Neurobiological similarities in antidepressant sleep deprivation and psychostimulant use: a psychostimulant theory of antidepressant sleep deprivation.

This paper attempts to summarize the evidence for the hypothesis that psychostimulant-like neurotransmitter processes within certain regions of the limbic system induce the positive effects of antidepressant sleep deprivation (SD). Preclinical and human studies indicate similar neurobiological effects of psychostimulants such as amphetamines, cocaine and SD. In clinical use, SD and psychostimulants have similar characteristics and behavioral effects. Furthermore, acute psychostimulant challenge decreases limbic metabolism in imaging studies, and SD decreases elevated limbic metabolism in SD responders, indicating that psychostimulant-like neurotransmitter release could decrease limbic metabolism in SD responders. Most antidepressant pharmacotherapies change the reactivity of the dopamine system, and a decrease of presynaptic dopamine or postsynaptic availability can induce depression. Sleep is accompanied by a reduction of catecholamine release and those processes which are increased by psychostimulants. It is concluded that a proposed regional postsynaptic deficit in catecholaminergic neurotransmission can be overcome either acutely by enhanced release during SD or psychostimulant use, or chronically by changes in receptor sensitivity or gene expression due to antidepressant therapies. A postsynaptic deficit in these areas becomes evident if presynaptic release is reduced in conditions such as sleep. Therefore, sleep is depressiogenic for predisposed individuals and the reduction of sleep avoids understimulation of subsensitive postsynaptic processes, which are enhanced by psychostimulants.