Peripheral edema associated with antidepressant use: Systematic review of case reports

BACKGROUND

Oedema associated with psychotropics can impose a considerable burden, leading to increased morbidity and cost. Peripheral oedema is sometimes related to the use of antidepressants, which are among the most prescribed psychotropic medications. We reviewed the reported cases of antidepressant-associated oedema to understand the risk factors, aetiology and outcome.

METHODS

We searched the Medline, Web of Science and Embase databases to identify reported cases of peripheral oedema associated with antidepressant use. We included studies published in English and those with full-text availability. A systematic review of the reports was done to identify the antidepressants associated with oedema, explore possible risk factors, investigate potential mechanisms, and assess the outcome.

RESULTS

We identified a total of 45 cases (27 case reports and five case series) that reported oedema associated with antidepressant use. Almost all major classes of antidepressants were found to be associated with oedema. Among these drugs, trazodone, mirtazapine, and escitalopram were the most implicated. Older age and female gender were more commonly associated with oedema. Etiologically, antagonism of α1 adrenergic receptors and 5HT2A receptors, leading to vasodilation and oedema, emerged as the most prevalent mechanisms. In most cases, the oedema subsided following the discontinuation of the antidepressants.

CONCLUSIONS

Peripheral oedema associated with antidepressant use can represent a significant adverse drug reaction involving various classes of antidepressants. To ensure timely identification and proper management of oedema, regular monitoring is crucial.

Synthesis and anti-cancer potential of potent peripheral MAOA inhibitors designed to limit blood:brain penetration

Monoamine oxidases (MAOA/MAOB) are enzymes known for their role in neurotransmitter regulation in the central nervous system (CNS). Irreversible and non-selective MAO inhibitors (MAOi's) were the first class of antidepressants, thus subsequent work on drugs such as the selective MAOA inhibitor clorgyline has focussed on selectivity and increased CNS penetration. MAOA is highly expressed in high grade and metastatic prostate cancer with a proposed effect on prostate cancer growth, recurrence, and drug resistance. A Phase II Clinical Trial has demonstrated the therapeutic effects of the irreversible nonselective MAOi phenelzine for prostate cancer. However, neurologic adverse effects led to early withdrawal in 25% of the enrolled patient-population. In this work, we revised the clorgyline scaffold with the goal of decreasing CNS penetration to minimize CNS-related side effects while retaining or enhancing MAOA inhibition potency and selectivity. Using the known co-crystal structure of clorgyline bound with FAD co-factor in the hMAOA active site as a reference, we designed and synthesized a series of compounds predicted to have lower CNS penetration (logBB). All synthesized derivatives displayed favorable drug-like characteristics such as predicted Caco-2 permeability and human oral absorption, and exhibited highly selective hMAOA binding interactions. Introduction of an HBD group (NH2 or OH) at position 5 of the phenyl ring clorgyline resulted in 3x more potent hMAOA inhibition with equivalent or better hMAOB selectivity, and similar prostate cancer cell cytotoxicity. In contrast, introduction of larger substituents at this position or at the terminal amine significantly reduced the hMAOA inhibition potency, attributed in part to a steric clash within the binding pocket of the MAOA active site. Replacement of the N-methyl group by a more polar, but larger 2-hydroxyethyl group did not enhance potency. However, introduction of a polar 2-hydroxy in the propyl chain retained the highly selective MAOA inhibition and cancer cell cytotoxicity of clorgyline while reducing its CNS score from 2 to 0. We believe that these results identify a new class of peripherally directed MAOIs that may allow safer therapeutic targeting of MAOA for a variety of anti-cancer and anti-inflammatory indications.

On the Origins of MAOI Misconceptions: Reaffirming their Role in Melancholic Depression

The first monoamine oxidase inhibitors (MAOIs) used for the treatment of depression in the 1950-60s were credited with treating severe melancholic depression (MeD) successfully and greatly reducing the need for electroconvulsive therapy (ECT). Following the hiatus caused by the then ill-understood cheese reaction, MAOI use was relegated to atypical and treatment-resistant depressions only, based on data from insufficiently probing research studies suggesting their comparatively lesser effectiveness in MeD. The siren attraction of new 'better' drugs with different mechanisms amplified this trend. Following a re-evaluation of the data, we suggest that MAOIs are effective in MeD. Additionally, the broad unitary conceptualisation of major depressive disorder (MDD) in the DSM model diminished the chance of demonstrating distinctive responses to different antidepressant drugs (ADs) such as SSRIs, TCAs, and MAOIs, thereby further reducing the interest in MAOIs. More reliable categorical distinction of MeD, disentangling it from MDD, may be possible if more sensitive measuring instruments (CORE, SMPI) are used. We suggest these issues will benefit from re-appraisement via an inductive reasoning process within a binary (rather than a unitary) model for defining the different depressive disorders, allowing for the use of more reliable diagnostic criteria for MeD in particular. We conclude that MAOIs remain essential for, inter alia, TCA-resistant MeD, and should typically be used prior to ECT; additionally, they have a role in maintaining remission in cases treated with ECT (and ketamine/esketamine). We suggest that MAOIs should be utilized earlier in treatment algorithms and with greater regularity than is presently the case.

[70-year history of studying the effectiveness of therapy of patients with depression with antidepressants - irreversible nonselective monoamine oxidase inhibitors]

The history of studying the effectiveness of therapy of patients with depression by irreversible non-selective monoamine oxidase inhibitors (MAOIs) is analyzed and systematized. Authors describe the stages of the appearance of the first data on the effectiveness of treatment by the first representatives (the 50^s of the XX century), the targeted study of the effectiveness of the use of numerous «new» representatives and the emergence of disagreements in assessing the power of therapy (the end of the 50^s-60^s of the XX century), continuing to study the effectiveness of treatment by representatives who remained in clinical practice, and establishing its clinical predictors (80^s-90^s of the XX century), the appearance of the first data on the effectiveness of therapy for «atypical depression» (1959-1960) and further development of this issue (80^s-90^s of the XX century). The stage of formation and development of the idea of the effectiveness of treatment for resistant depression (late 70^s-90^s of the XX century) is characterized. Separately, the history of studying the effectiveness of application in the USSR and Russia (late 50^s- 90^s of the XX century) is outlined. The current state of the issue of assessing the effectiveness of therapy (the end of the 90^s of the XX century - 2022) is shown.

The prescriber's guide to classic MAO inhibitors (phenelzine, tranylcypromine, isocarboxazid) for treatment-resistant depression

This article is a clinical guide which discusses the "state-of-the-art" usage of the classic monoamine oxidase inhibitor (MAOI) antidepressants (phenelzine, tranylcypromine, and isocarboxazid) in modern psychiatric practice. The guide is for all clinicians, including those who may not be experienced MAOI prescribers. It discusses indications, drug-drug interactions, side-effect management, and the safety of various augmentation strategies. There is a clear and broad consensus (more than 70 international expert endorsers), based on 6 decades of experience, for the recommendations herein exposited. They are based on empirical evidence and expert opinion-this guide is presented as a new specialist-consensus standard. The guide provides practical clinical advice, and is the basis for the rational use of these drugs, particularly because it improves and updates knowledge, and corrects the various misconceptions that have hitherto been prominent in the literature, partly due to insufficient knowledge of pharmacology. The guide suggests that MAOIs should always be considered in cases of treatment-resistant depression (including those melancholic in nature), and prior to electroconvulsive therapy-while taking into account of patient preference. In selected cases, they may be considered earlier in the treatment algorithm than has previously been customary, and should not be regarded as drugs of last resort; they may prove decisively effective when many other treatments have failed. The guide clarifies key points on the concomitant use of incorrectly proscribed drugs such as methylphenidate and some tricyclic antidepressants. It also illustrates the straightforward "bridging" methods that may be used to transition simply and safely from other antidepressants to MAOIs.

The Prescriber's Guide to the MAOI Diet-Thinking Through Tyramine Troubles

This review article features comprehensive discussions on the dietary restrictions issued to patients taking a classic monoamine oxidase inhibitor (phenelzine, tranylcypromine, isocarboxazid), or high-dose (oral or transdermal) selegiline. It equips doctors with the knowledge to explain to their patients which dietary precautions are necessary, and why that is so: MAOIs alter the capacity to metabolize certain monoamines, like tyramine, which causes dose-related blood pressure elevations. Modern food production and hygiene standards have resulted in large reductions of tyramine concentrations in most foodstuffs and beverages, including many cheeses. Thus, the risk of consequential blood pressure increases is considerably reduced-but some caution remains warranted. The effects of other relevant biogenic amines (histamine, dopamine), and of the amino acids L-dopa and L-tryptophan are also discussed. The tables of tyramine data usually presented in MAOI diet guides are by nature unhelpful and imprecise, because tyramine levels vary widely within foods of the same category. For this reason, it is vital that doctors understand the general principles outlined in this guide; that way, they can tailor their instructions and advice to the individual, to his/her lifestyle and situation. This is important because the pressor response is characterized by significant interpatient variability. When all factors are weighed and balanced, the conclusion is that the MAOI diet is not all that difficult. Minimizing the intake of the small number of risky foods is all that is required. Many patients may hardly need to change their diet at all.

Revisiting monoamine oxidase inhibitors for the treatment of depressive disorders: A systematic review and network meta-analysis

BACKGROUND

Monoamine oxidase inhibitors (MAOIs) were the first class of modern antidepressants; however, they are under-utilized as compared to the newer antidepressants.

METHODS

In this systematic review, network meta-analysis was used to investigate the comparative efficacy and acceptability of MAOIs for depressive disorders. Overall, the network meta-analysis included 52 double-blind, randomized controlled trials (RCTs) that compared 14 antidepressants or placebo. Across studies, the mean arm size was n = 58 participants from a total N = 6462 (5309 active drug; 1153 placebo).

RESULTS

Except fluvoxamine, all antidepressants demonstrated superior efficacy to placebo, and none demonstrated substantially better or worse all-cause dropout rates. Phenelzine demonstrated superior evidence for efficacy compared to all other treatments, and clomipramine demonstrated superior evidence for acceptability compared to all other treatments.

LIMITATIONS

The study is primarily limited by low estimate precision due to a relative paucity of studies for some of the included treatment conditions. Further evidence is required to study the relative efficacy of MAOIs against newer antidepressants.

CONCLUSIONS

The results of this analysis largely support the re-evaluation of the use of MAOIs as antidepressant agents in the treatment algorithm of depression.

Anesthetic Considerations for Patients on Antidepressant Therapy-Part I

Millions of patients take antidepressant medications in the United States for the treatment of depression or anxiety disorders. Some antidepressants are prescribed off-label to treat problems such as chronic pain, low energy, and menstrual symptoms. Antidepressants are a broad and expansive group of medications, but the more common drug classes include tricyclic antidepressants, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and monoamine oxidase inhibitors. A miscellaneous or "atypical" category covers other agents. Some herbal supplements that claim to have antidepressant activity will also be discussed. In Part I of this review, antidepressant pharmacology, adverse effects, and drug interactions with adrenergic agonists will be discussed. In part II, drug interactions with sedation and general anesthetics will be reviewed. Bleeding effects and serotonin syndrome implications in anesthetic practice will also be highlighted.

Antinociceptive Effects of the Antidepressant Phenelzine are Mediated by Context-Dependent Inhibition of Neuronal Responses in the Dorsal Horn

The putative strong anti-nociceptive properties of the antidepressant phenelzine (PLZ) have not been widely explored as a treatment for pain. Antinociceptive effects of PLZ were identified in the formalin model of tonic pain (Mifflin et al., 2016) and in allodynia associated with experimental autoimmune encephalomyelitis, (EAE) a mouse model of multiple sclerosis (Potter et al., 2016). Here, we further clarify the specific types of stimuli and contexts in which PLZ modulates nociceptive sensitivity. Our findings indicate that PLZ selectively inhibits ongoing inflammatory pain while sparing transient reflexive and acute nociception. We also investigated the cellular mechanisms of action of PLZ in the dorsal horn, and as expected of a monoamine-oxidase inhibitor, PLZ increased serotonin (5HT) immunoreactivity. We next used two approaches to test the hypothesis that PLZ inhibits the activation of spinal nociresponsive neurons. First, we evaluated the formalin-evoked protein expression of the immediate early gene, c-fos. PLZ reduced Fos expression in the superficial dorsal horn. Second, we evaluated the effects of PLZ on intracellular calcium responses to superfusion of glutamate (0.3-1.0 mM) in an ex vivo lumbar spinal cord slice preparation. Superfusion with PLZ (100-300 μM) reduced 1 mM glutamate-evoked calcium responses. This was blocked by pretreatment with the 5HT1A-receptor antagonist WAY-100,635, but not the alpha-2 adrenergic antagonist idazoxan. We conclude that PLZ exerts antinociceptive effects through a 5-HT/5HT1AR-dependent inhibition of neuronal responses within nociceptive circuits of the dorsal horn.

Chronic CB1 cannabinoid receptor antagonism persistently increases dendritic spine densities in brain regions important to zebra finch vocal learning and production in an antidepressant-sensitive manner

During typical late-postnatal CNS development, net reductions in dendritic spine densities are associated with activity-dependent learning. Prior results showed agonist exposure in young animals increased spine densities in a subset of song regions while adult exposures did not, suggesting endocannabinoid signaling regulates dendritic spine dynamics important to vocal development. Here we addressed this question using the CB1 receptor-selective antagonist SR141716A (SR) to disrupt endocannabinoid signaling both during and after vocal learning. We hypothesized antagonist exposure during vocal development, but not adulthood, would alter spine densities. Following 25days of exposure and a 25day maturation period, 3D reconstructions of Golgi-Cox stained neurons were used to measure spine densities. We found antagonist treatments during both age periods increased densities within Area X (basal ganglia) and following adult treatments within HVC (premotor cortical-like). Results suggest both inappropriate cannabinoid receptor stimulation and inhibition are capable of similar disregulatory effects during establishment of circuits important to vocal learning, with antagonism extending these effects through adulthood. Given clinical evidence of depressant effects of SR, we tested the ability of the antidepressant monoamine oxidase inhibitor (MAOI) phenelzine to mitigate SR-induced spine density increases. This was confirmed implicating interaction between monoamine and endocannabinoid systems. Finally, we evaluated acute effects of these drugs to alter ability of novel song exposure to increase spine densities in auditory NCM and other regions, finding when combined, SR and phenelzine increased densities within Area X. These results contribute to understanding relevance of dendritic spine dynamics in neuronal development, drug abuse, and depression.

Modification of 5-methoxy-N,N-dimethyltryptamine-induced hyperactivity by monoamine oxidase A inhibitor harmaline in mice and the underlying serotonergic mechanisms

BACKGROUND

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are indolealkylamine (IAA) drugs often abused together. Our recent studies have revealed the significant effects of co-administered harmaline, a monoamine oxidase inhibitor (MAOI), on 5-MeO-DMT pharmacokinetics and thermoregulation. This study was to delineate the impact of harmaline and 5-MeO-DMT on home-cage activity in mouse models, as well as the contribution of serotonin (5-HT) receptors.

METHODS

Home-cage activities of individual animals were monitored automatically in the home cages following implantation of telemetry transmitters and administration of various doses of IAA drugs and 5-HT receptor antagonists. Area under the effect curve (AUEC) of mouse activity values were calculated by trapezoidal rule.

RESULTS

High dose of harmaline (15mg/kg, ip) alone caused an early-phase (0-45min) hypoactivity in mice that was fully attenuated by 5-HT1A receptor antagonist WAY-100635, whereas a late-phase (45-180min) hyperactivity that was reduced by 5-HT2A receptor antagonist MDL-100907. 5-MeO-DMT (10 and 20mg/kg, ip) alone induced biphasic effects, an early-phase (0-45min) hypoactivity that was completely attenuated by WAY-100635, and a late-phase (45-180min) hyperactivity that was fully suppressed by MDL-100907. Interestingly, co-administration of MAOI harmaline (2-15mg/kg) with a subthreshold dose of 5-MeO-DMT (2mg/kg) induced excessive hyperactivities at late phase (45-180min) that could be abolished by either WAY-100635 or MDL-100907.

CONCLUSIONS

Co-administration of MAOI with 5-MeO-DMT provokes excessive late-phase hyperactivity, which involves the activation of both 5-HT1A and 5-HT2A receptors.

Combination therapy with monoamine oxidase inhibitors and other antidepressants or stimulants: strategies for the management of treatment-resistant depression

Treatment-resistant depression (TRD) is a major health concern. More than 40% of patients treated for major depressive disorder with an appropriate antidepressant dose for an adequate duration fail to respond. Further, approximately half of adults with major depressive disorder fail to achieve sustained remission despite various medication trials. The utilization of monoamine oxidase inhibitors (MAOIs) for the treatment of depression in clinical practice today is low due to their widely known adverse effects, some of which may be life threatening, and the risk for dietary and drug interactions. For these reasons, MAOIs are not recommended to be prescribed along with other antidepressants or certain prescription or nonprescription drugs. Pharmacologic options are limited for individuals with TRD, however, and there is a paucity of data on the efficacy of MAOIs in combination with other antidepressants for the management of TRD. We performed a search of the PubMed database (inception through January 25, 2015) to identify cases that illustrate the potential utility, as well as risks, of combination treatment with MAOIs and other antidepressants for the management of TRD; 18 articles met the criteria for our search. In addition, we performed a retrospective case series by reviewing the medical records of 29 adults treated for depression with an MAOI plus another psychotropic agent (an antidepressant or stimulant medication) between 2003 and 2012 at a large Midwestern teaching hospital. We compared the findings of the published experience with our local experience to allow for more informed decisions regarding pharmacotherapy in patients with TRD. We separated the local experience into two groups: 15 cases with the selective MAO type B inhibitor selegiline combined with medications presumed to increase the risk of serotonin syndrome and 14 cases with nonselective MAOIs (phenelzine and tranylcypromine) combined with other contraindicated medications. Although risks of combination treatment certainly exist with selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, or clomipramine, the current literature supports cautious use of combining MAOIs with other antidepressants in patients with TRD who have failed multiple treatment modalities. In addition, the data from the 29 patients receiving combination therapy with an MAOI and another antidepressant or stimulant medication revealed that 21% improved significantly, with no complications. This case series and literature review suggest that when used under close supervision and under the care of an experienced clinician in psychiatry, combination therapy may be a consideration for the management of TRD in patients not responding to monotherapy or other combinations of antidepressants.

EMSAM (deprenyl patch): how a promising antidepressant was underutilized

The EMSAM patch is a unique monoamine oxidase inhibitor (MAOI) being the only antidepressant utilizing a transdermal delivery system. This was welcomed by clinicians who hoped that EMSAM would be better tolerated than oral MAOIs and non-MAOI antidepressants, as well as being effective for treatment in a wide spectrum of depressed patients including atypical depression, bipolar depression, and refractory depression. Unfortunately, the clinical use of EMSAM has been underutilized and its potential usefulness overlooked. This article suggests that fear of possible side effects, particularly the "cheese reaction" and serotonin syndrome, are some of the main contributors to underutilization by clinicians. These risks have been significantly exaggerated with the 6 mg/day dose not even requiring a special diet. Other contributing factors leading to underutilization are reviewed such as: the lack of studies addressing many important clinical questions; inadequate data analyses; not evaluating the effect of EMSAM on comorbid psychiatric conditions, particularly anxiety disorders; lack of antidepressant comparators versus EMSAM; no dose-response relationship examined; various depressive subtypes and conditions are unexplored, eg, bipolar depression and refractory depression; poor insurance coverage for an expensive medication; as well as minimal marketing efforts and postmarketing studies. On the other hand, many potential advantages of EMSAM are not highlighted enough in the literature and by pharmaceutical companies which might have increased clinical interest and utilization of the antidepressant. For example, the advantages of EMSAM include: avoidance of swallowing issues, as can be seen with oral antidepressants; minimal side effects, probably due to a favorable pharmacokinetic profile; minimal evidence of suicidal behavior, probably relating to the transdermal route of administration; low rates of inducing hypomanic/manic episodes; as well as significant efficacy in "anxious depression" and atypical depression. Recent efforts in conducting some post hoc analyses and presentations on EMSAM may yet stimulate further clinical interest and use of this antidepressant.

The occurrence of N-nitrosamines, residual nitrite and biogenic amines in commercial dry fermented sausages and evaluation of their occasional relation

Regarding food borne intoxications, the accumulation of biogenic amines must be avoided in all kinds of food products. Moreover, biogenic amines can function as precursors for the formation of carcinogenic N-nitrosamines when nitrite is present. To estimate the food safety of the dry fermented sausages available on the Belgian market, a screening of the residual sodium nitrite and nitrate contents, biogenic amines and volatile N-nitrosamine concentrations was performed on 101 samples. The median concentrations of residual NaNO2 and NaNO3 were each individually lower than 20mg/kg. In general, the biogenic amine accumulation remained low at the end of shelf life. Only in one product the amounts of cadaverine and putrescine reached intoxicating levels. Concerning the occurrence of N-nitrosamines, only N-nitrosopiperidine and N-nitrosomorpholine were detected in a high number of samples (resp. 22% and 28%). No correlation between the presence of N-nitrosamines and the biogenic amines content was observed. Although the N-nitrosamines could not been linked to specific product categories, the occurrence of N-nitrosopiperidine could probably be attributed to the use of pepper.

Remodeling of axo-spinous synapses in the pathophysiology and treatment of depression

Dendritic spines provide a compartment for assembly and functional organization of synaptic machinery that plays a fundamental role in neuronal communication and neuroplasticity. Studies in humans as well as in animal models have demonstrated abnormal spine architecture in several psychiatric disorders, including depression and other stress-related illnesses. The negative impact of stress on the density and organization of spines is thought to contribute to the behavioral deficits caused by stress exposure. Moreover, there is now evidence that medication-induced recovery involves changes in synaptic plasticity and dendrite morphology, including increased expression of pre- and postsynaptic plasticity-related proteins, as well as the density and function of axo-spinous synapses. Here we review the evidence from brain imaging and postmortem studies demonstrating that depression is accompanied by structural and functional alterations of cortical and limbic brain regions, including the prefrontal cortex, hippocampus and amygdala. In addition, we present more direct evidence from basic research studies that exposure to stress alters spine morphology, function and plasticity and that antidepressants, particularly new rapid acting agents, reverse these effects. Elucidation of the signaling pathways and molecular mechanisms that control spine synapse assembly and plasticity will contribute to a better understanding of the pathophysiology of depression and development of novel, more effective therapeutic agents.

The clinical pharmacology of depressive states

Antidepressants have good efficacy in the treatment of mood disorders, with effect sizes that have consistently been found to be greater than those of placebo. The more recent antidepressants do not have better efficacy than the compounds discovered 40 to 50 years ago, but they do have a more favorable configuration of side effects, leading to fewer dropouts. This favorable situation has made it possible to prescribe the newer antidepressants in less severe depression and in several anxiety disorders, with considerable benefit to patients. During the last decades, research into the pathophysiology of mood and anxiety disorders has provided much information on the brain circuitry, neurohormones, and neurotransmitters involved in these disorders. In parallel, biological and behavioral work on antidepressants, using animal models and new biochemical techniques, has led to a broader understanding of the mode of action of these drugs. Despite this impressive list of discoveries, much research remains to be done on the clinical, psychological, neuropsychological, physiological, and neurochemical aspects, before we can obtain a coherent description of the pathophysiological mechanisms of depression and its treatment. This will lead to a better ability to predict the quality of drug response and, therefore, to the individualization of treatment.

Emsam: the first year

We investigated the use of EMSAM in the first year post-launch in the US-April of 2006 through March of 2007. According to our data, EMSAM represents <0.1 percent of total prescriptions for antidepressants in the US and is prescribed most often by psychiatrists (83%of prescriptions). The impact of the product on the MAO inhibitor class, however, has been significant. We found that EMSAM now represents 30 percent of all MAO inhibitor use and has been a catalyst for growth in the overall MAO inhibitor class. An expert commentary is provided on the data.

The clinical pharmacology of depressive states

Antidepressants have good efficacy in the treatment of mood disorders, with effect sizes that have consistently been found to be greater than those of placebo. The more recent antidepressants do not have better efficacy than the compounds discovered 40 to 50 years ago, but they do have a more favorable configuration of side effects, leading to fewer dropouts. This favorable situation has made it possible to prescribe the newer antidepressants in less severe depression and in several anxiety disorders, with considerable benefit to patients. During the last decades, research into the pathophysiology of mood and anxiety disorders has provided much information on the brain circuitry, neurohormones, and neurotransmitters involved in these disorders. In parallel, biological and behavioral work on antidepressants, using animal models and new biochemical techniques, has led to a broader understanding of the mode of action of these drugs. Despite this impressive list of discoveries, much research remains to be done on the clinical, psychological, neuropsychological, physiological, and neurochemical aspects, before we can obtain a coherent description of the pathophysiological mechanisms of depression and its treatment. This will lead to a better ability to predict the quality of drug response and, therefore, to the individualization of treatment.

Abuse of monoamine oxidase inhibitors

Abuse of monoamine oxidase inhibitors is not common but there are a few cases of addiction in the literature. Most of these patients had an additional diagnosis, either history of past drug abuse or personality disorder and MAOI withdrawal symptoms have been reported. We encountered three patients who received MAOI under psychiatric care. They were all self medicated by increasing the doses on their own, experienced euphoria and visited various physicians to obtain MAOI prescriptions and manifested toxic states. One of our patients had a normal, another a schizoid and the third, an addictive personality. Two were addicted in the past to amphetamine. Therefore, it is important not to prescribe MAOI's to patients who have a history of amphetamine and other addictions.