Serotonin receptor, SERT mRNA and correlations with symptoms in males with alcohol dependence and suicide.

OBJECTIVE: This study tested the hypothesis that abnormalities in components of the serotonin (5HT) system in the prefrontal cortex are associated with suicide in alcohol-dependent subjects. Second, we assessed the relationship of lifetime impulsivity and mood symptoms with prefrontal cortex 5-HT measures. METHOD: Tissue was obtained from Brodmann's areas (BA) 9 and 24 in postmortem samples of individuals who were alcohol dependent with suicide (n = 5), alcohol dependent without suicide (n = 9) and normal controls (n = 5). Serotonin receptor (5HT) and serotonin reuptake transporter (SERT) mRNA were measured. Interviews with next of kin estimated lifetime impulsivity and mood symptoms in the last week of life. RESULTS: Serotonin receptor 1A (5HT1A) mRNA in BA 9 was elevated in the alcohol dependence without suicide group compared with controls. In the alcohol dependence with suicide group, anxiety symptoms were associated with decreased BA 24 SERT mRNA and depressive symptoms with BA 9 5HT1A mRNA expression. In the alcohol dependent only group impulsivity is correlated with increased BA 9, and BA 24 serotonin receptor 2A mRNA. CONCLUSION: Our data suggest region-specific change, rather than global serotonin blunting is involved in alcohol dependence and suicide. It also suggests that symptoms are differentially influenced by prefrontal cortex serotonin receptor mRNA levels.

Association between a serotonin transporter promoter region polymorphism and mood response during tryptophan depletion.

This study investigated the relationship between depressive symptom response during tryptophan (TRP) depletion and a functional polymorphism of the promoter region of the serotonin (5-HT) transporter gene (SLC6A4).(1) Forty-three subjects in remission from a major depressive episode who underwent TRP depletion were genotyped. DNA was extracted from blood lymphocytes or from cheek cells.(2) The two common alleles are designated long (l) and short (s). Depressive symptoms were measured with the 25-item Hamilton Depression Rating Scale (HDRS).(3) There was a significant association between the l homozygous genotype and the depressive response to TRP depletion, with a significant main effect of time (F = 8.763, df = 3, 38, P = <0.001), and time x l homozygous allele interaction (F = 3.676, df = 3, 38, P = 0.02). Individuals whose genotype predicted increased 5-HT transporter activity may be more susceptible to depressive changes in response to transient 5-HT perturbations. The use of endophenotypic markers for affective disorders such as the mood response to TRP depletion may facilitate studies of complex genetic traits such as depression by decreasing its heterogeneity.

Living with anxiety disorders: as good as it gets...?

The high prevalence of anxiety disorders, along with the high rate of associated comorbidity, leads to significant financial burden and human suffering, making early detection and proper intervention a clinical priority for these conditions. Despite advances in the understanding and treatment of anxiety disorders, a number of factors diminish the likelihood that people with anxiety will benefit from these advances. The authors discuss current issues relating to the treatment of anxiety disorders. This review highlights the need for recognition of comorbid conditions, the importance of reducing the high rates of partial treatment response, the importance of being aware of the common utilization of alternative treatment interventions, and the need to recognize and treat medication-induced sexual dysfunction.

Tryptophan depletion and risk of depression relapse: a prospective study of tryptophan depletion as a potential predictor of depressive episodes.

BACKGROUND: This study investigated the relationship between depressive symptom response during tryptophan depletion and future depressive episodes. METHODS: Twelve subjects with prior major depressive episodes in remission and medication-free for > or =3 months (patients), and 12 matched healthy (control) subjects received two tryptophan depletion tests 1 week apart. During follow-up the Hamilton Depression Rating Scale was administered weekly for 1 month, monthly for 3 months, and once at 6 and 12 months. RESULTS: With results from both tests, tryptophan depletion has a sensitivity of 78%, specificity of 80%, positive predictive value of 70%, and negative predictive value of 86% to identify future depressive episodes. Survival analysis shows that mood response to tryptophan depletion reliably predicts major depressive episodes during the follow-up year (r =.2725, p =.014). CONCLUSIONS: Tryptophan depletion may be clinically useful in identifying individuals at risk for future major depressive episodes.

Depression: the case for a monoamine deficiency.

The monoamine hypothesis of depression predicts that the underlying pathophysiologic basis of depression is a depletion in the levels of serotonin, norepinephrine, and/or dopamine in the central nervous system. This hypothesized pathophysiology appears to be supported by the mechanism of action of antidepressants: agents that elevate the levels of these neurotransmitters in the brain have all been shown to be effective in the alleviation of depressive symptoms. However, intensive investigation has failed to find convincing evidence of a primary dysfunction of a specific monoamine system in patients with major depressive disorders. Understanding of the etiology of depression has been hampered by the absence of direct measurements of monoamines in humans. However, the monoamine depletion paradigm, which reproduces the clinical syndrome, allows a more direct method for investigating the role of monoamines. Results from such studies show that antidepressant responses are transiently reversed, with the response being dependent on the class of antidepressant. In contrast, monoamine depletion does not worsen symptoms in depressed patients not taking medication, nor does it cause depression in healthy volunteers with no depressive illness. In conclusion, it is clear that antidepressant agents in current use do indeed require intact monoamine systems for their therapeutic effect. However, some debate remains as to the precise role that a deficiency in monoamine system(s) may play in depression itself.

Role of norepinephrine in depression.

This article reviews the role of norepinephrine (NE) and serotonin (5-HT) in depression and the therapeutic effects of antidepressant drugs from the perspective of human neurotransmitter depletion studies. The data reviewed suggest that both noradrenergic and serotonergic systems are involved in antidepressant action, but the specific impairment that underlies depression is unclear and is likely to vary among patients. Results from neurotransmitter depletion studies in depressed patients who have responded to treatment suggest that, while interactions between NE and 5-HT are likely, neither of these 2 neurotransmitter systems is the final common pathway for the therapeutic effect of antidepressant drugs. NE-selective antidepressant drugs appear to be primarily dependent on the availability of NE for their effects. Likewise, 5-HT-selective antidepressants appear to be primarily dependent on the availability of 5-HT for their effects. Antidepressants that cause effects on both noradrenergic and serotonergic systems-such as mirtazapine-may be dependent on the availability of both neurotransmitters for their effects. Neither 5-HT nor NE depletion induced clinical depression in healthy subjects or worsened depression in unmedicated symptomatic patients with major depression. This finding suggests that the cause of depression is more complex than just an alteration in the levels of 5-HT and/or NE. For some patients, depression may be more directly caused by dysfunction in brain areas or neuronal systems modulated by monoamine systems. We propose that antidepressant drugs may enhance neurotransmission in normal noradrenergic or serotonergic neurons and, through a time-dependent but as yet undiscovered process, restore function to brain areas modulated by monoamine neurons. Future research should focus on understanding the adaptive changes that follow enhancement of synaptic levels of monoamines in neuronal circuits of the frontal cortex, amygdala, and hippocampus. Research investigating the neurobiology of depression may be more informed if the focus is shifted to investigating areas of the brain modulated by monoamine systems rather than the monoamine systems themselves.

Approaches to the enhancement of patient adherence to antidepressant medication treatment.

The number of safe and effective medication treatments for depression has increased significantly over the past 10 years. Relative to the older tricyclic antidepressants and monoamine oxidase inhibitors, the newer medications offer comparable efficacy with fewer side effects and a markedly reduced risk for serious adverse effects. In spite of these benefits, and in spite of the extensive and successful efforts that have been made to inform the general population about the diagnosis and treatment of depression, many patients do not comply with treatment recommendations. Although specific factors such as side effects lead to high rates of noncompliance with medication treatment, noncompliance is a multifactorial phenomenon. The reasons for noncompliance can include rational and intentional decisions based on beliefs about the illness, concerns over side effects, ineffectiveness of treatment. costs of the medication, decisions influenced by the symptoms of the disorder, and many other cultural and attitudinal factors. Some of the important concepts that should be addressed with depressed patients are reviewed. Strategies aimed at informing patients about depression and its treatment and providing a collaborative treatment environment have the potential to significantly improve treatment outcome and treatment adherence.

The Arizona Sexual Experience Scale (ASEX): reliability and validity.

Although sexual dysfunction is common in psychiatric patients, quantification of sexual dysfunction is limited by the paucity of validated, user-friendly scales. In order to address this problem, the authors have developed the Arizona Sexual Experiences Scale (ASEX), a five-item rating scale that quantifies sex drive, arousal, vaginal lubrication/penile erection, ability to reach orgasm, and satisfaction from orgasm. Possible total scores range from 5 to 30, with the higher scores indicating more sexual dysfunction. This study assesses the internal consistency, test-retest reliability, and convergent and discriminant validity of the ASEX.

Tryptophan depletion and depressive vulnerability.

BACKGROUND: Rapid and transient depletion of tryptophan (TRP) causes a brief depressive relapse in most patients successfully treated with and taking selective serotonin reuptake inhibitors, but little change in drug-free, symptomatic depressed patients. This study investigates the effects of TRP depletion in drug-free subjects in clinical remission from a prior major depressive episode (MDE). METHODS: Twelve subjects with a prior MDE, currently in clinical remission and drug-free for at least 3 months (patients), and 12 healthy subjects without personal or family history of Axis I disorder (controls), received TRP depletion. The study was conducted in a double-blind, controlled [full (102-g) and quarter-strength (25 g) 15-amino acid drinks], crossover fashion. Behavioral ratings and plasma TRP levels were obtained prior to, during, and after testing. RESULTS: All subjects experienced significant depletion of plasma TRP on both test-drinks, showing a significant dose-response relation. Healthy control subjects had minimal mood changes, but patients had a depressive response of greater magnitude. CONCLUSIONS: In the context of prior TRP depletion studies with antidepressant-treated, and drug-free symptomatic depressed patients, these results suggest that depression may be caused not by an abnormality of 5-HT function, but by dysfunction of other systems or brain regions modulated by 5-HT.

Tryptophan-depletion challenge in depressed patients treated with desipramine or fluoxetine: implications for the role of serotonin in the mechanism of antidepressant action.

BACKGROUND: Brain serotonin (5-HT) content is dependent on plasma levels of the essential amino acid, tryptophan (TRP). We have previously reported that rapid TRP depletion more frequently reversed the antidepressant response to monoamine oxidase inhibitors and 5-HT reuptake inhibitors than to desipramine (DMI). This study further investigates the relationship of relapse during TRP depletion to antidepressant type in nonrefractory, depressed patients randomly assigned to treatment with either DMI or fluoxetine (FLU). METHODS: Fifty-five drug-free depressed (DSM-III-R) patients were randomly assigned to antidepressant treatment with either DMI or FLU. All patients were either treatment naive (n = 34) or had previously received successful antidepressant treatment (n = 21). During the treatment phase, 35 patients had therapeutic responses by predetermined criteria (DMI 18/25; FLU 17/23) and 30 of these (15 DMI responders and 15 FLU responders) went on to TRP depletion testing. Patients received two 2-day test sessions involving administration of similar amino acid drinks. One session led to rapid TRP depletion and the other did not. Behavioral ratings [Hamilton Depression Scale (HDRS)] and plasma for TRP levels were obtained prior to, during, and after testing. Relapse was defined as a 50% increase in HDRS with total < or = 17. RESULTS: Total and free TRP decreased 70% to 80% 5 hours after the TRP-free drink. While 8/15 FLU responders relapsed, only 1/15 of the DMI responders relapsed. No patient experienced significant depressive symptoms during control testing. CONCLUSIONS: Rapid depletion of plasma TRP transiently reverses the antidepressant response in many patients on FLU but not DMI. Depressive relapse during TRP depletion appears to be more related to antidepressant type than to patient variables since patients were randomly assigned to the two treatments. Antidepressant response to FLU appears to be more dependent on 5-HT availability than that of DMI, suggesting that antidepressants mediate their therapeutic effects through different mechanisms.

Reboxetine: a review of efficacy and tolerability.

Clinical data on the efficacy and tolerability of the novel selective noradrenergic reuptake inhibitor reboxetine are reviewed. Reboxetine appears to have almost no pharmacological activity other than potently blocking the reuptake of noradrenaline. Clinical studies show reboxetine to be highly effective for the treatment of major depression. Reboxetine is more effective than placebo and comparable in efficacy to tricyclic antidepressants and selective serotonin reuptake inhibitors. Some studies suggest that reboxetine may have slightly better efficacy than fluoxetine and imipramine. Reboxetine is effective in severely depressed patients as well as elderly depressed persons. Reboxetine is remarkably well tolerated, having very few side effects. Reboxetine appears to cause little sexual dysfunction. The most common side effects are dry mouth and constipation. The drug does not inhibit or induce hepatic cytochrome P450 enzymes and is safe in overdose. Reboxetine may prove to be as effective and better tolerated than any other antidepressant currently available.

Different roles for serotonin in anti-obsessional drug action and the pathophysiology of obsessive-compulsive disorder.

BACKGROUND: There is a major role for serotonin in the mechanism of anti-obsessional drug action. Drugs that block uptake of noradrenaline are not effective in the treatment of obsessive-compulsive disorder (OCD), while drugs that potently bock serotonin reuptake are effective. While enhancement of serotonin neurotransmission is clearly involved in the treatment of OCD, the role of serotonin in the pathophysiology of OCD is less clear. METHOD: This paper provides a brief, focused review of the literature regarding treatment of OCD, the effects of drugs with selective action at various serotonin receptors and results of neurotransmitter depletion studies in patients with OCD. RESULTS: Some patients with OCD may experience remission of OCD symptoms during intoxication with psychedelic drugs that have potent 5-HT2A/2C agonist activity. These findings, coupled with results from serotonin depletion studies in depressed and OCD patients, suggest that enhancement of serotonin neurotransmission may underlie both antidepressant and anti-obsessional drug action, although the targeted brain areas may differ. CONCLUSIONS: OCD may not involve a dysfunction of the serotonin system. Rather, it is more likely to involve a dysfunction of specific brain circuits, particularly in the frontal cortex. Modulation of these circuits by serotonin neurons may underlie the specific action of anti-obsessional drugs.

Lithium and desipramine versus desipramine alone in the treatment of severe major depression: a preliminary study.

Improvement following lithium augmentation is well-documented in depressed patients resistant to tricyclic antidepressants. However, response latency to lithium augmentation is extremely variable, suggesting other mechanisms may be involved. To evaluate whether long-term tricyclic treatment is necessary for lithium augmentation's effect, the rapidity and magnitude of response to lithium combined with desipramine from the start of treatment was compared to desipramine alone in severely depressed patients. Patients with DSM-III-R major depression were randomized to double-blind, placebo-controlled treatment with either lithium + desipramine or placebo + desipramine for 4 weeks. Response criteria were based on Hamilton Depression Rating Scale scores and global improvement. Analysis of covariance of Hamilton scores demonstrated that lithium + desipramine was superior to placebo + desipramine at week 1 (P < 0.009), week 2 (P < 0.028), and week 3 (P < 0.07), although not at week 4. There were more responders to the combination than to monotherapy (P < 0.042). These preliminary data suggest that lithium + desipramine may have some efficacy in severely depressed patients. Further studies with larger samples are needed to confirm these findings.

Predictors of response to acute treatment of chronic and double depression with sertraline or imipramine.

BACKGROUND: The literature on predictors of response to treatment of nonchronic major depression has identified shorter duration of illness, acute onset, and less severity of illness as positive predictors. Unfortunately, there are almost no data on predictors of response to treatment for chronic depression. This study examined predictors of response to pharmacotherapy (sertraline or imipramine) in the treatment of outpatients who had DSM-III-R-defined chronic major or double depression. METHOD: The acute phase of the Chronic Major Depression and Double Depression Study is a double-blind, randomized, parallel-group 12-week comparison of sertraline and imipramine. Analyses are based on 623 patients who comprised the intent-to-treat sample, of whom 299 were nonresponders and 324 were responders, defined by a priori criteria as either remission or satisfactory therapeutic response. A stepwise logistic multiple regression analysis was performed on candidate clinical, psychosocial, and demographic variables previously identified as statistically significant in an attempt to develop a predictive model of positive antidepressant response. RESULTS: The sociodemographic variables that were predictive of positive response included living with spouse or partner or being at least a high school graduate. With regard to symptomatology and clinical history, responders had significantly lower baseline depression severity scores. In general, comorbid anxiety, substance abuse, and personality disorders did not influence rates of response. However, the presence of depressive personality traits was associated with a higher nonresponse rate. Among psychosocial variables, longer duration of personal relationships as well as higher baseline quality of life were associated with positive response. A stepwise logistic multiple regression identified 5 variables-living with spouse or partner, higher educational level, passive-aggressive personality, lower introverted-tense personality traits, and higher quality of life--that significantly and independently contributed to the predictive model. This model correctly classified 67% of patients. CONCLUSION: A higher baseline quality of life, living with spouse or partner, and having more education were the strongest predictors of response to acute pharmacotherapy among chronically depressed patients. Clinical variables and comorbidity were not identified as independent predictors, although personality traits did appear to influence treatment response. Overall, the predictive value of these baseline measures was modest, and therefore of limited clinical utility.

Hallucinogens, serotonin and obsessive-compulsive disorder.

The serotonin (5-HT) neurotransmitter system has been implicated in the pathophysiology of several neuropsychiatric disorders, especially obsessive-compulsive disorder (OCD). Blockade of 5-HT reuptake appears to be an important initial neurobiological event in the therapeutic mechanism of action of antiobsessional drugs. However, for reasons that continue to be poorly understood, clinical improvement following initiation of treatment with 5-HT reuptake inhibitors can take up to eight to 12 weeks, and most patients do not fully improve. Recent data suggest that activation of 5-HT2A and/or 5-HT2C receptors may be important for the improvement of OCD symptoms. Most psychedelic drugs are potent agonists at 5-HT2A and 5-HT2C receptors and their binding potency to these receptors is strongly correlated with their human potency as hallucinogens. This article will briefly review the relevant clinical and preclinical studies relating to the effects of hallucinogens on OCD. These data suggest that activation of 5-HT2 receptors by hallucinogens may lead to acute reduction of, as well as possible longer-lasting beneficial effects on, the symptoms of OCD. Evidence for and against involvement of 5-HT2A and/or 5-HT2C receptors in the therapeutic effects of drug therapies for OCD are reviewed. Issues related to the pharmacological properties and safety of psychedelic drugs, when considered as potential treatments for patients with OCD, are summarized. The authors suggest that controlled trials of potent 5-HT2 agonists in people suffering from OCD are warranted.

Pindolol augmentation of treatment-resistant depressed patients.

BACKGROUND: Recent uncontrolled reports describe a dramatic and rapid improvement of depressive symptoms in patients treated with the combination of pindolol and serotonin selective reuptake inhibitors or monoamine oxidase inhibitors. The present study attempts to replicate those findings. METHOD: Ten outpatients with current DSM-III-R major depressive disorder who had failed to obtain or maintain an appropriate response to an adequate trial of antidepressant drug were included in a randomized double-blind, placebo-controlled, crossover study. Subjects received pindolol 2.5 mg p.o. t.i.d. or placebo for 2 weeks in addition to their current antidepressant. Clinical monitoring, vital signs, and behavioral ratings were performed weekly for the duration of the study. RESULTS: Pindolol was well tolerated by all patients. None of the subjects experienced significant symptom worsening during the addition of either placebo or active drug. At the end of the 2-week trial, there was no statistically significant difference between pindolol augmentation and placebo. Two patients had a categorical response during placebo treatment. No categorical responses were observed during pindolol augmentation. CONCLUSION: This study failed to replicate the rapid and dramatic response to pindolol augmentation in treatment-resistant depressed patients.

Effects of alpha-methyl-para-tyrosine (AMPT) in drug-free depressed patients.

A variety of biologic studies have demonstrated abnormal regulation of the norepinephrine (NE) system in patients with major depression, suggesting a role for NE in the etiology of depression. Brain NE and dopamine levels can be rapidly reduced by blocking synthesis with the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine (AMPT). In the current investigation, AMPT was administered to drug-free depressed patients to evaluate the effect on mood of diminished catecholamine levels. Seventeen drug-free patients meeting DSM-III-R criteria for major depressive episode were tested with AMPT and an active placebo control, diphenhydramine. Testing was accomplished in a double-blind, crossover fashion, with random assignment to test conditions. Each test included baseline evaluation, 2 days with administration of either AMPT or diphenhydramine, and a follow-up day. Diphenhydramine was used as an active control because of the significant sedation associated with AMPT. Behavioral ratings, including visual analogue scales for a variety of feeling states, the Hamilton Depression Rating Scale (HDRS), and plasma for 3-methoxy-4-hydroxyphenelethyleneglycol (MPHG) and homovanillic acid (HVA) levels, were obtained. AMPT significantly reduced plasma HVA by 70% and MHPG by 50%, but it had no significant effects on the HDRS. AMPT also significantly increased visual analogue ratings of "tired" and decreased ratings of "energetic." Diphenhydramine significantly decreased HDRS scores, but the change was small and was not clinically apparent. The lack of AMPT effects on depressed mood, in conjunction with a prior report that large reductions in plasma tryptophan do not systematically alter depressed mood, indicate that monoamine deficiency by itself is insufficient explanation of the cause of depression. The role of the noradrenergic system needs to be considered in relationship to the many other neurobiologic factors that could be involved in the pathophysiology of depression.

Clinical and biochemical effects of catecholamine depletion on antidepressant-induced remission of depression.

BACKGROUND: Most hypotheses of the therapeutic mechanism of action of antidepressant drugs have focused on the role of the monoamines. We examined the effect of catecholamine depletion on antidepressant-induced remission. METHOD: The tyrosine hydroxylase inhibitor alpha-methylparatyrosine and the antihistamine diphenhydramine hydrochloride were administered, during separate test sessions, to depressed patients in remission maintained with either norepinephrine reuptake inhibitors (desipramine [n = 7] or mazindol [n = 2]) or serotonin reuptake inhibitors (fluoxetine hydrochloride [n = 9] or sertraline hydrochloride [n = 1]). Because of considerable sedation associated with alpha-methylparatyrosine testing, diphenhydramine was used as an active control rather than an inactive placebo. The effects of alpha-methylparatyrosine and diphenhydramine on depression, anxiety, and plasma catecholamine metabolites were assessed. RESULTS: alpha-Methylparatyrosine produced similar significant decreases in plasma 3-methoxy-4-hydroxyphenylethyleneglycol and homovanillic acid levels in the treatment groups. alpha-Methylparatyrosine produced a robust increase in depressive symptoms on the Hamilton Depression Rating Scale, including depressed mood, decreased concentration, anhedonia, loss of interest, and feelings of worthlessness, helplessness, and hopelessness, in the desipramine-mazindol but not in the fluoxetine-sertraline group. Diphenhydramine had no effects on mood in either treatment group. CONCLUSIONS: The therapeutic effects of norepinephrine reuptake inhibitors, but not serotonin reuptake inhibitors, are reversed by catecholamine depletion. Considered with previous reports that serotonin depletion produces depressive relapses in patients in remission maintained with serotonin reuptake inhibitors, but not norepinephrine reuptake inhibitors, these findings suggest that antidepressants may not work via a single monoamine-related mechanism.