Peter D. Drummond

A review of lifestyle factors that contribute to important pathways associated with major depression: Diet, sleep and exercise

Research on major depression has confirmed that it is caused by an array of biopsychosocial and lifestyle factors. Diet, exercise and sleep are three such influences that play a significant mediating role in the development, progression and treatment of this condition. This review summarises animal- and human-based studies on the relationship between these three lifestyle factors and major depressive disorder, and their influence on dysregulated pathways associated with depression: namely neurotransmitter processes, immuno-inflammatory pathways, hypothalamic-pituitary-adrenal (HPA) axis disturbances, oxidative stress and antioxidant defence systems, neuroprogression, and mitochondrial disturbances. Increased attention in future clinical studies on the influence of diet, sleep and exercise on major depressive disorder and investigations of their effect on physiological processes will help to expand our understanding and treatment of major depressive disorder. Mental health interventions, taking into account the bidirectional relationship between these lifestyle factors and major depression are also likely to enhance the efficacy of interventions associated with this disorder.

A review of peripheral biomarkers in major depression: the potential of inflammatory and oxidative stress biomarkers.

Biomarkers are regularly used in medicine to provide objective indicators of normal biological processes, pathogenic processes or pharmacological responses to therapeutic interventions, and have proved invaluable in expanding our understanding and treatment of medical diseases. In the field of psychiatry, assessment and treatment has, however, primarily relied on patient interviews and questionnaires for diagnostic and treatment purposes. Biomarkers in psychiatry present a promising addition to advance the diagnosis, treatment and prevention of psychiatric diseases. This review provides a summary on the potential of peripheral biomarkers in major depression with a specific emphasis on those related to inflammatory/immune and oxidative stress/antioxidant defences. The complexities associated with biomarker assessment are reviewed specifically around their collection, analysis and interpretation. Focus is placed on the potential of peripheral biomarkers to aid diagnosis, predict treatment response, enhance treatment-matching, and prevent the onset or relapse of major depression.

Scalp Tenderness and Sensitivity to Pain in Migraine and Tension Headache

SYNOPSIS

Harlequin syndrome: the sudden onset of unilateral flushing and sweating.

Facial flushing and sweating were investigated in five patients who complained of the sudden onset of unilateral facial flushing in hot weather or when exercising vigorously. One patient probably suffered a brainstem infarct at the time that the unilateral flush was first noticed, and was left with a subtle Horners syndrome on the side opposite to the flush. The other four had no other neurological symptoms and no ocular signs of Horners syndrome. Thermal and emotional flushing and sweating were found to be impaired on the non-flushing side of the forehead in all five patients whereas gustatory sweating and flushing were increased on that side in four of the five patients, a combination of signs indicating a deficit of the second sympathetic neuron at the level of the third thoracic segment. CT and MRI of this area failed to disclose a structural lesion but latency from stimulation of the motor cortex and thoracic spinal cord to the third intercostal muscle was delayed on the non-flushing side in one patient. The complaint of unilateral flushing and sweating was abolished in one patient by ipsilateral stellate ganglionectomy. The unilateral facial flushing and sweating induced by heat in all five patients was thus a normal or excessive response by an intact sympathetic pathway, the other side failing to respond because of a sympathetic deficit. The onset in the four cases of peripheral origin followed strenuous exertion, which suggested that an anterior radicular artery may have become occluded at the third thoracic segment during torsion of the thoracic spine.

Pain increases during sympathetic arousal in patients with complex regional pain syndrome

Objective: To investigate the effect of sympathetic arousal on pain and vasomotor responses in healthy control subjects and patients with complex regional pain syndrome (CRPS), and to determine whether pain increases in patients with particular symptoms. Methods: In experiments 1 and 2, capsaicin was applied to the forearm of 24 healthy subjects to induce thermal hyperalgesia. Vascular responses were monitored and subjects rated thermal hyperalgesia before and after being startled (experiment 1), and before, during, and after mental arithmetic, breath holding, forehead cooling, the Valsalva maneuver, and a cold pressor test in experiment 2. In a third experiment, sensitivity to heat, cold, and mechanical stimulation was investigated in 61 patients with CRPS. Pain ratings and vascular and electrodermal responses were recorded after patients were startled and during forehead cooling. Results: In experiment 1, thermal hyperalgesia decreased in healthy control subjects after they were startled, and digital blood vessels constricted symmetrically. In experiment 2, thermal hyperalgesia decreased during and after other forms of sympathetic arousal. However, in experiment 3, ratings of clinical pain increased during forehead cooling or after being startled in over 70% of patients with CRPS. Pain increased most consistently during forehead cooling in patients with cold allodynia or punctate allodynia. Digital blood vessels constricted more intensely on the symptomatic than the nonsymptomatic side in patients with CRPS during sympathetic arousal. Conclusions: Normal inhibitory influences on pain during sympathetic arousal are compromised in the majority of patients with CRPS. The augmented vasoconstrictor response in the symptomatic limb during sympathetic arousal is consistent with adrenergic supersensitivity. An adrenergic sensitivity in nociceptive afferents might contribute to pain and hyperalgesia during sympathetic arousal in certain patients with CRPS.

Reduction of allodynia in patients with complex regional pain syndrome: A double-blind placebo-controlled trial of topical ketamine.

ABSTRACT A double‐blind placebo‐controlled crossover trial was used to determine the effects of topical ketamine, an N‐methyl‐d‐aspartate (NMDA) receptor antagonist, on the sensory disturbances in 20 patients with complex regional pain syndrome (CRPS). On two occasions separated by at least one week, sensory tests to light touch, pressure, punctate stimulation, light brushing and thermal stimuli were performed in the symptomatic and contralateral limb and on each side of the forehead before and 30 min after 10% ketamine cream was applied to the symptomatic or healthy limb. Venous blood for the plasma estimations of ketamine and norketamine was obtained 1 h after application of the creams. Ketamine applied to the symptomatic limb inhibited allodynia to light brushing and hyperalgesia to punctate stimulation. Systemic effects of the ketamine are unlikely to account for this as the plasma levels were below detectable limits. As touch thresholds were unchanged, NMDA receptors may contribute to the sensory disturbances in CRPS via actions at cutaneous nociceptors. Allodynia and hyperalgesia were detected in the ipsilateral forehead to a range of stimuli (brushing, pressure, punctate stimulation, cold, heat, and warmth). In several patients, ketamine treatment of the symptomatic limb inhibited allodynia to brushing the ipsilateral forehead, suggesting that the mechanism that mediates allodynia in the symptomatic limb contributed to allodynia at more remote sites. The present study shows promise for the use of topical ketamine as opposed to parenteral and oral forms which often result in undesirable side effects.

A cognitive behavioural approach to preventing anxiety during magnetic resonance imaging

This study evaluated a relaxation intervention designed to prevent anxiety during magnetic resonance imaging (MRI), and assessed the development of fears in patients who felt anxious during the procedure. Patients were assigned to a control condition (no intervention; n = 52), relaxation before the scan (n = 44), or relaxation before and during the scan (n = 43). Compared to the control group, patients who practised relaxation showed reduced anxiety during the scan. Seven months or more after undergoing MRI, there was a positive correlation between anxiety experienced during the scan and the development of MRI-related fears. The intervention did not prevent the development of MRI-related fears at follow-up.

A Quantitative Assessment of Photophobia in Migraine and Tension Headache

SYNOPSIS

Obesity and psychiatric disorders: Commonalities in dysregulated biological pathways and their implications for treatment

Rates of obesity are higher than normal across a range of psychiatric disorders, including major depressive disorder, bipolar disorder, schizophrenia and anxiety disorders. While the problem of obesity is generally acknowledged in mental health research and treatment, an understanding of their bi-directional relationship is still developing. In this review the association between obesity and psychiatric disorders is summarised, with a specific emphasis on similarities in their disturbed biological pathways; namely neurotransmitter imbalances, hypothalamus-pituitary-adrenal axis disturbances, dysregulated inflammatory pathways, increased oxidative and nitrosative stress, mitochondrial disturbances, and neuroprogression. The applicability and effectiveness of weight-loss interventions in psychiatric populations are reviewed along with their potential efficacy in ameliorating disturbed biological pathways, particularly those mediating inflammation and oxidative stress. It is proposed that weight loss may not only be an effective intervention to enhance physical health but may also improve mental health outcomes and slow the rate of neuroprogressive disturbances in psychiatric disorders. Areas of future research to help expand our understanding of the relationship between obesity and psychiatric disorders are also outlined.

Noradrenaline increases hyperalgesia to heat in skin sensitized by capsaicin

&NA; Neurophysiological and behavioural observations in animals suggest that sympathetic neural activity and noradrenaline have an excitatory effect on nociceptor discharge in inflamed skin. To determine whether noradrenaline influences pain sensations in humans, heat hyperalgesia in forearm skin sensitized by topical application of 0.6% capsaicin was measured at sites of noradrenaline or saline ionophoresis in 10 healthy subjects. At control sites and sites of saline ionophoresis heat hyperalgesia decreased over the course of the experiment as inflammation subsided. In contrast, heat hyperalgesia persisted at sites of noradrenaline ionophoresis. These findings are consistent with neurophysiological observations that noradrenaline and sympathetic neural stimulation increase nociceptor discharge in inflamed skin, and suggest that sympathetic neural activity might increase pain associated with skin damage.