonance imaging (MRI) scanner. During scanning, participants made difficult threat-safety discriminations while appraising threat and explicit memory of the CS+. Results During conditioning and extinction, anxious groups reported more fear than healthy groups, but patient groups did not differ on physiology. During imaging, both anxious adolescents and adults exhibited lower sub-genual anterior cingulate (sgACC) activation than healthy peers, specifically when appraising threat. In ventromedial prefrontal cortex (vmPFC), relative to their age-matched peer groups, anxious adults exhibited reduced activation when appraising threat, whereas anxious adolescents exhibited a U-shaped pattern of activation, with greater activation to the most extreme CS and CS−. Conclusions Two regions of the prefrontal cortex are involved in anxiety disorders. Reduced sgACC engagement is a shared feature in adult and adolescent anxiety disorders, but vmPFC dysfunction is age-specific. The unique U-shaped pattern of vmPFC activation in many anxious adolescents could reflect heightened sensitivity to threat and safety conditions. How variations in the pattern relate to later risk for adult illness remains to be determined.
ImportanceAnxiety disorders have a lifetime prevalence of approximately 34% in the US, are often chronic, and significantly impair quality of life and functioning.ObservationsAnxiety disorders are characterized by symptoms that include worry, social and performance fears, unexpected and/or triggered panic attacks, anticipatory anxiety, and avoidance behaviors. Generalized anxiety disorder (6.2% lifetime prevalence), social anxiety disorder (13% lifetime prevalence), and panic disorder (5.2% lifetime prevalence) with or without agoraphobia are common anxiety disorders seen in primary care. Anxiety disorders are associated with physical symptoms, such as palpitations, shortness of breath, and dizziness. Brief screening measures applied in primary care, such as the Generalized Anxiety Disorder–7, can aid in diagnosis of anxiety disorders (sensitivity, 57.6% to 93.9%; specificity, 61% to 97%). Providing information about symptoms, diagnosis, and evidence-based treatments is a first step in helping patients with anxiety. First-line treatments include pharmacotherapy and psychotherapy. Selective serotonin reuptake inhibitors (SSRIs, eg, sertraline) and serotonin-norepinephrine reuptake inhibitors (SNRIs, eg, venlafaxine extended release) remain first-line pharmacotherapy for generalized anxiety disorder, social anxiety disorder, and panic disorder. Meta-analyses suggest that SSRIs and SNRIs are associated with small to medium effect sizes compared with placebo (eg, generalized anxiety disorder: standardized mean difference [SMD], −0.55 [95% CI, −0.64 to −0.46]; social anxiety disorder: SMD, −0.67 [95% CI, −0.76 to −0.58]; panic disorder: SMD, −0.30 [95% CI, −0.37 to −0.23]). Cognitive behavioral therapy is the psychotherapy with the most evidence of efficacy for anxiety disorders compared with psychological or pill placebo (eg, generalized anxiety disorder: Hedges g = 1.01 [large effect size] [95% CI, 0.44 to 1.57]; social anxiety disorder: Hedges g = 0.41 [small to medium effect] [95% CI, 0.25 to 0.57]; panic disorder: Hedges g = 0.39 [small to medium effect[ [95% CI, 0.12 to 0.65]), including in primary care. When selecting treatment, clinicians should consider patient preference, current and prior treatments, medical and psychiatric comorbid illnesses, age, sex, and reproductive planning, as well as cost and access to care.Conclusions and RelevanceAnxiety disorders affect approximately 34% of adults during their lifetime in the US and are associated with significant distress and impairment. First-line treatments for anxiety disorders include cognitive behavioral therapy, SSRIs such as sertraline, and SNRIs such as venlafaxine extended release.
Purpose of the review The purpose of this review is to critically assess the evidence for exercise as an adjunct intervention for major depressive disorder and bipolar disorder, chronic conditions characterized by frequent comorbid conditions as well as interepisodic symptoms with poor quality of life and impaired functioning. Individuals with these mood disorders are at higher risk of cardiovascular disease and premature death in part because of increased rates of obesity, inactivity, and diabetes mellitus compared to the general population. Exercise may not only mitigate the increased risk of cardiovascular disease, but could also potentially improve the long term outcomes of mood disorders. Recent findings We conducted a literature review on the impact of exercise on mood disorders and associated comorbid conditions as well as possible biological mechanisms. We found that exercise impacts both the physical health parameters of mood disorders as well as mental health outcomes. Exercise also positively impacts conditions frequently comorbid with mood disorders (i.e. anxiety, pain, and insomnia). There are multiple candidate biomarkers for exercise, with brain-derived neurotrophic factor and oxidative stress as two main promising components of exercise’s anti-depressant effect. Summary Exercise appears to be a promising adjunct treatment for mood disorders. We conclude with recommendations for future research of exercise as an adjunct intervention for mood disorders.
Validation of the new DSM-5-TR criteria for prolonged grief disorder and the PG-13-Revised (PG-13-R) scale. World Psychiatry, 20(1),
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