Getting the balance right: Established and emerging therapies for major depressive disorders

An adrenal mass and increased catecholamines: monoamine oxidase or pheochromocytoma effect?

Hormonal evaluation in patients with an adrenal incidentaloma can be difficult in patients with comorbidities or in patients using interfering drugs. We present a case of a 54-year-old man who was evaluated for an adrenal mass. The medical history reported treatment with a monoamine oxidase (MAO) inhibitor for recurrent psychoses. Hormonal screening showed elevated levels of normetanephrine and metanephrine in plasma and urine, suggesting a diagnosis of pheochromocytoma (PHEO), and an adrenalectomy was performed. Histologic examination showed that the tumor had an origin of the adrenal cortex. MAO inhibitors are also known to cause elevated levels of catecholamines. In this case, a PHEO seemed more likely the cause due to repeatedly elevated levels of metanephrines and normal levels of catecholamines. Since the tumor had an origin of the adrenal cortex, the use of MAO inhibitors was the most likely explanation for the elevated levels of metanephrines. This case illustrated the difficulties in diagnosing PHEO, especially in patients with comorbidities and interfering drugs.

The gastrointestinal tract microbiome, probiotics, and mood

Mental health is closely linked to physical health. Depression (e.g., major depression) is highly prevalent worldwide and a major cause of disability. In a subgroup with treatment-resistant depression, standard pharmacotherapy interventions provide small if any incremental improvement in patient outcomes and may also require the application of an alternate approach. Therefore, in addition to the standard pharmacotherapies prescribed, patients will also be advised on the benefits of psychological counseling, electroconvulsive therapy, and transcranial magnetic stimulation or increasing physical activity and reducing harmful substance consumption. Numerous nutraceuticals have a beneficial role in treatment-resistant depression and include, herbal medicines of which Hypericum perforatum is the best studied, omega-3 fatty acid preparations, S-Adenosyl-L-Methionine (SAMe), various mineral formulations (e.g., magnesium) and folate (singly or in combination with B group vitamins) are prescribed to a lesser extent. Furthermore, a largely neglected area of research activity has been the role of live probiotic cultures that contribute to repairing dysbiosis (a leaky gut barrier abnormality) in the gastrointestinal tract (GIT). In this commentary, we build a hypothesis that in addition suggests that GIT metabolites that are elaborated by the microbiome cohort may provide novel and significant avenues for efficacious therapeutic interventions for mood disorders. We posit that the microbiome in the gastrointestinal tract is implicit as an important participant for the amelioration of adverse mood conditions via the diverse metabolic activities provided by live beneficial bacteria (probiotics) as an active adjuvant treatment. This activity is in part triggered by a controlled release of reactive oxygen species (ROS) and hence further questions the antioxidant/oxidative stress postulate.

The importance of norepinephrine in depression

Depression is one of the most common psychological diseases with significant potential morbidity and mortality. Although the underlying pathophysiology of depression has not been clearly defined, preclinical and clinical evidence suggest disturbances in serotonin (5-HT), norepinephrine (NE), and dopamine (DA) neurotransmission in the central nervous system. Virtually all currently available antidepressants act on one or more of the following mechanisms: inhibition of reuptake of 5-HT or NE (and DA), antagonism of inhibitory presynaptic 5-HT or NE receptors, or inhibition of monoamine oxidase. All of these mechanisms result in an enhanced neurotransmission of 5-HT and/or NE. Evidence for the involvement of NE in depression is abundant, and recent studies on neuronal pathways and symptoms highlight the specific role of NE in this disorder. NE plays a determinant role in executive functioning regulating cognition, motivation, and intellect, which are fundamental in social relationships. Social dysfunction is possibly one of the most important factors affecting the quality of life in depressed patients.