Monoamine depletion in non-pharmacological treatments for depression

Pathophysiology of depression and mechanisms of treatment

Major depression is a serious disorder of enormous sociological and clinical relevance. The discovery of antidepressant drugs in the 1950s led to the first biochemical hypothesis of depression, which suggested that an impairment in central monoaminergic function was the major lesion underlying the disorder. Basic research in all fields of neuroscience (including genetics) and the discovery of new antidepressant drugs have revolutionized our understanding of the mechanisms underlying depression and drug action. There is no doubt that the monoaminergic system is one of the cornerstones of these mechanisms, but multiple interactions with other brain systems and the regulation of central nervous system function must also be taken into account In spite of all the progress achieved so far, we must be aware that many open questions remain to be resolved in the future.

Blunted prolactin response to fentanyl in depression. Normalizing effect of partial sleep deprivation

There is some evidence that sleep deprivation (SD) might exert its antidepressant properties by involving endogenous opioid mechanisms. The authors investigated the effects of mu-receptor agonist administration on prolactin release in depressed patients before and after partial SD. Medication-free female depressed inpatients (N=18) were participating in two fentanyl challenge tests after partial SD and undisturbed sleep, 3 days apart in random order. Healthy volunteer women (N=10) were enrolled after full night sleep as comparison subjects. Five of them had placebo trials. Participants were given an intravenous injection of 0.1 mg/70 kg fentanyl at 9:00 AM. The prolactin secretory response to the opiate agonist was investigated for 1 h with serial blood sampling. After a night of undisturbed sleep, fentanyl administration prompted increases in plasma prolactin concentrations with blunted responses found in the depressed group. Following partial SD, the stimulated prolactin secretion of depressed patients increased significantly and was comparable to the response of comparison subjects. These findings suggest that SD acts via an opioid/dopamine-related mechanism. An alternative explanation, based on serotonin involvement is addressed in the discussion.

Potential mechanisms of the sleep therapies for depression

Sleep deprivation for one night has been investigated as a treatment for depression since the first publications describing its antidepressant properties almost 30 years ago [Pflug and Tolle, 1971: Int Pharmacopsychiatry 6:187-196]. It remains a field of active research. It is the only intervention consistently demonstrated to produce next-day antidepressant results. This makes sleep deprivation an exciting and unique tool to study the pathophysiology of depressive disorders and to formulate targets for novel antidepressant agents. Importantly, it is also an effective, but underused, clinical treatment for unipolar and bipolar depression.

The clinical response to total sleep deprivation and recovery sleep in geriatric depression: potential indicators of antidepressant treatment outcome

The clinical response to antidepressant treatment in late-life depression is often delayed and highly variable. Better indicators of antidepressant efficacy are needed early in the course of treatment, so that augmentation strategies or alternative treatments may be initiated. The goal of this study was to evaluate whether the change in the Hamilton depression rating scale (HDRS) after 36 h of total sleep deprivation (TSD) and recovery sleep predicted clinical outcome after 12 weeks of antidepressant treatment, and whether greater predictive value was observed in certain aspects of depressive symptomology. Fifteen elderly patients diagnosed with major depression underwent combined treatment with an initial 36 hours of TSD and a 12-week trial with the antidepressant paroxetine. Six HDRS subscores were evaluated with respect to how the changes after TSD and after one night of recovery sleep correlated with HDRS scores after 12 weeks of treatment. A significant correlation was obtained between the change in the core depressive symptomology subscale from baseline to recovery sleep and the HDRS score at 12 weeks, but the correlation was not significant when evaluating the change from baseline to TSD. These results indicate that the decrease in symptoms after recovery sleep compared with baseline levels (indicating the persistence of the antidepressant response), rather than the symptom reduction after TSD, has greater predictive value with respect to treatment outcome.