243
Views
5
CrossRef citations to date
0
Altmetric
Original Research

Impact of depression and social support on nonadherence to antipsychotic drugs in persons with schizophrenia in Thailand

&
Pages 363-368 | Published online: 14 Sep 2010

Abstract

Background:

Little is known about the effect of social support on nonadherence in persons with schizophrenia, especially in developing Asian countries where social support is considered to be imperative. Additionally, the role of depression as a mediator in the association between social support deficits and nonadherence has not been evaluated.

Methods:

This was a cross-sectional study conducted in 75 participants at a university hospital in Thailand. Logistic regression was used to determine whether depression and a deficit in social support were associated with nonadherence, and whether depression mediated this association.

Results:

There were strong relationships between nonadherence and major depressive episodes (odds ratio [OR] 9.5, confidence interval [CI] 2.3–38.9), living alone (OR 21.8, CI 3.5–143.0), and dissatisfaction with support from family (OR 10.0, CI 1.9–53.1). The OR of the association between social support deficits and nonadherence decreased by nearly one half after adjusting for depression.

Discussion:

Depression and social support deficits were significantly associated with nonadherence in persons with schizophrenia. Depression is important in mediating the association between social support deficits and nonadherence. Enhancing social support, as well as early detection and effective intervention for depression should be emphasized in interventions to improve adherence in persons with schizophrenia.

Introduction

Antipsychotic drugs have been proved to be effective in treating persons with schizophrenia, yet nonadherence with the drugs ranges from 20% to 89%.Citation1,Citation2 Nonadherence often leads to negative consequences, including relapse, rehospitalization, poor functional outcomes, and suicide.Citation3,Citation4

Several factors have been found to be associated with nonadherence, including illness-related factors (eg, severity of symptoms, insight, duration of illness), treatment-related factors (eg, type of antipsychotic, side effects), and patient-related factors (eg, stigma, level of education, attitude toward illness, substance abuse).Citation5 Depression has also been recognized as one of the strongest predictors of nonadherence in persons with schizophreniaCitation6 and, in turn, nonadherence with antipsychotic drugs more than triples the suicide risk in these persons.Citation7

Depression is common in the course of schizophrenia. The lifetime prevalence of major depressive episodes in schizophrenia has been estimated to be around 60%, and the point prevalence ranges widely from 10% to 83%, depending on the clinical setting, assessment, duration of study, and characteristics of the study population.Citation8,Citation9 Bartels and Drake categorized depressive symptoms in schizophrenia into three subtypes, ie, depressive symptoms secondary to general medical or substance-related factors, depressive symptoms occurring with acute psychotic episode, and depressive symptoms occurring without acute psychotic symptoms (such as prodromal symptoms, post-psychotic symptoms, and negative symptoms).Citation10

Hudson et al found that lack of social support is one of the most common barriers to adherence reported by persons with schizophrenia,Citation13 although some studies reported insignificant associations between social support and nonadherence.Citation14Citation16 Because the lack of social support from family and neighbors is associated with suicide in persons with schizophrenia,Citation11 depression may mediate the association between social support deficit and nonadherence. Social support deficit may lead to depression via decreased self-esteem, coping skills, and resilience, as well as an increase in experience of stigma.Citation11,Citation12 In Thai culture, which is the focus of this paper, persons with schizophrenia generally live with their family members. Therefore, social support is considered critical for Thai persons with schizophrenia because they receive financial as well as emotional support from the family. However, little is known about the effect of social support on nonadherence in persons with schizophrenia because limited aspects of social support have been studied. Moreover, social support may vary from one culture to another, which may limit comparability of findings across cultures, and modification to measurement strategies might be required.Citation17 In addition, the role of depression in the association between social support deficits and nonadherence in persons with schizophrenia has not been evaluated.

The purposes of this study were to assess the independent association of depression and social support deficit with nonadherence to antipsychotic drugs, and to evaluate the mediating effect of depression on the association between social support deficit and nonadherence to antipsychotic drugs. We hypothesized that depression and social support deficit were independently associated with nonadherence, and that the effect of social support deficit on nonadherence was mediated by depression.

Methods

This was a cross-sectional study conducted at an outpatient clinic of a university hospital in Chiang Mai, Thailand. We estimate the sample size required at 90% power and 5% significance to be 72 participants. Therefore, after approval by the Ethics Committee, Faculty of Medicine, Chiang Mai University, 75 participants were recruited from December 2009 to February 2010. The inclusion criteria were Thai-speaking, aged 18 years or over, diagnosis of schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR),Citation18 and receiving oral antipsychotic drugs. The exclusion criterion was receiving depot antipsychotic within the past month.

We used a clinician-rated visual analog scale (0%–100%) with an 80% cut-off pointCitation4 for evaluating nonadherence in the past month. Major depressive episodes were diagnosed by psychiatrists according to DSM-IV-TR.Citation18 Social support was derived from the scale of six social support deficits (SSDs) which had been found to be highly salient to depression in a previous study.Citation19 These social support deficits were defined as living alone, seeing a relative less often than once a week, lack of reciprocity with neighbours, lack of reciprocity between extended family members, relationship difficulty with one or more relatives, and dissatisfaction with support from family.

The association of nonadherence against each baseline characteristic was analyzed using Chi-square tests and logistic regression (P < 0.05). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression for the association between depression, social support deficits, and nonadherence. The association between social support and nonadherence were reported before and after adjustment for depression to identify the mediating effect of depression. The association between depression and nonadherence were reported before and after adjustment for age, gender, marital status, and income which were chosen a priori as they might associate with depression or nonadherence and, therefore, confound the association.Citation19

Results

Of the 75 participants included in the study, 26 (34.7%) were male, 23 (30.7%) were married, 41 (54.7%) had completed at least high school, and 36 (48.0%) were working. The mean age was 46.8 ± 14.1 years in the adherence group and 42.2 ± 10.6 years in the nonadherence group. The baseline characteristics significantly associated with nonadherence were type of antipsychotic drugs, side effects, and satisfaction with treatment ().

Table 1 Baseline characteristics and nonadherence

The prevalence of nonadherence in the current study was 16.0%. Sixteen percent of the participants had major depressive episodes. Those with major depressive episodes were 9.5 times more likely to be nonadherent to antipsychotic drugs than those without depression before adjustment. The odds association was still significant after adjustment for age, gender, marital status, and income ().

Table 2 The association between depression and nonadherence

Of all persons with schizophrenia, 9.3% lived alone, 13.3% saw a relative less often than once a week, 10.7% reported lack of reciprocity with neighbors, 9.3% felt that members in the family did not care about each other, 12% had experienced upset in a relationship with a relative, and 9.3% were not satisfied with the support they received from their relatives. Two out of the six social support deficits were significantly associated with nonadherence, including living alone and dissatisfaction with support from family. However, after adjustment for depression, the association between dissatisfaction with support from family and nonadherence became nonsignificant. Forty-three percent of the participants had at least one social support deficit. Those with at least one social support deficit were 5.2 times more likely to be nonadherent to antipsychotic drugs than those without a social support deficit. The odds of nonadherence dropped to 3.1 and were not significant after being adjusted for depression ().

Table 3 The association between social support deficits and nonadherence

Discussion

Our study shows that nonadherence to antipsychotic drugs in schizophrenia is a complex and multifactorial phenomenon. The findings confirm the relationship between depression, social support deficit, as well as other factors, including type of antipsychotic drugs, side effects, and satisfaction with nonadherence in persons with schizophrenia.

Depression may lead to nonadherence via impairing cognitive functioning, which affect a person’s ability to follow through with treatment.Citation20,Citation21 Moreover, because positive beliefs in the benefits of treatment are important for adherence, pessimistic thoughts about the illness and loss of faith in treatment which are commonly found in depressed personsCitation11 may lead to nonadherence. Evidence of depression affecting nonadherence has been found in other illnesses, including infectious disease, diabetes, heart disease, and osteoporosis.Citation22Citation25 Because persons with schizophrenia already suffer from negative symptoms, the impact of depression on reducing motivation, which associates with nonadherence,Citation26 might be stronger than in other patient groups.Citation15

Of the six social support deficits, living alone was the strongest factor associated with nonadherence, with the OR as high as over 20; however, the association between living alone and nonadherence decreased by nearly a half after being adjusted for depression. The impact of depression was similar in the association between the number of social support deficits and nonadherence. Taken together, our findings suggest that social support deficits are risk factors for nonadherence in schizophrenia, and that the associations may be partially mediated by depression, thereby adding to the limited knowledge about the relationship between social support, depression, and nonadherence in schizophrenia.

Apart from being mediated by depression, social support deficit may lead to nonadherence directly via decreased coping skills, motivation, and resilience, as well as increased experience of stigma and emotional conflict.Citation12,Citation27 Persons who live alone may lack medication supervision and have difficulty accessing medical care.Citation1 In addition, it was found that lack of support from family might hinder persons with schizophrenia in achieving rehabilitation.Citation28

Our findings are in line with the review by Lacro et al which reported that age, gender, marital status, and duration of illness were not associated with nonadherence.Citation1 About half of Thai persons with schizophrenia in this study received typical antipsychotic drugs. This percentage is higher than in Western countries which mostly use atypical ones.Citation29,Citation30 We found that adherence with atypical antipsychotic drugs was significantly better than with typical ones. This parallels previous studies which found that there was an overall trend toward greater adherence among persons receiving atypical antipsychotic drugs.Citation1,Citation31 Our findings are also consistent with those of a previous study showing that individuals who switched from a typical to an atypical antipsychotic drug were more adherent than those who had their typical antipsychotic drug maintained.Citation32

Typical antipsychotic drugs are more likely to produce extrapyramidal side effects and akathisia, which may directly lead to nonadherence. It is also suggested that typical antipsychotic drugs are depressogenic by blocking dopamine 2 receptorsCitation33 and may lead to nonadherence via depression. Fewer side effects, as well as the effectiveness of atypical antipsychotic drugs in managing psychotic symptoms, might make it more likely that persons will continue their treatment. Thus, the choice of antipsychotic drug affects adherence to those drugs.

This study, in parallel with previous studies,Citation34,Citation35 shows that side effects impact antipsychotic adherence. A study by Yamada et al found that the most common reason for nonadherence in Japanese persons with schizophrenia was “distressed by side effects”.Citation36 In contrast, studies of persons with first-episode schizophrenia reported negative findings.Citation6,Citation37 Perkins et al suggested that stage of illness and experience with antipsychotic side effects may have an impact on the contribution of side effects to nonadherence.Citation6

Although this study leads to a better understanding of the association between nonadherence, social support, depression, and other variables, certain limitations exist. Firstly, the direction of causality among variables cannot be determined due to the cross-sectional study design. It is possible that there might be a vicious cycle whereby depression and social support deficit cause nonadherence which, in turn, worsen depression and social support deficit. In addition, nonadherence may change over time, although some studies have found it to be quite stable.Citation38

Secondly, nonadherence was assessed based on psychiatrist judgment only, so it may have been underestimated. Moreover, psychiatrists’ judgment of adherence may have been biased by the clinical state of the patients.Citation39

Thirdly, it should be borne in mind that the social support deficit scale was developed to assess social support deficit in older adults, and therefore, measurement error might have occurred through the adaptation of the social support deficit scale to a different sample. Moreover, use of a clinician-rated visual analog scale, although easily assessed and commonly used to assess adherence, may have limited validity and underestimated nonadherence. This limitation might explain the relatively low prevalence of nonadherence found in this study and might be the reason why we did not find associations between some of the social support deficit subscale items and nonadherence. However, this would not explain our positive findings.

Fourthly, the small sample size might limit our positive findings and might explain the low frequency of comorbid depression found in this study, although the result is in line with the findings reported in a previous survey in Thailand.Citation40 In addition, research in the hospital setting might lead to selection bias because individuals who are nonadherent are more likely to be lost to follow-up during the treatment process, and the particular sample characteristics from a university hospital in Thailand might reduce generalizability to other persons with schizophrenia in different settings. Future research in a community setting, conducted in a larger number of persons with schizophrenia or other psychotic disorders, is necessary for a better understanding of nonadherence.

In conclusion, this study shows that depression and social support deficits were significantly associated with nonadherence in persons with schizophrenia. Depression is important in mediating the association between social support and nonadherence in persons with schizophrenia. Other baseline characteristics found to be associated with nonadherence were receiving typical antipsychotic drugs, having more than one side effect, and being less satisfied with treatment. Enhancing social support, which is a modifiable factor, should be emphasized in intervention to improve adherence in persons with schizophrenia. Early detection and effective intervention for depression, as well as concern about drug side effects and patient satisfaction might be useful in dealing with nonadherence in persons with schizophrenia.

Disclosure

The authors report no conflicts of interest in this work.

References

  • LacroJPDunnLBDolderCRLeckbandSGJesteDVPrevalence of and risk factors for medication nonadherence in persons with schizophrenia: A comprehensive review of recent literatureJ Clin Psychiatry2002631089290912416599
  • LiebermanJAStroupTSMcEvoyJPEffectiveness of antipsychotic drugs in patients with chronic schizophreniaN Engl J Med2005353121209122316172203
  • VigueraACBaldessariniRJHegartyJDvan KammenDPTohenMClinical risk following abrupt and gradual withdrawal of maintenance neuroleptic treatmentArch Gen Psychiatry199754149559006400
  • DonohoeGOwensNO’DonnellCPredictors of compliance with neuroleptic medication among inpersons with schizophrenia: A discriminant function analysisEur Psychiatry200116529329811514132
  • VelliganDIWeidenPJSajatovicMThe expert consensus guideline series: Adherence problems in persons with serious and persistent mental illnessJ Clin Psychiatry200970Suppl 4146 quiz 7–819686636
  • PerkinsDOGuHWeidenPJMcEvoyJPHamerRMLiebermanJAPredictors of treatment discontinuation and medication nonadherence in persons recovering from a first episode of schizophrenia, schizophreniform disorder, or schizoaffective disorder: A randomized, double-blind, flexible-dose, multicenter studyJ Clin Psychiatry200869110611318312044
  • HeringsRMErkensJAIncreased suicide attempt rate among persons interrupting use of atypical antipsychoticsPharmacoepidemiol Drug Saf200312542342412899119
  • BuckleyPFMillerBJLehrerDSCastleDJPsychiatric comorbidities and schizophreniaSchizophr Bull200935238340219011234
  • MartinRLCloningerCRGuzeSBClaytonPJFrequency and differential diagnosis of depressive syndromes in schizophreniaJ Clin Psychiatry19854611 Pt 29132865255
  • BartelsSJDrakeREDepressive symptoms in schizophrenia: Comprehensive differential diagnosisCompr Psychiatry19882954674833053027
  • RoyAPompiliMManagement of schizophrenia with suicide riskPsychiatr Clin North Am200932486388319944889
  • HardySEConcatoJGillTMResilience of community-dwelling older personsJ Am Geriatr Soc200452225726214728637
  • HudsonTJOwenRRThrushCRA pilot study of barriers to medication adherence in schizophreniaJ Clin Psychiatry200465221121615003075
  • ComptonMTRudischBEWeissPSWestJCKaslowNJPredictors of psychiatrist-reported treatment-compliance problems among persons in routine U.S. psychiatric carePsychiatry Res20051371–2293616223527
  • ElbogenEBSwansonJWSwartzMSvan DornRMedication nonadherence and substance abuse in psychotic disorders: Impact of depressive symptoms and social stabilityJ Nerv Ment Dis20051931067367916208163
  • SapraMVahiaIVReyesPNRamirezPCohenCISubjective reasons for adherence to psychotropic medication and associated factors among older adults with schizophreniaSchizophr Res20081062–334835518851906
  • BroadheadJAbasMSakutukwaGKChigwandaMGaruraESocial support and life events as risk factors for depression amongst women in an urban setting in ZimbabweSoc Psychiatry Psychiatr Epidemiol200136311512211465782
  • American Psychiatric AssociationDiagnostic and Statistical Manual of Mental Disorders4th ed (Text Revision)Washington, DCAmerican Psychiatric Association2000
  • SuttajitSPunpuingSJirapramukpitakTImpairment, disability, social support and depression among older parents in rural ThailandPsychol Med20108111
  • DiMatteoMRLepperHSCroghanTWDepression is a risk factor for noncompliance with medical treatment: Meta-analysis of the effects of anxiety and depression on patient adherenceArch Intern Med2000160142101210710904452
  • WeinbergerMIMateoCSireyJAPerceived barriers to mental health care and goal setting among depressed, community-dwelling older adultsPatient Prefer Adherence2009314514919936156
  • BaneCHughesCMMcElnayJCThe impact of depressive symptoms and psychosocial factors on medication adherence in cardiovascular diseasePatient Educ Couns200660218719316253468
  • MehtaSHThomasDLSulkowskiMSSafaeinMVlahovDStrathdeeSAA framework for understanding factors that affect access and utilization of treatment for hepatitis C virus infection among HCV-mono-infected and HIV/HCV-co-infected injection drug usersAIDS200519Suppl 3S179S18916251816
  • RossiniMBianchiGDi MunnoODeterminants of adherence to osteoporosis treatment in clinical practiceOsteoporos Int200617691492116538553
  • SobelRMMarkovDThe impact of anxiety and mood disorders on physical disease: The worried not-so-wellCurr Psychiatry Rep20057320621215935135
  • WilliamsGCRodinGCRyanRMGrolnickWSDeciELAutonomous regulation and long-term medication adherence in adult outpersonsHealth Psychol19981732692769619477
  • DiMatteoMRSocial support and patient adherence to medical treatment: A meta-analysisHealth Psychol200423220721815008666
  • AquilaRWeidenPJEmanuelMCompliance and the rehabilitation allianceJ Clin Psychiatry199960Suppl 192327 discussion 8–910507277
  • KunoERothbardABRacial disparities in antipsychotic prescription patterns for persons with schizophreniaAm J Psychiatry2002159456757211925294
  • LendertsSKalaliAHBuckleyPGeneric penetration in the retail atypical antipsychotic marketPsychiatry (Edgmont)20107391020436769
  • Ascher-SvanumHZhuBFariesDELacroJPDolderCRPengXAdherence and persistence to typical and atypical antipsychotics in the naturalistic treatment of persons with schizophreniaPatient Prefer Adherence20082677719920946
  • JanssenBGaebelWHaerterMKomaharadiFLindelBWeinmannSEvaluation of factors influencing medication compliance in inpatient treatment of psychotic disordersPsychopharmacology (Berl)2006187222923616710714
  • BressanRACostaDCJonesHMEllPJPilowskyLSTypical antipsychotic drugs – D2 receptor occupancy and depressive symptoms in schizophreniaSchizophr Res2002561–2313612084417
  • LambertMConusPEidePImpact of present and past antipsychotic side effects on attitude toward typical antipsychotic treatment and adherenceEur Psychiatry200419741542215504648
  • PerkinsDOPredictors of noncompliance in persons with schizophreniaJ Clin Psychiatry200263121121112812523871
  • YamadaKWatanabeKNemotoNPrediction of medication noncompliance in outpersons with schizophrenia: 2-year follow-up studyPsychiatry Res20061411616916318875
  • PerkinsDOJohnsonJLHamerRMPredictors of antipsychotic medication adherence in persons recovering from a first psychotic episodeSchizophr Res2006831536316529910
  • Ascher-SvanumHFariesDEZhuBErnstFRSwartzMSSwansonJWMedication adherence and long-term functional outcomes in the treatment of schizophrenia in usual careJ Clin Psychiatry200667345346016649833
  • VelliganDIWangMDiamondPRelationships among subjective and objective measures of adherence to oral antipsychotic medicationsPsychiatr Serv20075891187119217766564
  • SiriwanarangsunPKongsukTArunpongpaisanSKittirattanapaiboonPCharatsinghaAPrevalence of mental disorders in Thailand: A national survey 2003Journal of Mental Health of Thailand2004123178188