Lithium augmentation in sertraline-resistant depression: a preliminary dose-response study

Identifying the neuropsychiatric health effects of low-dose lithium interventions: A systematic review

BACKGROUND

Lithium is widely evidenced for its neuropsychiatric benefits. Advantages of 'sub-therapeutic' doses are increasingly being reported, which is apposite given enduring concerns around adverse effects of 'therapeutic' doses. We aimed to synthesise all available evidence from interventional studies investigating low-dose lithium (LDL) across neuropsychiatric outcomes.

METHODS

Electronic databases were systematically searched to include studies where a group of adult humans were treated with LDL (∼serum level ≤0.6 mmol/L), where data describing a neuropsychiatric outcome were reported either before and after treatment, and/or between lithium and a comparator.

RESULTS

18 articles were examined and grouped according to outcome domain (cognition, depression, mania, and related constructs e.g., suicidality). Significant benefits (versus placebo) were identified for attenuating cognitive decline, and potentially as an adjunctive therapy for people with depression/mania. Across studies, LDL was reported to be safe.

CONCLUSIONS

Despite the paucity and heterogeneity of studies, LDL's apparent pro-cognitive effects and positive safety profile open promising avenues in the fields of neurodegeneration, and augmentation in affective disorders. We urge future examinations of LDL's potential to prevent cognitive/affective syndromes.

Augmentative Pharmacological Strategies in Treatment-Resistant Major Depression: A Comprehensive Review

Treatment resistant depression (TRD) is associated with poor outcomes, but a consensus is lacking in the literature regarding which compound represents the best pharmacological augmentation strategy to antidepressants (AD). In the present review, we identify the available literature regarding the pharmacological augmentation to AD in TRD. Research in the main psychiatric databases was performed (PubMed, ISI Web of Knowledge, PsychInfo). Only original articles in English with the main topic being pharmacological augmentation in TRD and presenting a precise definition of TRD were included. Aripiprazole and lithium were the most investigated molecules, and aripiprazole presented the strongest evidence of efficacy. Moreover, olanzapine, quetiapine, cariprazine, risperidone, and ziprasidone showed positive results but to a lesser extent. Brexpiprazole and intranasal esketamine need further study in real-world practice. Intravenous ketamine presented an evincible AD effect in the short-term. The efficacy of adjunctive ADs, antiepileptic drugs, psychostimulants, pramipexole, ropinirole, acetyl-salicylic acid, metyrapone, reserpine, testosterone, T3/T4, naltrexone, SAMe, and zinc cannot be precisely estimated in light of the limited available data. Studies on lamotrigine and pindolol reported negative results. According to our results, aripiprazole and lithium may be considered by clinicians as potential effective augmentative strategies in TRD, although the data regarding lithium are somewhat controversial. Reliable conclusions about the other molecules cannot be drawn. Further controlled comparative studies, standardized in terms of design, doses, and duration of the augmentative treatments, are needed to formulate definitive conclusions.

Treatment resistant depression: causes and consequences

The Joint winners of the second Merck Essay Prize for 1994 were Drs Andrew Smith and Swaran Singh. Their essays are published below. The number of entries was 15.

Fünfundzwanzig Jahre Lithiumaugmentation

Twenty-five years ago the research group of the Canadian psychiatrist de Montigny reported treating antidepressant-refractory depressive patients successfully by adding lithium to their antidepressant. The report, published in 1981 as an open-label uncontrolled observation of only eight patients, falls short of today's methodological standards, but the treatment method, subsequently known as lithium augmentation, nonetheless was to change profoundly the pharmacological strategies for depressive disorders. The story of its development is remarkable, starting with a strictly theoretical idea conceived by Montigny and his colleagues after animal experiments in the 1970s had revealed that pretreatment with an antidepressant over several weeks led to sensitization of central nervous serotonin receptors. The team postulated that the proserotonergic characteristics of lithium, which had been systematically used as a psychotropic drug since 1949, could thus be used specifically to stimulate these receptors. Lithium augmentation demonstrated its effectiveness in the 1980s and 1990s, first in open-label and later in randomized and placebo-controlled studies. In the late 1990s studies aimed at optimizing its clinical application indicated that lithium augmentation must be administered for at least 2 weeks, with lithium serum levels within the range established for prophylactic treatment and assuming patient response, and that the combination of lithium and antidepressant must be continued as a maintenance therapy for 6 to 12 months. Research has yet to clarify how lithium augmentation actually works. Current results show that in addition to the idea postulated by Montigny, lithium could also have an activating effect on the cortisol axis. Thanks to the sound body of evidence which has accrued in the meantime, lithium augmentation is recommended in most guidelines and treatment algorithms as a main strategy for patients who do not respond to antidepressant monotherapy.

Potentiation strategies for treatment-resistant depression

OBJECTIVE

To review the pharmacological basis of antidepressant potentiation in combination therapy and the clinical evidence for its efficacy.

METHOD

Literature searches were undertaken and the results reviewed.

RESULTS

Treatment-resistant depression is common (15-30%). Various strategies exist for dealing with resistant depression, including pharmacological potentiation, i.e. adding a treatment that itself does not have antidepressant actions but that enhances the efficacy of the original treatment. Lithium, triiodothyronine (T3) and buspirone are the best studied potentiating drugs, although other options include pindolol, dopaminergic agents, second-generation antipsychotics, psychostimulants, hormones and anticonvulsants.

CONCLUSION

Several pharmacological potentiation strategies exist. Whilst good evidence exists for lithium combined with antidepressants, although good results have also been reported with augmentation strategies involving T3 or buspirone.

Medication options in the treatment of treatment-resistant depression

AIM

Less than half of those suffering major depressive episodes achieve remission with the first antidepressant provided and one-third of all patients suffering depression have a chronic condition. Clinical experience indicates that a substantial proportion of patients suffer treatment-resistant depression (TRD). Our aim is to explore the literature reporting the drug treatment of TRD, and to present such information as would be of interest to clinical psychiatrists.

METHOD

Literature searches were conducted using PubMed and entering the words antidepressant, augmentation, combined antidepressants, treatment resistant depression and the names of individual antidepressant medications.

RESULTS

Most authors recommended that TRD should be first approached by reassessing the diagnosis, adding psychotherapy and attending to psychosocial factors. Details of the following pharmacological options were identified: (i) augmentation of the currently employed antidepressant with a medication which is not an antidepressant; (ii) change of antidepressant; and (iii) addition of a second antidepressant to the current antidepressant, or commencement of a combination of two antidepressants.

CONCLUSIONS

When monotherapy provided at the maximum manufacturer-recommended doses for 3-4 weeks has failed to provide remission in depression, the diagnosis should be confirmed, psychotherapy added and psychosocial factors should receive attention. In the sustained absence of remission, a better outcome may be obtained by augmenting the antidepressant, changing from a single-action to a double- or multiple-action drug, or by combining antidepressants.

Lithium augmentation therapy in refractory depression: clinical evidence and neurobiological mechanisms

OBJECTIVE

This systematic review examines the evidence and discusses the clinical relevance of lithium augmentation as a treatment strategy for refractory major depressive episodes. It also examines hypotheses on the mode of action of lithium augmentation, with a focus on serotonin (5-HT) and neuroendocrine systems, and proposes recommendations for future research.

METHOD

We searched the Medline computer database and the Cochrane Library for relevant original studies published in English from January 1966 to February 2003. The key words were as follows: lithium, augmentation strategies, lithium augmentation, major depression, refractory depression, treatment-resistant depression, neuroendocrinology, and serotonin.

RESULTS

Of 27 prospective clinical studies published since 1981, 10 were double-blind, placebo-controlled trials, 4 were randomized comparator trials, and 13 were open-label trials. Five of 9 acute-phase placebo-controlled trials demonstrated that lithium augmentation had substantial efficacy. In the acute-treatment trials, the average response rate in the lithium group was 45%, and in the placebo group, 18% (P < 0.001). One placebo-controlled trial showed the efficacy of lithium augmentation in the continuation-phase treatment. Summarizing the open and controlled data, approximately 50% of patients responded to lithium augmentation within 2 to 6 weeks. Animal studies offer robust evidence that lithium augmentation increases 5-HT neurotransmission, possibly by a synergistic action of lithium and the antidepressant on brain 5-HT pathways.

CONCLUSIONS

Augmentation of antidepressants with lithium is the best-documented augmentation therapy in the treatment of refractory depression. Emerging data from animal studies suggest that the 5-HTergic system is involved in the augmentatory effect of lithium.

Treatment of resistant depression by adding noradrenergic agents to lithium augmentation of SSRIs

OBJECTIVE

To examine the efficacy of second-line augmentation with noradrenergic antidepressants (NAs) in depressed patients who partially responded to lithium augmentation of selective serotonin-reuptake inhibitors (SSRIs).

CASE SUMMARY

Six patients with major depression or double depression (major depression and dysthymia) who were partially responsive to lithium and SSRI treatment were given either bupropion or desipramine, in an open clinical manner. Improvement was determined and rated by a psychiatrist based on clinical judgment guided by the Clinical Global Impression (CGI) improvement scale and by the Global Assessment of Functioning (GAF) as described in Axis V in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.

RESULTS

Among the 6 depressed patients with partial remission (much improved in symptoms and moderate functional improvement: CGI score 2, GAF score 51-60) while taking the SSRI and lithium combination, 2 showed complete remission (very much improved in symptoms and good functioning: CGI 1, GAF 80-100) and 3 achieved near-complete remission (very much improved in symptoms and significant functional recovery: CGI 1, GAF 61-80) when given either bupropion or desipramine. One patient did not show any additional clinical or functional improvement. Second-line augmentation with bupropion was better tolerated than desipramine.

CONCLUSIONS

This clinical observation suggests that second-line augmentation with NAs may be a viable option to optimize recovery in depressed patients with a partial response to lithium augmentation of SSRIs.

Strategies for managing depression refractory to selective serotonin reuptake inhibitor treatment: a survey of clinicians

OBJECTIVE

To examine treatment practices in cases where selective serotonin reuptake inhibitors (SSRIs) are ineffective.

METHODS

We surveyed 801 clinicians (including 630 psychiatrists) attending the Massachusetts General Hospital's annual psychopharmacology review course. Clinicians were presented with a vignette about a patient with depression who had responded partially to an SSRI and were asked to choose among various strategies available to manage this patient.

RESULTS

Of those surveyed, 466 clinicians had been in practice a mean of 16.6 years (SD 10.7). Not all clinicians chose to answer every question. Among 455 respondents, 84% (n = 382) chose to increase the dose of the SSRI, 10% (n = 47) chose augmentation or combination, and 7% (n = 31) opted for switching agents. When asked to switch to another agent, 448 responded, of whom 52% (n = 235) chose a newer antidepressant, 34% (n = 152) chose another SSRI, 10% (n = 44) chose a tricyclic antidepressant (TCA), 2% (n = 8) chose a serotonin norepinephrine reuptake inhibitor (SNRI), 1% (n = 5) chose a monoamine oxidase inhibitor (MAOI), and 1% (n = 4) chose an undefined "other" agent. Among 445 respondents, bupropion was the most widely chosen augmenting agent (30%, n = 134), followed by lithium (22%, n = 98). West coast and Canadian clinicians preferred to switch to another SSRI rather than to a newer antidepressant. Canadian clinicians preferred lithium to bupropion as their first-choice augmenting agent, as did clinicians from academic settings. Clinicians from community, individual practice, or group settings favoured bupropion. More experienced clinicians preferred bupropion as a first-choice augmenter, whereas less experienced ones showed a slight preference for lithium. Canadian clinicians were more likely to use MAOIs as second-line agents.

CONCLUSIONS

Clinicians in this sample often followed strategies different from those recommended in the literature. Bupropion may have an important role in augmentating treatment with SSRIs.

Risk of adverse events with the use of augmentation therapy for the treatment of resistant depression

Augmentation therapy is used for those situations where a patient's depression is either treatment-resistant, or partially and/or insufficiently responsive to treatment. It also may be used to attempt to induce a more rapid treatment response. Using drugs together may increase the risk of adverse effects, through potentiation of existing adverse effects or alterations in plasma concentrations of the drug. It is important that clinicians are aware of potential risks of augmentation therapy. Lithium augmentation of a tricyclic antidepressant is relatively well tolerated and the dangers are no greater than using these medications on their own. There are also no reports of serious adverse events when lithium is added to a monoamine oxidase inhibitor. With lithium augmentation of selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitor (SSRI) therapy there have been case reports of the development of a central serotonin syndrome, and thus caution must exercised. A serious concern when using a tricyclic antidepressant to augment an SSRI is the effect of the SSRI on the cytochrome P450 system and the resulting significant increase in tricyclic antidepressant blood concentrations. Augmentation with thyroid hormones appears to be well tolerated and effective. Case reports and open studies indicate that augmentation with buspirone and the psychostimulants, carbamazepine and valproic acid (valproate sodium) is effective and results in minimal adverse effects. However, there is no empirical evidence supporting these results. Recent work supports the tolerability and efficacy of pindolol augmentation. Considerable caution should be exercised when combining psychotropic drugs. The practitioner should only do so with a full knowledge of the compounds involved and their pharmacological properties.

A review of the use of augmentation therapy for the treatment of resistant depression: implications for the clinician

OBJECTIVE

To critically review the literature on augmentation therapy in resistant depression in order to assist the clinician to make a reasoned choice. Augmentation therapy is defined as the addition of a second agent to an existing antidepressant regimen with the aim of achieving improved clinical response.

METHOD

The available literature which related specifically to currently popular augmentation strategies in treatment resistant depression for the past 20 years was examined. The scientific evidence supporting the efficacy of these regimens and their safety was reviewed.

RESULTS

Considerable research on lithium augmentation has been undertaken, and on triiodothyronine augmentation to a lesser degree. A number of other drugs have been trialed as augmentation agents with claims of success; however, most of the evidence supporting these agents is anecdotal and in the form of case reports. There are very few well-performed double-blind placebo-controlled studies of augmentation therapy.

CONCLUSIONS

Because of possible complex pharmacodynamic and pharmacokinetic interactions, augmentation therapy is not without its potential complications. Lithium augmentation of tricyclic antidepressants can be recommended as a safe and effective strategy and there is a body of scientific evidence supporting the addition of T3 as an effective augmentation agent. Recent research with pindolol augmentation of selective serotonin re-uptake inhibitors (SSRIs) is encouraging, but these findings require replication. There is no empirical evidence supporting buspirone, carbamazepine, sodium valproate, methylphenidate or amphetamine as effective augmentation agents, or that adding a tricyclic to a SSRI has usefulness in relieving depressive symptoms. There is a need for considerable research in this area, with more prospective well-controlled placebo studies.

Selective serotonin reuptake inhibitor-induced serotonin syndrome: review

The selective pharmacology of the selective serotonin reuptake inhibitors (SSRIs) results in a lower potential for pharmacodynamic drug interactions relative to other antidepressants such as the tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs). However, the SSRIs have been implicated in the development of the serotonin syndrome--a potentially life-threatening complication of treatment with psychotropic drugs. The syndrome is produced most often by the concurrent use of two or more drugs that enhance central nervous system serotonin activity and often goes unrecognized because of the varied and nonspecific nature of its clinical features. The serotonin syndrome is characterized by alterations in cognition (disorientation, confusion), behavior (agitation, restlessness), autonomic nervous system function (fever, shivering, diaphoresis, diarrhea), and neuromuscular (ataxia, hyperreflexia, myoclonus) activity. The difference between this syndrome and the occurrence of adverse effects caused by serotonin reuptake inhibitors alone is the clustering of the signs and symptoms, their severity, and their duration. There are important pharmacokinetic interactions between SSRIs and other serotonergic drugs due principally to their effects on the cytochrome P450(CYP) isoenzymes, the potential for which varies widely amongst the SSRI group, which may increase the likelihood of a pharmacodynamic interaction. The exceptionally long washout period required after fluoxetine discontinuation may cause additional problems and/or inconvenience. Patients with serotonin syndrome usually respond to discontinuation of drug therapy and supportive care alone, but they may also require treatment with antiserotonergic agent such as cyproheptadine, methysergide, and/or propranolol. To reduce the occurrence, morbidity, and mortality of the serotonin syndrome, it must be both prevented by prudent pharmacotherapy and given prompt recognition when it is present.

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.

A double-blind, placebo-controlled study of citalopram with and without lithium in the treatment of therapy-resistant depressive patients: a clinical, pharmacokinetic, and pharmacogenetic investigation

Sixty-nine depressive patients (DSM III criteria: 296.2, 296.3, 296.5, 300.4) were treated with 40 to 60 mg citalopram (CIT) daily for 4 weeks. Among them, 45 responded to treatment (improvement > 50% on the 21-item Hamilton Rating Scale for Depression [HAM-D]) and continued their treatment for another week before being released from the study. The 24 nonresponders were randomized and comedicated under double-blind conditions with lithium carbonate (Li) (2 x 400 mg/day) (CIT-Li group) or with placebo (CIT-Pl group) from days 29 to 35. For days 36 to 42, the patients of both subgroups were treated openly with Li (800 mg/day) in addition to the ongoing CIT treatment. On day 35, 6 of 10 patients responded to the CIT-Li combination, whereas 2 of 14 patients only responded to the CIT-Pl combination. This group difference reached significance (p < 0.05) on day 35 with lower HAM-D total scores in the CIT-Li group. No evidence was seen of a pharmacokinetic interaction between CIT and Li, and this combination was well tolerated. Patients were phenotyped with dextromethorphan and mephenytoin at baseline and at day 28. As evaluated at baseline, three patients (responders) were poor metabolizers of dextromethorphan and six patients (three responders and three nonresponders) of mephenytoin. On day 28, the ratio CIT/N-desmethylCIT (DCIT) in plasma was significantly higher in poor than in extensive metabolizers of mephenytoin (p = 0.0001), and there was a significant positive correlation between the metabolic ratio of dextromethorphan and the ratio DCIT/N-didesmethylCIT in plasma (p < 0.001). These findings illustrate the role of CYP2D6 and CYP2C19 in the metabolism of CIT. It can be concluded that Li addition to CIT is effective in patients not responding to CIT alone without any evidence of an accentuation or provocation of adverse events.

Management of treatment-resistant unipolar and chronically depressed patients

The majority of depressed patients presenting as treatment refractory will respond to a properly chosen new medication or to a previous agent administered correctly. Drug combinations are less frequently required than current practice would indicate, and their usage depends at present more on clinical experience than scientific fact. Educating the patient about the series of options available, and the sequence in which they will be undertaken, and imbuing the enterprise with hopeful optimism are essential ingredients to ultimate success.

Management of treatment resistance in the depressed geriatric patient

The treatment of depression in geriatric patients is challenging on all levels. Recognition, compliance, medical comorbidity, tolerance of drug regimens, and accessibility of the patient to therapy all represent major clinical problems. Treating depression in elderly, disabled patients requires patience, keen observation skills, and much flexibility. It is critical that these patients trust their physicians and have ready access if problematic side effects develop. In general, when treating patients with a history of failure to respond, the clinician should choose a medication with a tolerable side-effect profile, and persist with it as long as steady, slow gains are being made. Dosages should be maximized to clinical tolerance prior to considering switching agents or augmentation strategies. It is probably wiser to augment than switch if a partial response has been obtained. Particularly among the medically ill elderly, any "lost ground" may be very difficult to replace. All available psychosocial resources should be assessed and brought to bear productively in the treatment context. We are quite far from a full clinical understanding of "treatment resistance" in elderly depressive patients, but the eminent treatability of depression in elderly patients encourages creative exploration of treatment regimens. Rigorous, placebo-controlled studies of representative samples of elderly patients are needed to clarify the diverse interactions among the many pharmacologic agents available to treat resistant/refractory depression in the elderly.

The treatment of refractory depression using paroxetine with lithium augmentation

1. The case is described of a 68-year-old woman with DSM-III-R major depression who was treatment-resistant to paroxetine. 2. Low dose lithium addition, at a plasma level of 0.2 mM, led to a rapid and sustained remission of her illness.

Treatment approaches to therapy-resistant depression

Resistance to antidepressant treatment is a controversial field and therapy resistance has received a wide range of definitions. The field has suffered from a lack of consensus on how to classify treatment resistance and from the related failure to standardise clinical criteria in trials of new therapeutic approaches. A significant proportion of tricyclic antidepressant (TCA)-resistant depression results from the failure to sustain an adequate course of therapy. This can be due to either inadequate prescribing or the poor tolerability of TCAs. The majority of cases of treatment resistance, however, involve antidepressant therapy at a dose and duration that would normally be expected to be effective. In these cases, therapy may fail for many reasons. Refractory depression may occur in patients with medical conditions such as subclinical hypothyroidism, stroke and closed head injuries. Patients with alcoholism may prove refractory to treatment, as may those receiving certain medications, notably calcium channel blockers. Certain subtypes of depression, such as rapid-cycling disorder and delusional depression, also appear to be more refractory to treatment. A variety of therapeutic approaches have been applied to treatment-resistant depression but, for most of these, placebo-controlled clinical trials with substantial numbers of patients have not been conducted. Selective serotonin re-uptake inhibitors (SSRIs) may have a role to play in TCA-resistant patients as a result of their superior tolerability; monoamine oxidase inhibitors (MAOIs) also have a significant therapeutic role. ECT has an important role to play in patients who failed to respond to successive drug therapies. Of the various add-on therapies, thyroid augmentation (triiodothyronine) of antidepressant treatment has shown promise, and definite benefits have been established for lithium augmentation. Evidence has emerged to show that lithium is not only effective as an adjunct to TCA therapy, but also to the better tolerated SSRIs. However, further trials will be necessary to determine the optimal dosage and treatment duration for lithium augmentation.

Tolerability of combined treatment with lithium and paroxetine: 19 cases treated under open conditions

Nineteen patients resistant to paroxetine monotherapy were treated by lithium augmentation for 6 weeks to assess tolerability. Although the addition of lithium increased the number of adverse events, none were serious. The combination of lithium and paroxetine is safe enough to warrant further investigation as a treatment for resistant depression.