Predictors of response to amine-specific antidepressants

Use of Fluoxetine to Reduce Weight in Adults with Overweight or Obesity: Abridged Republication of the Cochrane Systematic Review

INTRODUCTION

Using fluoxetine is one of many weight loss strategies. A serotonin reuptake inhibitor indicated for depression believed to impact weight control by changing an individual's appetite; however, its benefit-risk ratio is unclear. The aim of this review was to assess the efficacy and safety of fluoxetine in reducing weight in adults with overweight or obesity.

METHODS

We searched Cochrane Library, MEDLINE, Embase, and other databases without language restrictions. Cochrane Collaboration tool and GRADE instrument assessed the risk of bias of randomized controlled trials and certainty of their evidence. We conducted random-effects meta-analyses and calculated the risk ratio/mean difference with 95% confidence intervals for the outcomes.

RESULTS

We included 19 trials (2,216 adults) and found that fluoxetine may reduce weight by -2.7 kg (95% CI -4 to -1.4; p < 0.001) and body mass index by -1.1 kg/m2 (95% CI -3.7 to 1.4), compared with placebo; however, it would cause approximately twice as many adverse events, such as dizziness, drowsiness, fatigue, insomnia, or nausea.

CONCLUSIONS

Although low-certainty evidence suggests that off-label fluoxetine may reduce weight, high-certainty research is needed to be conducted in the future to determine its effects exclusively as well as whether it is useful when combined with other agents. This article is based on a Cochrane Review published in the Cochrane Database of Systematic Reviews 2019, Issue 10, DOI: 10.1002/14651858.CD011688.pub2. Cochrane Reviews are regularly updated as new evidence emerges, and in response to feedback, it should be consulted for the most recent version of the review.

Association between psychomotor disturbance and treatment outcome in psychotic depression: a STOP-PD II report

BACKGROUND

Little is known about the relationship between psychomotor disturbance (PMD) and treatment outcome of psychotic depression. This study examined the association between PMD and subsequent remission and relapse of treated psychotic depression.

METHODS

Two hundred and sixty-nine men and women aged 18-85 years with an episode of psychotic depression were treated with open-label sertraline plus olanzapine for up to 12 weeks. Participants who remained in remission or near-remission following an 8-week stabilization phase were eligible to participate in a 36-week randomized controlled trial (RCT) that compared the efficacy and tolerability of sertraline plus olanzapine (n = 64) with sertraline plus placebo (n = 62). PMD was measured with the psychiatrist-rated sign-based CORE at acute phase baseline and at RCT baseline. Spearman's correlations and logistic regression analyses were used to analyze the association between CORE total score at acute phase baseline and remission/near-remission and CORE total score at RCT baseline and relapse.

RESULTS

Higher CORE total score at acute phase baseline was associated with lower frequency of remission/near-remission. Higher CORE total score at RCT baseline was associated with higher frequency of relapse, in the RCT sample as a whole, as well as in each of the two randomized groups.

CONCLUSIONS

PMD is associated with poorer outcome of psychotic depression treated with sertraline plus olanzapine. Future research needs to examine the neurobiology of PMD in psychotic depression in relation to treatment outcome.

Depression Severity Is Related to Less Gross Body Movement: A Motion Energy Analysis

Psychomotor retardation is a well-known clinical phenomenon in depressed patients that can be measured in various ways. This study aimed to investigate objectively measured gross body movement (GBM) during a semi-structured clinical interview in patients with a depressive disorder and its relation with depression severity. A total of 41 patients with a diagnosis of depressive disorder were assessed both with a clinician-rated interview (Hamilton Depression Rating Scale) and a self-rating questionnaire (Beck Depression Inventory-II) for depression severity. Motion energy analysis (MEA) was applied on videos of additional semi-structured clinical interviews. We considered (partial) correlations between patients' GBM and depression scales. There was a significant, moderate negative correlation between both measures for depression severity (total scores) and GBM during the diagnostic interview. However, there was no significant correlation between the respective items assessing motor symptoms in the clinician-rated and the patient-rated depression severity scale and GBM. Findings imply that neither clinician ratings nor self-ratings of psychomotor symptoms in depressed patients are correlated with objectively measured GBM. MEA thus offers a unique insight into the embodied symptoms of depression that are not available via patients' self-ratings or clinician ratings.

Fluoxetine for adults who are overweight or obese

BACKGROUND

Fluoxetine is a serotonin reuptake inhibitor indicated for major depression. It is also thought to affect weight control: this seems to happen through appetite changes resulting in decreased food intake and normalisation of unusual eating behaviours. However, the benefit-risk ratio of this off-label medication is unclear.

OBJECTIVES

To assess the effects of fluoxetine for overweight or obese adults.

SEARCH METHODS

We searched the Cochrane Library, MEDLINE, Embase, LILACS, the ICTRP Search Portal and ClinicalTrials.gov and World Health Organization (WHO) ICTRP Search Portal. The last date of the search was December 2018 for all databases, to which we applied no language restrictions .

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing the administration of fluoxetine versus placebo, other anti-obesity agents, non-pharmacological therapy or no treatment in overweight or obese adults without depression, mental illness or abnormal eating patterns.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened abstracts and titles for relevance. Screening for inclusion, data extraction and risk of bias assessment was performed by one author and checked by the second. We assessed trials for the overall certainty of the evidence using the GRADE instrument. For additional information we contacted trial authors by email. We performed random-effects meta-analyses and calculated the risk ratio (RR) with 95% confidence intervals (95% CI) for dichotomous outcomes and the mean difference (MD) with 95% CI for continuous outcomes.

MAIN RESULTS

We identified 1036 records, scrutinized 52 full-text articles and included 19 completed RCTs (one trial is awaiting assessment). A total of 2216 participants entered the trials, 1280 participants were randomly assigned to fluoxetine (60 mg/d, 40 mg/d, 20 mg/d and 10 mg/d) and 936 participants were randomly assigned to various comparison groups (placebo; the anti-obesity agents diethylpropion, fenproporex, mazindol, sibutramine, metformin, fenfluramine, dexfenfluramine, fluvoxamine, 5-hydroxy-tryptophan; no treatment; and omega-3 gel). Within the 19 RCTs there were 56 trial arms. Fifteen trials were parallel RCTs and four were cross-over RCTs. The participants in the included trials were followed up for periods between three weeks and one year. The certainty of the evidence was low or very low: the majority of trials had a high risk of bias in one or more of the risk of bias domains.For our main comparison group - fluoxetine versus placebo - and across all fluoxetine dosages and durations of treatment, the MD was -2.7 kg (95% CI -4 to -1.4; P < 0.001; 10 trials, 956 participants; low-certainty evidence). The 95% prediction interval ranged between -7.1 kg and 1.7 kg. The MD in body mass index (BMI) reduction across all fluoxetine dosages compared with placebo was -1.1 kg/m² (95% CI -3.7 to 1.4; 3 trials, 97 participants; very low certainty evidence). Only nine placebo-controlled trials reported adverse events. A total of 399 out of 627 participants (63.6%) receiving fluoxetine compared with 352 out of 626 participants (56.2%) receiving placebo experienced an adverse event. Random-effects meta-analysis showed an increase in the risk of having at least one adverse event of any type in the fluoxetine groups compared with placebo (RR 1.18, 95% CI 0.99 to 1.42; P = 0.07; 9 trials, 1253 participants; low-certainty evidence). The 95% prediction interval ranged between 0.74 and 1.88. Following fluoxetine treatment the adverse events of dizziness, drowsiness, fatigue, insomnia and nausea were observed approximately twice as often compared to placebo. A total of 15 out of 197 participants (7.6%) receiving fluoxetine compared with 12 out of 196 participants (6.1%) receiving placebo experienced depression. The RR across all fluoxetine doses compared with placebo was 1.20 (95% CI 0.57 to 2.52; P = 0.62; 3 trials, 393 participants; very low certainty evidence). All-cause mortality, health-related quality of life and socioeconomic effects were not reported.The comparisons of fluoxetine with other anti-obesity agents (3 trials, 234 participants), omega-3 gel (1 trial, 48 participants) and no treatment (1 trial, 60 participants) showed inconclusive results (very low certainty evidence).

AUTHORS' CONCLUSIONS

Low-certainty evidence suggests that off-label fluoxetine may decrease weight compared with placebo. However, low-certainty evidence suggests an increase in the risk for dizziness, drowsiness, fatigue, insomnia and nausea following fluoxetine treatment.

Is duration of illness really influencing outcome in major psychoses?

BACKGROUND

An increasing number of studies identifies the duration of illness (DI) as an important predictor of outcome in patients affected by major psychoses (MP). The aim of the present paper was to revise medical literature about DI and its effects on MP, focusing in particular on the relationship between DI and outcome with particular reference to treatment response, suicidal risk, cognitive impairment and social functioning.

METHODS

A search in the main database sources has been performed to obtain a comprehensive overview. Studies with different methodologies (open and double-blinded) have been included, while papers considering other variables such as duration of untreated episode/illness were excluded. MP included the diagnoses of schizophrenia, bipolar disorder and major depressive disorder.

RESULTS

Available data show that DI influences treatment response, suicidal risk and loss of social functioning in schizophrenic patients, while results are more controversial with regard to cognitive impairment. In bipolar disorder, a long DI has been associated with less treatment response, more suicidal risk and cognitive impairment, but more data are needed to draw definitive conclusions. Finally, studies, regarding DI of illness and its predictive value of outcome in major depressive disorder show contradictory results.

CONCLUSIONS

DI appears a negative outcome factor particularly for schizophrenia, while with regard to mood disorders, more data are needed to draw definitive sound conclusions.

Psychomotor retardation in depression: a systematic review of diagnostic, pathophysiologic, and therapeutic implications

Psychomotor retardation is a central feature of depression which includes motor and cognitive impairments. Effective management may be useful to improve the classification of depressive subtypes and treatment selection, as well as prediction of outcome in patients with depression. The aim of this paper was to review the current status of knowledge regarding psychomotor retardation in depression, in order to clarify its role in the diagnostic management of mood disorders. Retardation modifies all the actions of the individual, including motility, mental activity, and speech. Objective assessments can highlight the diagnostic importance of psychomotor retardation, especially in melancholic and bipolar depression. Psychomotor retardation is also related to depression severity and therapeutic change and could be considered a good criterion for the prediction of therapeutic effect. The neurobiological process underlying the inhibition of activity includes functional deficits in the prefrontal cortex and abnormalities in dopamine neurotransmission. Future investigations of psychomotor retardation should help improve the understanding of the pathophysiological mechanisms underlying mood disorders and contribute to improving their therapeutic management.

Psychomotor retardation in depression: a systematic review of diagnostic, pathophysiologic, and therapeutic implications

Psychomotor retardation is a central feature of depression which includes motor and cognitive impairments. Effective management may be useful to improve the classification of depressive subtypes and treatment selection, as well as prediction of outcome in patients with depression. The aim of this paper was to review the current status of knowledge regarding psychomotor retardation in depression, in order to clarify its role in the diagnostic management of mood disorders. Retardation modifies all the actions of the individual, including motility, mental activity, and speech. Objective assessments can highlight the diagnostic importance of psychomotor retardation, especially in melancholic and bipolar depression. Psychomotor retardation is also related to depression severity and therapeutic change and could be considered a good criterion for the prediction of therapeutic effect. The neurobiological process underlying the inhibition of activity includes functional deficits in the prefrontal cortex and abnormalities in dopamine neurotransmission. Future investigations of psychomotor retardation should help improve the understanding of the pathophysiological mechanisms underlying mood disorders and contribute to improving their therapeutic management.

Fluoxetine versus other types of pharmacotherapy for depression

BACKGROUND

Depression is common in primary care and is associated with marked personal, social and economic morbidity, thus creating significant demands on service providers. The antidepressant fluoxetine has been studied in many randomised controlled trials (RCTs) in comparison with other conventional and unconventional antidepressants. However, these studies have produced conflicting findings.Other systematic reviews have considered selective serotonin reuptake inhibitor (SSRIs) as a group which limits the applicability of the indings for fluoxetine alone. Therefore, this review intends to provide specific and clinically useful information regarding the effects of fluoxetine for depression compared with tricyclics (TCAs), SSRIs, serotonin-noradrenaline reuptake inhibitors (SNRIs), monoamineoxidase inhibitors (MAOIs) and newer agents, and other conventional and unconventional agents.

OBJECTIVES

To assess the effects of fluoxetine in comparison with all other antidepressive agents for depression in adult individuals with unipolar major depressive disorder.

SEARCH METHODS

We searched the Cochrane Collaboration Depression, Anxiety and Neurosis Review Group Controlled Trials Register (CCDANCTR)to 11May 2012. This register includes relevant RCTs from the Cochrane Central Register of Controlled Trials (CENTRAL) (all years),MEDLINE (1950 to date), EMBASE (1974 to date) and PsycINFO (1967 to date). No language restriction was applied. Reference lists of relevant papers and previous systematic reviews were handsearched. The pharmaceutical company marketing fluoxetine and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

All RCTs comparing fluoxetine with any other AD (including non-conventional agents such as hypericum) for patients with unipolar major depressive disorder (regardless of the diagnostic criteria used) were included. For trials that had a cross-over design only results from the first randomisation period were considered.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two review authors using a standard form. Responders to treatment were calculated on an intention-to-treat basis: dropouts were always included in this analysis. When data on dropouts were carried forward and included in the efficacy evaluation, they were analysed according to the primary studies; when dropouts were excluded from any assessment in the primary studies, they were considered as treatment failures. Scores from continuous outcomes were analysed by including patients with a final assessment or with the last observation carried forward. Tolerability data were analysed by calculating the proportion of patients who failed to complete the study due to any causes and due to side effects or inefficacy. For dichotomous data, odds ratios (ORs) were calculated with 95% confidence intervals (CI) using the random-effects model. Continuous data were analysed using standardised mean differences (SMD) with 95% CI.

MAIN RESULTS

A total of 171 studies were included in the analysis (24,868 participants). The included studies were undertaken between 1984 and 2012. Studies had homogenous characteristics in terms of design, intervention and outcome measures. The assessment of quality with the risk of bias tool revealed that the great majority of them failed to report methodological details, like the method of random sequence generation, the allocation concealment and blinding. Moreover, most of the included studies were sponsored by drug companies, so the potential for overestimation of treatment effect due to sponsorship bias should be considered in interpreting the results. Fluoxetine was as effective as the TCAs when considered as a group both on a dichotomous outcome (reduction of at least 50% on the Hamilton Depression Scale) (OR 0.97, 95% CI 0.77 to 1.22, 24 RCTs, 2124 participants) and a continuous outcome (mean scores at the end of the trial or change score on depression measures) (SMD 0.03, 95% CI -0.07 to 0.14, 50 RCTs, 3393 participants). On a dichotomousoutcome, fluoxetine was less effective than dothiepin or dosulepin (OR 2.13, 95% CI 1.08 to 4.20; number needed to treat (NNT) =6, 95% CI 3 to 50, 2 RCTs, 144 participants), sertraline (OR 1.37, 95% CI 1.08 to 1.74; NNT = 13, 95% CI 7 to 58, 6 RCTs, 1188 participants), mirtazapine (OR 1.46, 95% CI 1.04 to 2.04; NNT = 12, 95% CI 6 to 134, 4 RCTs, 600 participants) and venlafaxine(OR 1.29, 95% CI 1.10 to 1.51; NNT = 11, 95% CI 8 to 16, 12 RCTs, 3387 participants). On a continuous outcome, fluoxetine was more effective than ABT-200 (SMD -1.85, 95% CI -2.25 to -1.45, 1 RCT, 141 participants) and milnacipran (SMD -0.36, 95% CI-0.63 to -0.08, 2 RCTs, 213 participants); conversely, it was less effective than venlafaxine (SMD 0.10, 95% CI 0 to 0.19, 13 RCTs,3097 participants). Fluoxetine was better tolerated than TCAs considered as a group (total dropout OR 0.79, 95% CI 0.65 to 0.96;NNT = 20, 95% CI 13 to 48, 49 RCTs, 4194 participants) and was better tolerated in comparison with individual ADs, in particular amitriptyline (total dropout OR 0.62, 95% CI 0.46 to 0.85; NNT = 13, 95% CI 8 to 39, 18 RCTs, 1089 participants), and among the newer ADs ABT-200 (total dropout OR 0.18, 95% CI 0.08 to 0.39; NNT = 3, 95% CI 2 to 5, 1 RCT, 144 participants), pramipexole(total dropout OR 0.12, 95% CI 0.03 to 0.42, NNT = 3, 95% CI 2 to 5, 1 RCT, 105 participants), and reboxetine (total dropout OR0.60, 95% CI 0.44 to 0.82, NNT = 9, 95% CI 6 to 24, 4 RCTs, 764 participants).

AUTHORS' CONCLUSIONS

The present study detected differences in terms of efficacy and tolerability between fluoxetine and certain ADs, but the clinical meaning of these differences is uncertain.Moreover, the assessment of quality with the risk of bias tool showed that the great majority of included studies failed to report details on methodological procedures. Of consequence, no definitive implications can be drawn from the studies' results. The better efficacy profile of sertraline and venlafaxine (and possibly other ADs) over fluoxetine may be clinically meaningful,as already suggested by other systematic reviews. In addition to efficacy data, treatment decisions should also be based on considerations of drug toxicity, patient acceptability and cost.

Sex-dependent modulation of treatment response

The response to a psychotropic medication reflects characteristics of both the medication and the substrate, ie, the individual receiving the medication. Sex is an individual characteristic that influences all elements of the pharmacokinetic process - absorption, distribution, metabolism, and elimination. The effects of sex on these components of the pharmacokinetic process often counterbalance one another to yield minimal or varying sexual differences in blood levels achieved. However, sex also appears to influence pharmacodynamics, the tissue response to a given level of medication. Consideration by the practitioner of sex as a possible contributing factor to treatment nonresponse will enhance the efficacy and precision of clinical interventions.

Surrogate markers of treatment outcome in major depressive disorder

Major depressive disorder (MDD) is a common medical illness affecting millions worldwide. Despite their widespread use since the 1950s and 1960s, the 'downstream' mechanism by which antidepressants ultimately exert their therapeutic effects remains elusive. In addition, except for a few exceptions such as episode severity and the presence of comorbid Axis-I or Axis-III disorders, biological or clinical characteristics which can accurately quantify the risk of poor treatment outcome are lacking, as are factors which could help patients and clinicians select treatment options that would result in superior outcome. The identification of such markers, termed 'surrogate' markers, could help shed further insights into what constitutes illness and recovery, help identify molecular targets for the development of future antidepressants, and lead the way to the design and refinement of a personalized medicine treatment model for MDD. In the following text, several major areas ('leads') where evidence exists regarding the presence of surrogate markers of efficacy outcome in MDD will be briefly reviewed. Leads include evidence from the role of demographic and clinical factors as surrogate markers, to the role of various biological markers including genotype, brain functional imaging, electroencephalography, dichotic listening, and molecular biology and immunology. The purpose of this work is to focus selectively on areas where there have been findings, as opposed to conducting an exhaustive literature review of studies which have failed to yield any significant breakthrough in our knowledge.

Psychomotor retardation in depression: biological underpinnings, measurement, and treatment

Psychomotor retardation is a long established component of depression that can have significant clinical and therapeutic implications for treatment. Due to its negative impact on overall function in depressed patients, we review its biological correlates, optimal methods of measurement, and relevance in the context of therapeutic interventions. The aim of the paper is to provide a synthesis of the literature on psychomotor retardation in depression with the goal of enhanced awareness for clinicians and researchers. Increased knowledge and understanding of psychomotor retardation in major depressive disorder may lead to further research and better informed diagnosis in regards to psychomotor retardation. Manifestations of psychomotor retardation include slowed speech, decreased movement, and impaired cognitive function. It is common in patients with melancholic depression and those with psychotic features. Biological correlates may include abnormalities in the basal ganglia and dopaminergic pathways. Neurophysiologic tools such as neuroimaging and transcranial magnetic stimulation may play a role in the study of this symptom in the future. At present, there are three objective scales to evaluate psychomotor retardation severity. Studies examining the impact of psychomotor retardation on clinical outcome have found differential results. However, available evidence suggests that depressed patients with psychomotor retardation may respond well to electroconvulsive therapy (ECT). Current literature regarding antidepressants is inconclusive, though tricyclic antidepressants may be considered for treatment of patients with psychomotor retardation. Future work examining this objective aspect of major depressive disorder (MDD) is essential. This could further elucidate the biological underpinnings of depression and optimize its treatment.

Predictors, moderators, and mediators (correlates) of treatment outcome in major depressive disorder

Major Depressive Disorder (MDD) is a prevalent illness that is frequently associated with significant disability, morbidity and mortality. Despite the development and availability of numerous treatment options for MDD, studies have shown that antidepressant monotherapy yields only modest rates of response and remission. Clearly, there is an urgent need to develop more effective treatment strategies for patients with MDD, One possible approach towards the development of novel pharmacotherapeuiic strategies for MDD involves identifying subpopulations of depressed patients who are more likely to experience the benefits of a given (existing) treatment versus placebo, or versus a second treatment. Attempts have been made to identify such “subpopulations, ” specifically by testing whether a given biological or clinical marker also serves as a moderator, mediator (correlate), or predictor of clinical improvement following the treatment of MDD with standard, first-line antidepressants. In the following article, we will attempt to summarize the literature focusing on several major areas (“leads”) where preliminary evidence exists regarding clinical and biologic moderators, mediators, and predictors of symptom improvement in MDD, Such clinical leads will include the presence of hopelessness, anxious symptoms, or medical comorbidity. Biologic leads will include gene polymorphisms, brain metabolism, quantitative electroencephalography, loudness dependence of auditory evoked potentials, and functional brain asymmetry

Predicting the outcome of antidepressants and psychotherapy for depression: a qualitative, systematic review

As treatment outcome in depression varies widely, it is important to understand better the predictive value of particular patient characteristics. However, qualitative systematic reviews of the association between easily identifiable patient characteristics and outcome for commonly used treatment options have been unavailable. This article provides an overview of the consistency of findings on the association between sociodemographic factors and depression characteristics, on the one hand, and outcomes of pharmacotherapy, cognitive-behavioral therapy, and interpersonal/psychodynamic psychotherapy for major depression, on the other. There were no findings indicating that gender was associated with treatment outcome in the case of tricyclic antidepressants. There are some indications that younger patients respond worse to tricyclics, whereas especially women appeared to have better outcomes with modern antidepressants (selective serotonin/norepinephrine reuptake inhibitors). Marital status may be related to better outcome in the case of antidepressants and cognitive-behavioral therapy. Longer duration of depression was identified as a negative predictor, most consistently in psychotherapy. In none of the treatment modalities was recurrence a negative predictor. The relation between severity of depression and outcome appeared to be complex, precluding any straightforward inferences.

Emerging treatments for depression

Established treatments for depression are often effective. However, a significant number of patients show limited or no response. With advancements in the explanation of the underlying neurobiology of depression, several novel therapeutic approaches have been developed. Emerging drug targets include novel monoamine oxidase inhibitors, triple monoamine re-uptake inhibitors, omega-3 fatty acids, melatoninergic agonists and receptor antagonists for corticotropin-releasing factor(1), glucocorticoid, substance-P and NMDA. Developments in therapeutic focal brain stimulation include vagus nerve stimulation, transcranial magnetic stimulation, magnetic seizure therapy and deep brain stimulation. The role of psychotherapy, both as monotherapy and as adjunctive therapy, is an active avenue of investigation. Although data on these treatments are limited, preliminary results are encouraging. A major goal that remains to be achieved is the identification of predictors of response to the various antidepressant treatments that have diverse mechanisms of action.

Antidepressants for depressed elderly

BACKGROUND

Depression is a relatively common experience in older adults. The syndrome is associated with considerable distress, morbidity and service commitment. Approximately two thirds of patients presenting with severe forms will respond to antidepressant treatment and the last twenty years has witnessed a great increase in the number of these drugs. Older, frail people are particularly vulnerable to side effects.

OBJECTIVES

The aims of this review were to examine the efficacy of antidepressant classes, to compare the withdrawal rates associated with each class and describe the side effect profile of antidepressant drugs for treating depression in patients described as elderly, geriatric, senile or older adults, aged 55 or over.

SEARCH STRATEGY

The Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register (CCDANCTR-Studies) was searched (2003-08-13). Reference lists of relevant papers and previous systematic reviews were hand searched for published reports and citations of unpublished studies.

SELECTION CRITERIA

Only randomised controlled trials were included. Trials had to compare at least two active antidepressant drugs in the treatment of depression.

DATA COLLECTION AND ANALYSIS

Reviewers extracted data independently. In examining efficacy, the reviewers assumed that people who died or dropped out had no improvement. Withdrawal rates irrespective of cause and specifically due to side effects were compared between drug classes. Relative risk (RR) for dichotomous data and weighted mean difference for continuous data were calculated with 95% confidence intervals (CI). Qualitative side effect data were reported in terms of ratios of side effects and percentage of patients experiencing specific side effects.

MAIN RESULTS

A total of 29 trials provided data for inclusion in the review. We were unable to find any differences in efficacy when comparing classes of antidepressants. However, as the trials contained relatively small numbers of patients, these findings may be explained by a type two error. Tricyclic antidepressants (TCAs) compared less favourably with selective serotonin reuptake inhibitors (SSRIs) in terms of numbers of patients withdrawn irrespective of reason (RR: 1.24, CI 1.04, 1.47) and number withdrawn due to side effects (RR: 1.30, CI 1.02, 1.64). Subgroup analyses demonstrated that TCA related antidepressants had similar withdrawal rates to SSRIs irrespective of reason of withdrawal (RR: 1.49, CI 0.74, 2.98) or withdrawal due to side effects (RR: 1.07, CI 0.43, 2.70). The qualitative analysis of side effects showed a small increased profile of gastro-intestinal and neuropsychiatric side effects associated with classical TCAs.

AUTHORS' CONCLUSIONS

Our findings suggest that SSRIs and TCAs are of the same efficacy. However, we have found some evidence suggesting that TCA related antidepressants and classical TCAs may have different side effect profiles and are associated with differing withdrawal rates when compared with SSRIs. The review suggests that classical TCAs are associated with a higher withdrawal rate due to side effect experience, although these results must be interpreted with caution due to the relatively small size of the review and the heterogeneity of the drugs and patient populations.

Are there differences in the symptoms that respond to a selective serotonin or norepinephrine reuptake inhibitor?

BACKGROUND

We examined two previously published studies comparing a norepinephrine (NE) selective agent, reboxetine, and a serotonin (5-HT) selective agent, fluoxetine, to determine if these agents have different effects on individual depressive symptoms.

METHODS

Both studies were 8-week, double-blind, comparison studies of men and women with DSM III-R major depression. Within-group effect sizes for individual symptom change on the Hamilton Depression Rating Scale (HAMD) were determined in the observed case samples and in patients for whom the symptom was relatively severe at baseline. We required that any significant differences in one sample be cross-validated in the second.

RESULTS

Two hundred fifty-three subjects in study I and 168 subjects in study II were randomized to reboxetine or fluoxetine. In both samples, depressed mood, decreased interest, and psychic anxiety had the greatest change. Effect sizes for all HAMD symptoms were similar for the two drugs. No difference between groups in one sample was replicated in the second. Among subjects with severe symptoms, no significant differences were cross-validated.

CONCLUSIONS

Reboxetine and fluoxetine appear to have similar effects on depressive symptoms. These data suggest that NE and 5-HT selective antidepressant drugs act through the same final common pathway and challenge the belief that symptom differences are useful for antidepressant selection.

Predictors of antidepressant response: A selective review

Modern antidepressant drugs have response rates in the 65% range. Considerable effort has been made to predict which patients would be more likely to respond to antidepressant treatment. Some progress has been made, more in finding psychological predictors than biological predictors of antidepressant response. In spite of slow progress, these findings have made a valuable contribution towards the understanding of antidepressant response. In future it may be possible for psychiatrists to use a more broad-based approach, tailoring therapies to the clinical profile of individuals.

Role of pharmacogenomics in individualising treatment with SSRIs

The introduction of the SSRIs has significantly transformed the pharmacological treatment of a range of psychiatric disorders. In particular, individuals affected by depression, panic disorder, obsessive-compulsive disorder and social phobia have benefited substantially from their use. Compared with the previous generation of psychotropic drugs, SSRIs offer an improved tolerability to therapy while maintaining a high level of efficacy. Nevertheless, despite these advantages, not all patients benefit from treatment; an appreciable proportion do not respond adequately, while others may react adversely. This necessitates a review of the initial treatment choice, often involving extended periods of illness while a more suitable therapy is sought. Such a scenario could be avoided were it possible to determine the most suitable drug prior to treatment. Several factors are postulated to influence outcome of drug therapy; most recently, pharmacogenetic studies have demonstrated a significant influence of genetic mechanisms on the efficacy of clinically prescribed drugs. This contribution, which is primarily a reflection of alterations in genes that encode drug-metabolising enzymes, drug receptors, transporters and second messengers, may be pertinent to the success of SSRI therapy. Attesting to this potential, studies to elucidate the influence of genetic processes on SSRI efficacy now represent a major focus of pharmacogenetics research. Current evidence emerging from the field suggests that gene variants within the serotonin transporter and cytochrome P450 drug-metabolising enzymes may bear a particular importance, though further corroboration of these findings is still warranted. At the same time, it appears likely that further key participating genes remain to be identified. By comprehensively delineating these genetic components, it is envisaged that this will eventually facilitate the development of highly sensitive protocols for individualising SSRI treatment.

A review of the efficacy of serotonergic and noradrenergic reuptake inhibitors for treatment of major depression

Both norepinephrine and serotonin mediate the effects of antidepressant drugs and a reasonable question is whether the efficacy of these two mechanisms of action is similar. Previous reviews comparing selective serotonergic drugs with tricyclic antidepressants found no differences, but the tricyclic drugs are heterogeneous with respect to mechanism of action. The current review focuses on studies comparing serotonergic agents with antidepressants that act primarily on norepinephrine. The literature was reviewed to identify double-blind, random assignment studies comparing SSRIs and NRIs, with adequate description of methods and outcome. Fifteen studies were identified, which had enrolled a total of over 1500 patients. The rates of response with SSRIs and NRIs, 61.4% and 59.5%, were neither meaningfully nor significantly different. Few predictors of response were identified in these studies. Noradrenergic and serotonergic antidepressants appear to be equally effective. It remains to be determined if they treat the same or different patients.

Neurophysiologic predictors of treatment response to fluoxetine in major depression

Treatment with antidepressants is marked by heterogeneity of response; predicting individual response to any given agent remains problematic. Neuroimaging studies suggest that response is accompanied by physiologic changes in cerebral energy utilization, but have not provided useful markers at pretreatment baseline. Using quantitative EEG (QEEG) techniques, we investigated pretreatment neurophysiologic features to identify responders and non-responders to fluoxetine. In a double-masked study, 24 adult subjects with current major depression of the unipolar type were studied over 8 weeks while receiving fluoxetine (20 mg QD) or placebo. Neurophysiology was assessed with QEEG cordance, a measure reflecting cerebral energy utilization. Response was determined with rating scales and clinical interview. Subjects were divided into discordant and concordant groups based upon the number of electrodes exhibiting discordance. The concordant group had a more robust response than the discordant group, judged by lower final Hamilton Depression (HAM-D) mean score (8.0+/-7.5 vs. 19.6+/-4.7, P = 0.01) and final Beck Depression Inventory (BDI) mean score (14.0+/-9.4 vs. 27.8+/-3.7, P = 0.015), and by faster reduction in symptoms (HAM-D: 14.0+/-5.0 vs. 23.8+/-4.1, P = 0.004 at 1 week). Groups did not differ on pretreatment clinical or historical features. Response to placebo was not predicted by this physiologic measure. We conclude that cordance distinguishes depressed adults who will respond to treatment with fluoxetine from those who will not. This measure detects a propensity to respond to fluoxetine and may indicate a more general responsiveness to antidepressants.

Do noradrenaline and serotonin differentially affect social motivation and behaviour?

In a placebo-controlled 8-week study comparing the selective noradrenaline re-uptake inhibitor (NARI), reboxetine, with the selective serotonin reuptake inhibitor (SSRI), fluoxetine, in major depression, patient social motivation and behaviour were investigated through a newly developed 21-item self-rating scale, the Social Adaptation Self-evaluation Scale (SASS). At last assessment the mean SASS total score was significantly superior on both reboxetine (n = 103) and fluoxetine (n = 100) compared with on placebo (n = 99). In addition, the SASS total score in the reboxetine group was significantly higher compared with the fluoxetine group. At point-biserial correlation analysis, all but one item discriminated reboxetine from placebo, while only 12 items discriminated fluoxetine from placebo. In the reboxetine-fluoxetine comparison, nine items showed a positive association with reboxetine, while the opposite was never seen; the association was maximal in the area of negative self perception and lack of motivation towards action. These results support, at social functioning level, a differential effect of selective manipulation of the noradrenergic or serotonergic system in keeping with the long-debated hypothesis on the specific involvement of serotonin in regulating mood and of noradrenaline in sustaining drive.

Predicting outcome of lithium added to antidepressants in resistant depression

This study was conducted to assess the predictive value of different variables including the response to dexamethasone suppression test (DST), in 105 patients with resistant depression after the addition of lithium (600 to 800 mg/day) for 4 weeks to antidepressant medication. Clinical remission was observed in 57 patients and no improvement in 48. A dramatic and rapid relief of depression occurred in 12 patients. Variables with significant or marginally significant differences between responders and non-responders were included in a stepwise logistic regression model. Weight loss (P = 0.0013) and depressive psychomotor activity (P = 0.045) in the Newcastle diagnostic index (NDI) scale, and overall score of the Hamilton Rating Scale for Depression (HRSD) before adding the lithium (P = 0.0039) were significantly associated with clinical remission. The difference in post-DST cortisol plasma levels between both groups was marginally significant. The logistic equation resulted in a sensitivity of 78% and a specificity of 65% and total correct classification of the lithium-added response of 72%. The clinical profile of patients who improve with the addition of lithium may include significant weight loss, psychomotor retardation and possibly, poor control of cortisol secretion. Partial remission before adding lithium as well as endogenomorphic traits according to NDI may also be considered additional criteria for response.