Antidepressant use over time in a rural older adult population: the MoVIES Project

Do self-referent metacognition and residential context predict depressive symptoms across late-life span? A developmental study in an Italian sample

OBJECTIVES

There is controversial evidence concerning the variables favoring depression in community-dwelling elderly individuals. This study mainly investigates the impact of lifestyle, residential environment, cognitive efficiency and social desirability in predicting self-assessed depressive signs in late adult span.

METHOD

One hundred forty-nine elders were recruited in Northern Italy and Sardinia - an Italian island characterized by the longevity of people living in the inner areas. Participants were presented a battery of questionnaires assessing cognitive efficiency and self-referent measures of depression, metacognition and social desirability.

RESULTS

A hierarchical regression analysis showed that residential environment was the most effective predictor of depressive symptoms, along with gardening and spending time for hobbies. In contrast, social desirability and metacognitive scores played a minor role in predicting mental health. An analysis of variance showed that Sardinian elders showed fewer signs of depression than age-matched elders residing in Northern Italy.

CONCLUSION

The Sardinian residential environment is a strong predictor of preserved mental health in late adulthood. In contrast, self-rated metacognitive efficiency and social desirability play a very marginal role in predicting depression among the elderly.

Characteristics of antidepressant medication users in a cohort of mid-age and older Australians

OBJECTIVES

We aimed to investigate antidepressant use, including the class of antidepressant, in mid-age and older Australians according to sociodemographic, lifestyle and physical and mental health-related factors.

METHODS

Baseline questionnaire data on 111,705 concession card holders aged ⩾45 years from the 45 and Up Study-a population-based cohort study from New South Wales, Australia-were linked to administrative pharmaceutical data. Current- and any-antidepressant users were those dispensed medications with Anatomical Therapeutic Chemical classification codes beginning N06A, within ⩽6 months and ⩽19 months before baseline, respectively; non-users had no antidepressants dispensed ⩽19 months before baseline. Multinomial logistic regression was used to calculate adjusted relative risk ratios (aRRRs) for predominantly self-reported factors in relation to antidepressant use.

RESULTS

Some 19% of the study population (15% of males and 23% of females) were dispensed at least one antidepressant during the study period; 40% of participants used selective serotonin reuptake inhibitors (SSRIs) only and 32% used tricyclic antidepressants (TCAs) only. Current antidepressant use was markedly higher in those reporting: severe versus no physical impairment (aRRR 3.86(95%CI 3.67-4.06)); fair/poor versus excellent/very good self-rated health (4.04(3.83-4.25)); high/very high versus low psychological distress (7.22(6.81-7.66)); ever- versus never-diagnosis of depression by a doctor (18.85(17.95-19.79)); low-dose antipsychotic use versus no antipsychotic use (12.26(9.85-15.27)); and dispensing of ⩾10 versus <5 other medications (5.97(5.62-6.34)). Sociodemographic and lifestyle factors were also associated with use, although to a lesser extent. Females, older people, those with lower education and those with poorer health were more likely to be current antidepressant users than non-users and were also more likely to use TCAs-only versus SSRIs-only.

CONCLUSIONS

Use of antidepressants is substantially higher in those with physical ill-health and in those reporting a range of adverse mental health measures. In addition, sociodemographic factors, including sex, age and education were also associated with antidepressant use and the class of antidepressant used.

Medication use and nonadherence to psychoactive medication for mental health problems by community-living Canadian seniors with depression

OBJECTIVES

To determine the relation between level of depression and psychoactive medication use and nonadherence in Canadian seniors, given that late-life depression is a common, serious mental health problem in Canada.

METHODS

Canadian Community Health Survey-Mental Health and Well-Being respondents aged 65 years and older (n = 7,736) comprised the study sample. Using the Composite International Diagnostic Interview to assess depressive symptoms, we created 4 depression levels to capture a spectrum of depressive disorders and (or) symptoms: major depression, comorbid major depression, depressive symptoms, and no depressive symptoms. Psychoactive medications assessed included sleep aids, anxiolytics, and mood stabilizers and (or) antidepressants (AD). Nonadherence was defined as either not taking medication as recommended or taking medication at a lower dosage than prescribed.

RESULTS

In total, 22.5% of respondents took psychoactive medication for a mental health problem in the previous 12 months. Psychoactive medication use was 46.8% for major depression, 43.1% for comorbid major depression, 34.0% for depressive symptoms, and 17.6% for no depressive symptoms. Rates of psychoactive medication use ranged from 46.5% of those with major depression, to 17.6% of those with no depressive symptoms. Overall, the rate of nonadherence to psychoactive medication was 31%; rates were highest among those with depressive symptoms (37.4%) and lowest among those with no depressive symptoms (27.4%). All 3 depressive categories were associated with greater odds of use and nonadherence.

CONCLUSION

All 3 depression categories were associated with increased use of and nonadherence to psychoactive medication; however, rates of AD and (or) mood stabilizer use for clinically significant depression were low.

Twelve-year depressive symptom trajectories and their predictors in a community sample of older adults

INTRODUCTION

The aim of this study is to understand the long-term course and outcomes of depressive symptoms among older adults in the community by examining trajectories of depressive symptoms over time and identifying profiles of depressive symptoms predicting different trajectories.

METHOD

We measured depressive symptoms biennially for up to 12 years, using the modified Center for Epidemiological Studies-Depression (mCES-D) scale, in 1260 community-based adults aged 65+ years. We determined latent trajectories of total mCES-D scores over time. We identified symptom profiles based on subgroups of baseline depressive symptoms derived from factor analysis, and examined their associations with the different trajectories.

RESULTS

Six trajectories were identified. Two had one or no depressive symptoms at baseline and flat trajectories during follow-up. Two began with low baseline symptom scores and then diverged; female sex and functional disability were associated with future increases in depressive symptoms. Two trajectories began with high baseline scores but had different slopes: the higher trajectory was associated with medical burden, higher overall baseline score, and higher baseline scores on symptom profiles including low self-esteem, interpersonal difficulties, neurovegetative symptoms, and anhedonia. Mortality was higher among those in the higher trajectories.

CONCLUSIONS

In the community at large, those with minimal depressive symptoms are more likely to experience future increases in symptoms if they are women and have functional disability. Among those with higher current symptom levels, depression is more likely to persist over time in individuals who have greater medical burden and specific depressive symptoms.

Factors associated with antidepressant use in depressed and non-depressed community-dwelling elderly: the three-city study

OBJECTIVES

The aim of this study was to identify factors associated with antidepressant use in non-depressed and depressed elderly persons, assuming that they varied according to clinical status.

METHODS

We studied 7,868 French community-dwelling subjects aged 65 years and over. The Center for Epidemiological Studies-Depression scale and the Mini International Neuropsychiatric Interview were used to define three groups: non-depressed, high depressive symptoms and current major depressive disorder. Separate analyses were performed to identify the factors which were associated with antidepressant use in each group.

RESULTS

Antidepressant use (55% selective serotonin re-uptake inhibitors, 25% tricyclic antidepressants, 20% other types) increased from 4.9% in non-depressed subjects to 17.3% in subjects with high depressive symptoms (HDS) and 33.6% of in those with current major depressive disorder (MDD). The factors associated with antidepressant use varied according to depression status. In particular, men with current MDD were more often treated with antidepressants than women whereas, in both the HDS and the non-depressed groups, antidepressant use was, as has been observed elsewhere, more frequent in women. Gender also had a strong modifying effect on the relationship between antidepressant use and history of major depression. Finally, the direction of the association between antidepressant use and cognitive performance varied according to depression status.

CONCLUSIONS

This study showed that the direction and strength of the association between antidepressant use and demographic and health-related factors varied according to the severity of depression symptoms. Further studies are needed to clarify the relationship between gender and cognition and antidepressant use.

WITHDRAWN: Treatment discontinuation with selective serotonin reuptake inhibitors (SSRIs) versus tricyclic antidepressants (TCAs)

BACKGROUND

Selective serotonin reuptake inhibitors are thought to have better discontinuation rates (i.e. less people dropping out) than tricyclic and heterocyclic antidepressant drugs. It is important to quantify the drop-out rates of different antidepressant drugs in order to have a better understanding of the relative tolerability of these drugs.

OBJECTIVES

To assess the comparative tolerability of selective serotonin reuptake inhibitors and tricyclic/heterocyclic antidepressant drugs.

SEARCH STRATEGY

We searched the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Registers (1997 to 1999), MEDLINE (1966 to 1999), EMBASE (1974 to 1999) We also searched specialist journals, the reference lists of relevant papers and previous systematic reviews, conference abstracts and government documents. Representatives of the pharmaceutical industry were contacted.

SELECTION CRITERIA

Parallel group randomised controlled trials comparing selective serotonin reuptake inhibitors with tricyclic or heterocyclic antidepressants in people with depression.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and a third reviewer checked any cases of disagreement.

MAIN RESULTS

We included 136 trials. The selective serotonin reuptake inhibitors showed less participants dropping out compared to the tricyclic/heterocyclic group (odds ratio 1.21, 95% confidence interval 1.12 to 1.30). A statistically significant difference was found in total drop-outs between the selective serotonin reuptake inhibitors and the old tricyclics as well as the newer tricyclics. When the selective serotonin reuptake inhibitors were compared to the heterocyclic antidepressants, there was a non significant difference favouring the selective serotonin reuptake inhibitors. The poor tolerability profile of the old tricyclics was explained by differences in drop-outs for side-effects, but not for inefficacy.

AUTHORS' CONCLUSIONS

Whilst selective serotonin reuptake inhibitors do appear to show an advantage over tricyclic drugs in terms of total drop-outs, this advantage is relatively modest. This has implications for pharmaco-economic models, some of which may have overestimated the difference of drop-out rates between selective serotonin reuptake inhibitors and tricyclic antidepressants. These results are based on short-term randomised controlled trials, and may not generalise into clinical practice.

Prevalence and predictors of depression in populations of elderly: a review

OBJECTIVE

To offer an update on prevalence and predictors of old age depression in populations of elderly Caucasians.

METHOD

The databases MEDLINE and Psychinfo were searched and relevant literature from 1993 onwards was reviewed.

RESULTS

The prevalence of major depression ranges from 0.9% to 9.4% in private households, from 14% to 42% in institutional living, and from 1% to 16% among elderly living in private households or in institutions; and clinically relevant depressive symptom 'cases' in similar settings vary between 7.2% and 49%. The main predictors of depressive disorders and depressive symptom cases are: female gender, somatic illness, cognitive impairment, functional impairment, lack or loss of close social contacts, and a history of depression.

CONCLUSION

Depression is frequent in populations of elderly. Methodological differences between the studies hinder consistent conclusions about geographical and cross-cultural variations in prevalence and predictors of depression. Improved comparability will provide a basis for consistent conclusions.

Bibliometric analysis of biomedical publications on SSRI during 1980-2000

We performed a bibliometric study of the scientific publications referring to selective serotonin reuptake inhibitors (SSRIs). The database used was EMBASE: Psychiatry. We applied the principal bibliometric indicators: Price's and Bradford's laws on the increase or dispersion of scientific literature, Lotka's law on the productivity of authors, the participation index (PaI) of countries, the productivity index (PI) of authors, and the collaboration index. By means of manual coding, documents were classified according to type of study and to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) or nonpsychiatric categories. We analysed 3,622 original documents published between 1980 and 2000. Our results show nonfulfilment of Price's law because production on SSRIs does not grow exponentially (r=0.937 vs. r = 0.946, after linear adjustment). The journal most employed is the Journal of Clinical Psychiatry (Bradford's first zone). The United States is the most productive country (PaI=41.50). The documents were distributed in four groups: experimental pharmacology (8.38%), tolerance and safety (34.94%), clinical efficacy (49.11%), and not specified (7.56%). The drug most studied was fluoxetine (1,745 articles), followed by paroxetine (659). The DSM-IV diagnostic categories most studied were depression (834), obsessive-compulsive disorder (171), and panic disorder (75). The control antidepressants most used in comparative clinical studies were amitriptyline (51) and imipramine (42). The results of the present study show that the SSRIs are not solely antidepressant drugs, but also have a wide range of uses both within the psychiatric sphere (especially in the field of anxiety) and outside it, which explains the considerable scientific production generated in relation to these drugs.

Sociological influences on antidepressant prescribing

This study examined how patient characteristics, physician characteristics, the physician's interaction with the health care system, and the physician's interaction with the patient influenced whether patients with a depression diagnosis received an antidepressant prescription and whether they received a SSRI antidepressant, a non-SSRI antidepressant, or both. The 1998 National Ambulatory Medical Care Survey (NAMCS), in the USA, was used for the analysis. Logistic regression was used to examine what characteristics influenced whether a patient with a depression diagnosis received an antidepressant prescription. Next, a multinomial logistic regression model was applied to examine the relative risk of using one type of antidepressant versus another among antidepressant users while correcting for possible sample selections using the Heckman selection model. Sixty-seven percent of patients with a depression diagnosis received an antidepressant. Patients who were seeing providers who were not primary care physicians or psychiatrists, self-paying patients, and patients with neurotic depression were significantly less likely to receive an antidepressant prescription. Patients with depression listed as their first diagnosis were significantly more likely to receive an antidepressant prescription. Patients seeing a psychiatrist were more likely than patients seeing a primary care physician to receive a non-SSRI antidepressant than a SSRI antidepressant. Patients belonging to an HMO that had capitated visits were over four times more likely to receive non-SSRI antidepressants than SSRI antidepressants. Patients with major depression were significantly more likely to receive a non-SSRI antidepressant. Patients with depression as their primary diagnosis and patients who saw psychiatrists were significantly more likely to receive both SSRI and non-SSRI antidepressants rather than just SSRI antidepressants. Patient characteristics, physician characteristics, the physician's interaction with the health care system, and the physician's interaction with the patient all influenced antidepressant prescribing. An especially important finding was that insurance status influenced whether patients received an antidepressant. Health care providers need to take the time to help patients without insurance obtain antidepressant medication if it is needed.

Prevalence and recognition of depressive symptoms among homebound older adults with urinary incontinence

Within a group of homebound elders with urinary incontinence, the objectives of this study were to (1) examine the prevalence of depressive symptoms, (2) examine the extent to which depression had previously been recognized by health care providers, (3) describe the type and intensity of antidepressant treatment prescribed for subjects, and (4) identify the demographic and functional characteristics associated with depressive symptomatology. A descriptive correlational design was used. The 15-item Geriatric Depression Scale (GDS-15) was administered to 345 homebound adults age 60 years and over referred to a study examining the effectiveness of behavioral therapy for urinary incontinence. Individuals were referred to the study by home care nurses from two large Medicare-approved home health agencies in a large metropolitan county in Pennsylvania. Data were collected during in-home assessments and by chart review. Measures included the GDS-15, structured medical history, in-home review of medications, Older Americans Research and Service Center Physical and Instrumental Activities of Daily Living scales, Mini-Mental State Examination (MMSE), Clock Drawing Test, Performance-Based Toileting Assessment, and bladder diaries. One half of the participants (n = 173; 50.1%) had significant depressive symptomatology, with 35.7% having scores suggesting mild depression and 14.5% severe depression. Only 26.4% and 34.7% of those with mild and severe depressive symptoms, respectively, had a previous diagnosis of depression and only 21.7% and 34.0%, respectively, had been prescribed an antidepressant. The most commonly prescribed class of antidepressants was tricyclic antidepressants, being taken by 9.0% (n = 31) of the total sample, 14 (11.4%) of those with mild symptoms and 4 (8.0%) of those with severe depressive symptomatology. A little over half (60.0%) of subjects being treated with antidepressants continued to exhibit significant depressive symptomatology. Greater dependence in physical activities of daily living, the need for assistance during ambulation, higher MMSE scores, and higher levels of comorbidity were associated (P < .05) with a GDS-15 score of 5 or higher. Depression symptoms are common in homebound older adults with urinary incontinence, but clinical recognition and treatment are limited.

Bupropion SR in the naturalistic treatment of elderly patients with major depression

INTRODUCTION

Bupropion immediate release (IR) and bupropion sustained release (SR) are frequently used to treat geriatric depression, as they have few cardiovascular, gastrointestinal and sexual adverse effects. We sought to examine the efficacy and dosing patterns of bupropion in a naturalistic cohort of elderly subjects with major depression (MD).

METHODS

31 elderly ( > 60 years) patients with unipolar MD (DSM-IV) who were enrolled in Duke's Mental Health Clinical Research Center for the Study of Depression in Later Life were prescribed bupropion SR or IR, alone or in combination with other antidepressant agents, for 12 weeks. Montgomery-Asberg depression rating scale (MADRS) scores and clinical global impression (CGI) severity scores were used to define response.

RESULTS

74% (23/31) of the sample were responders (MADRS < 15) and 53% (16/30) achieved a partial (CGI = 2) or complete (CGI = 1) remission of MD at week 12. Among patients treated with bupropion SR monotherapy, the mean (range) maximal daily dose achieved was 240 mg (150-400 mg). Among those treated with bupropion IR, the mean (range) maximum daily dose achieved was 258 mg (150-450 mg). In subjects on monotherapy, 67% (10/15) of MD subjects were responders (MADRS < 15) and 50% (7/14) achieved full or partial remission. Response rates did not differ statistically among those with high and low medical comorbidity.

CONCLUSIONS

In this naturalistic 12-week study, geriatric MD patients with high and low medical comorbidity responded well to bupropion and bupropion SR. In elderly patients, four to eight week acute treatment periods may be insufficient. Our findings suggest that nearly 50% of elderly depressed subjects at a tertiary center may need combination therapy over the course of their illness. Controlled randomized studies to establish the long-term efficacy and optimal dose of the newer antidepressants in geriatric depression are urgently needed.

Managing late-life depression in primary care practice: a case study of the Health Specialist's role

Complexities in the diagnosis and treatment of late-life depression have stimulated various strategies for assisting the primary care physician to fulfil these tasks more effectively. The role of Health Specialist was developed for this purpose in a study to reduce suicidality among older depressed patients. This role includes clinical and case management tasks which aim to provide the physician with timely, patient-specific information and recommendations. Evolution of this role and its rewards/stressors during the study's first year are described.

Antidepressant prescribing to Hispanic and non-Hispanic white patients in primary care

OBJECTIVE

To examine whether there was a difference in the prescribing of selective serotonin-reuptake inhibitors (SSRIs) and non-SSRI antidepressants to Hispanic and non-Hispanic white patients in primary care.

METHODS

Twenty-seven family practice and internal medicine resident physicians and 407 of their Hispanic and non-Hispanic white patients who were fluent in English or Spanish participated in the study The medical records of all patients were reviewed and information about patient diagnoses and antidepressant prescriptions was abstracted. Logistic regression was used to examine whether Hispanic ethnicity influenced physician prescribing of SSRI and non-SSRI antidepressants while controlling for other patient characteristics and diagnoses. For patients with a diagnosis of depression, logistic regression was used to examine whether Hispanic ethnicity influenced whether patients received antidepressant treatment while controlling for other patient characteristics

RESULTS

Twenty-seven percent of patients received a prescription for one or more antidepressants. Hispanic and non-Hispanic white patients were equally likely to be prescribed SSRI and non-SSRI antidepressant medications. Having a diagnosis of depression and having a diagnosis of chronic pain was significantly correlated with the prescribing of a non-SSRI antidepressant (p < 0.001, p < 0.01, respectively). Having a diagnosis of depression was significantly correlated with the prescribing of an SSRI antidepressant (p < 0.001). Hispanic and non-Hispanic white patients with a diagnosis of depression were equally likely to be prescribed antidepressant treatment. Patients with a diagnosis of depression in the general medicine clinic were significantly less likely to receive antidepressant therapy than patients in the family practice clinic.

CONCLUSIONS

Hispanic ethnicity did not influence antidepressant prescribing. Future research in other settings is needed to further determine whether Hispanic ethnicity influences antidepressant prescribing.

Care for depression in HMO patients aged 65 and older

OBJECTIVE

To examine treatment for depression among older adults in a large staff model health maintenance organization (HMO).

DESIGN

A 4-year prospective cohort study (1989-1993).

SETTING

Four primary care clinics of a large staff model HMO in Seattle, Washington.

PATIENTS

A total of 2558 Medicare enrollees aged 65 and older.

MAIN OUTCOME MEASURES

Treatment of depression was defined as primary care visits resulting in depression diagnoses, use of antidepressant medications, or specialty mental health services.

MAIN RESULTS

The older adults in our sample had low rates of treatment for depression, ranging from 4 to 7% in the entire sample and from 12 to 25% among those with probable depressive disorders. Predictors of treatment included female gender, severity, and persistence of depressive symptoms, and severity of comorbid medical illness. Even when patients were treated for depression, the intensity of treatment was very low. Overall likelihood of treatment for depression increased somewhat from 1989 to 1993, but among those treated, the rate of adequate antidepressant use remained below 30%.

CONCLUSIONS

There is still considerable need to improve care for older adults with depression in primary care.

Selective serotonin reuptake inhibitors versus tricyclic and heterocyclic antidepressants: comparison of drug adherence

BACKGROUND

Selective serotonin reuptake inhibitors are thought to have better discontinuation rates (i.e. less people dropping out) than tricyclic and heterocyclic antidepressant drugs. It is important to quantify the drop-out rates of different antidepressant drugs in order to have a better understanding of the relative tolerability of these drugs.

OBJECTIVES

To assess the comparative tolerability of selective serotonin reuptake inhibitors and tricyclic/heterocyclic antidepressant drugs.

SEARCH STRATEGY

We searched the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Registers (1997 to 1999), MEDLINE (1966 to 1999), EMBASE (1974 to 1999) We also searched specialist journals, the reference lists of relevant papers and previous systematic reviews, conference abstracts and government documents. Representatives of the pharmaceutical industry were contacted.

SELECTION CRITERIA

Parallel group randomised controlled trials comparing selective serotonin reuptake inhibitors with tricyclic or heterocyclic antidepressants in people with depression.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and a third reviewer checked any cases of disagreement.

MAIN RESULTS

We included 136 trials. The selective serotonin reuptake inhibitors showed less participants dropping out compared to the tricyclic/heterocyclic group (odds ratio 1.21, 95% confidence interval 1.12 to 1.30). A statistically significant difference was found in total drop-outs between the selective serotonin reuptake inhibitors and the old tricyclics as well as the newer tricyclics. When the selective serotonin reuptake inhibitors were compared to the heterocyclic antidepressants, there was a non significant difference favouring the selective serotonin reuptake inhibitors. The poor tolerability profile of the old tricyclics was explained by differences in drop-outs for side-effects, but not for inefficacy.

REVIEWER'S CONCLUSIONS

Whilst selective serotonin reuptake inhibitors do appear to show an advantage over tricyclic drugs in terms of total drop-outs, this advantage is relatively modest. This has implications for pharmaco-economic models, some of which may have overestimated the difference of drop-out rates between selective serotonin reuptake inhibitors and tricyclic antdepressants. These results are based on short-term randomised controlled trials, and may not generalise into clinical practice.

Comparison of self-reported and physician-reported antidepressant medication use

PURPOSE

Self-reported medication histories obtained in pharmacoepidemiologic case-control studies are subject to non-differential misclassification and to recall bias. The accuracy of self-reported antidepressant medication use has never been evaluated, but it is important in light of the hypothesis that antidepressant medications may be associated with cancer risk.

METHODS

Within a case-control study of several cancer sites, we compared self-reported antidepressant medication use with antidepressant use recorded in physicians' records. All female cases (n = 147) and controls (n = 119) who reported antidepressant medication use, and a 10% random sample (n = 114) of those who reported no antidepressant use, were asked to provide consent to contact, and the name(s) of their physician(s). These physicians completed a data abstraction form including information on antidepressant prescriptions recorded in patients' medical records.

RESULTS

Substantial agreement was found between subject- and physician-reported antidepressant medication use (kappa = 0.60 [95% confidence interval (CI), 0.47-0.74]; agreement = 80%), and use of specific antidepressant medications (agreement ranged from 82 to 100%), while moderate agreement was observed for duration of use (weighted kappa = 0.56 (95% CI, 0.32-0.79)), and date of first use [weighted kappa = 0.48 (95% CI, 0.23-0.72)]. The level of agreement did not differ markedly between cases and controls, except for duration of use, where agreement was somewhat greater for cases.

CONCLUSIONS

The similar level of agreement among cases and controls suggests that differential misclassification (e.g., recall bias) is unlikely in the reporting of most aspects of antidepressant medication use by women. Furthermore, the overall accurate self-reporting of antidepressant use suggests that there should be minimal non-differential antidepressant exposure misclassification.