Does daily Naikan therapy maintain the efficacy of intensive Naikan therapy against depression?

Authors

Errata

This article is corrected by:

  1. Errata: Erratum Volume 64, Issue 2, 216, Article first published online: 24 March 2010

*Mari Sengoku, PhD, Division of Neuropsychiatry, Department of Multidisciplinary Internal Medicine, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan. Email: sengokumari@live.jp

Abstract

Aim:  Naikan Therapy, which has been applied to treating patients with various mental difficulties, can be classified into two major categories: intensive Naikan therapy, which lasts for seven days in a Naikan center or a clinical institute secluded from the outside world for the purpose of deep introspection, and daily Naikan therapy, which can be integrated into regular daily activities. The aim of this research is to evaluate daily Naikan therapy as a maintenance treatment for depression.

Methods:  Forty-seven patients, who were diagnosed as having major depressive disorder using DSM-IV criteria and who practiced intensive Naikan therapy participated in the present study. Two groups of patients were compared: 24 patients who conducted daily Naikan therapy and 23 patients who did not, after practicing intensive Naikan therapy. To evaluate efficacy, the Beck Depression Inventory was used as a primary outcome measure for the assessment of depression. The State–Trait Anxiety Inventory and the Cornell Medical Index were also used as secondary outcome measures to evaluate anxiety and psychosomatic conditions before, immediately after and three months after intensive Naikan therapy.

Results:  Significant between-group differences were obtained in the time course change of depression, anxiety and psychosomatic scores within three months following the completion of intensive Naikan therapy.

Conclusion:  The current study indicates that conducting daily Naikan therapy is effective for maintaining the psychological and psychosomatic state at 3 months following the intensive Naikan therapy, while a lack of therapy may allow the patients to exacerbate their conditions to the level they held before practicing intensive Naikan therapy.

MAJOR DEPRESSION MAY require long-term treatment because it is a debilitating and recurrent disorder.1 Efficacious alternatives to medication, including psychological intervention, are necessary, especially for patients who may not tolerate or respond to medication. Approximately 40% of patients with depression discontinue their medication within the initial 30 days, and the dropout rate even reaches 72% within 90 days after starting medication.2–4 A meta-analysis study comparing the efficacy between pharmacotherapy and psychotherapy in patients with depression reported that both were about equally effective, whereas the dropout rates seemed to be smaller in psychotherapy compared with pharmacotherapy.5 Moreover, a systematic review comparing both the efficacy and adherence to antidepressant medication use between antidepressant treatment in combination with a psychological intervention and antidepressant treatment alone indicated that the former was associated with a higher improvement rate that the latter.6 In longer therapies, the combination with psychotherapy significantly reduced the dropout rates. However, most studies cited in the above reviews are those from Western countries, and the psychological interventions adopted are cognitive–behavioral therapy, interpersonal psychotherapy, problem-solving therapy and others.

Naikan was established by Ishin Yoshimoto (1916–1988), who was a Jodo Shin Buddhist minister. Naikan literally means ‘looking within’. Naikan was originally rooted in a spiritual practice called Mishirabe, which was practiced among Jodo Shin Buddhist followers in a rural district in Nara, Japan, where Yoshimoto was born. In the practice of Mishirabe, in addition to introspection, the practitioners fasted completely even without liquids, and went without sleep for long periods to reflect on their thoughts and behaviors. What Yoshimoto discovered through this practice was the degree to which his life had been sustained by others, by all living creatures and ultimately by nature instead of only through self-centeredness and, by extension, ignorance. Based on his experience, Yoshimoto realized the possible use of this therapy for all people, not only Buddhist practitioners. So, he established a relatively easier method by eliminating the strict physical restrictions and formed three themes for ‘healthy’ practitioners to be discussed later. Nowadays, the main goal of Naikan is not to achieve religious enlightenment, but to experience self-understanding and self-improvement, goals that can be applied to any person regardless of religion, ethnic group or social background. Naikan therapy (NT) has been adapted to prisons, detention homes, schools and business training. In the field of psychiatry, it has been reported that Naikan as psychotherapy is an efficient means of treating patients with various mental difficulties.7

In intensive Naikan therapy (INT), the patient sits in the corner of a room, walled off by a folding screen to cut off visual stimulation from the outside so that it is easier for them to observe their own thinking. Sitting in a quiet place and staying in a relaxed position, the patient begins to seriously look into his/her thoughts, continuing his/her introspection daily from 06.00 hours to 21.00 hours. The patients examine how they have lived according to three themes: (i) What have I received from a particular person? (ii) What have I returned to that person? and (iii) What troubles and difficulties have I caused that person? To begin with, the patients are asked to examine the relationship with their mothers or their main caretakers through every period of their life, starting from childhood and gradually moving to the present. Then, they are asked to examine themselves regarding other people who are close to them, such as their fathers, spouses, friends, colleagues, and so forth.

In their articles, both Tashiro,8 who studied the efficacy of INT for prolonged depression, and Nukina,9 who presented the efficacy of INT for general anxiety disorders and panic disorders, have referred to the importance of daily Naikan therapy (DNT) as an important factor for preventing the recurrence of various mental disorders, although detailed data have not yet been provided. Yoshimoto, the founder of Naikan, emphasized to his clients that doing DNT for at least one hour a day after completing INT would be highly beneficial.10 He insisted that INT is the preparation for DNT, which should be integrated into daily life. His view was that, although the patients successfully completed INT, their neglect of DNT may cause a quick recurrence of their original perspectives and habits. Yoshimoto's encouragement to do DNT could be explained by his understanding of Dr Ikemi's argument that the neocortex of humans completes its development by the age of 15–16, so the character of each person has generally been formed around that time and is thus very difficult to change. The paleocortex is more fragile and sensitive than the neocortex to various stressful conditions humans are exposed to. These experiences, especially emotional ones experienced by infants through interaction with parents and others, greatly influence the formation of their personalities. The pathetic characteristics of some patients cannot form by experiences and memories from their childhood unless they are recognized and, thus become deeply rooted in their consciousness.11 Therefore, even though patients experience dramatic transformation by practicing INT, by ignoring DNT, they would be drawn to their previous habits and perspectives and may have additional episodes.

The method of DNT for patients who do it for one hour a day is as follows. Patients examine their past as they did in INT. They divide their lives into chronological segments and reflect on themselves in relation to persons important in their lives for half an hour each day as they did in INT. For example, at the end of the day one patient may examine his/her relationship with his/her mother from three to six years for half an hour. Then, the patient may use the remainder of the hour examining his/her day according to the three Naikan themes as follows: (i) What did I receive from others today? (ii) What did I give to others? and (iii) What troubles and difficulties did I cause others today? He/she may then go on to examine a later period of life, for example, four to seven years, on the following day for half an hour, then use the remaining half hour to ask himself/herself the three Naikan themes for that day.

The purpose of this research is to evaluate the efficacy of DNT as a maintenance treatment for depression by comparing patients: (i) who experienced INT and continued DNT, with (ii) those patients who did not conduct DNT after practicing INT. To evaluate efficacy, the Beck Depression Inventory (BDI) was used as a primary outcome measure and the State–Trait Anxiety Inventory (STAI) and the Cornell Medical Index (CMI) were used as secondary outcome measures before, immediately after and three months after INT.

METHODS

Subjects

The subjects were 47 inpatients who were diagnosed as having major depressive disorder through interviews and close examination according to DSM-IV criteria12 by an experienced psychiatrist. All subjects underwent INT at the Midorigaoka Mental Health Clinic between July 2006 and February 2008. The patients with strong suicidal tendencies, paranoia and severe depression requiring psychophysical restraint were excluded. All of the subjects gave written informed consent before participating.

Study design

All subjects had completed INT shortly before they were discharged from the Midorigaoka Mental Health Clinic. Immediately after the completion of INT and at discharge, all patients were advised to practice DNT. However, 24 patients consented to practice daily Naikan (DNT group) while 23 did not (non-DNT group) owing to participant-determined attendance. Fifteen out of 24 patients in the DNT group were admitted to hospital with the aim of undergoing INT for 7 days, which was designated as 8 days for the length of hospitalization. As for the nine patients, they were recommended to practice INT during their stay in the hospital and the average length of hospitalization of these nine patients was 58.3 days. Thirteen out of 23 patients in the non-DNT group were admitted to hospital with the aim of undergoing INT. The rest of the patients were recommended to practice INT during their stay in hospital and the average length of hospitalization of these subjects was 50.2 days. There was no significant between-group difference either in the rate of the patients admitted to hospital with the aim of undergoing INT or the length of hospitalization. Other clinical and demographic backgrounds at baseline for both groups immediately after INT completion are shown in Table 1. All subjects were assessed immediately before and after INT, and after the three months' trial starting shortly after INT completion for depression, anxiety and psychosomatic symptoms severity. The DNT group complied fairly well with the one-hour/day session of DNT within the three months' period and the average rate of practicing the therapy was 3.5 days/week. Twenty-two out of 24 patients in the DNT group were under medication during the trial, which was similar to 22 out of 23 in the non-DNT group.

Table 1.  Clinical and demographic background of the subjects
 DNTnon-DNTP-value
  • Chi-square test.

  • Wilcoxon's rank sum test.

  • BDI, Beck Depression Inventory; CMI-psyche, Cornell Medical Index, psychological; CMI-soma, Cornell Medical Index, somatic; DNT, daily Naikan therapy; INT, intensive Naikan therapy; n.s., not significant; SD, standard deviation; STAI, State–Trait Anxiety Inventory.

Number of subjects2423 
Male subjects916P < 0.05
Mean age (SD)38.5 (11.0)32.7 (12.5)n.s.
Subjects with single episode1617n.s.
Mean years of illness duration (SD)1.7 (1.7)1.7 (1.5)n.s.
Frequency of practicing DNT   
 Everyday30 
 5–6 times per week20 
 3–4 times per week130 
 1–2 times per week60 
Mean BDI scores (SD) before INT25.1 (7.8)25.5 (10.4)n.s.
Mean STAI trait scores (SD) before INT51.0 (12.5)58.5 (13.7)n.s.
Mean STAI state scores (SD) before INT49.5 (12.2)52.7 (17.3)n.s.
Mean CMI-soma scores (SD) before INT27.0 (18.5)40.9 (21.7)P < 0.05
Mean CMI-psyche scores (SD) before INT16.7 (10.8)22.3 (13.5)n.s.

Assessments

  • 1Psychological scales

The BDI,13 the STAI,14 and the CMI15 tests were used for evaluation. The CMI was adopted to observe whether physical functions of patients would be normalized as patients became mentally stable from the perspective of psychosomatic medicine. In cases where NT helped to make patients mentally stable, stress would be alleviated and physical functions would also be normal.16 Therefore, various subjective somatic symptoms (such as hearing, visual, cardiac, respiratory, gastro, dermatological, neural, urological and fatigue symptoms) and subjective psychological symptoms of depression (such as anxiety, tension, hypersensitivity, indignation and inadaptability) may differ between those patients practicing DNT and those not practicing DNT.

  • 2Quality of Naikan: Evaluation after the completion of INT in terms of psychological transformation

It is desirable in NT to recall events in the past by taking another person's perspective along with seriously considering the three already mentioned main themes. As a result, patients may realize that they have received so much love and care from others (feelings of being loved), and will recognize a self-centeredness that they never realized before. When they seriously feel guilt and remorse, they may decide that they would like to discard their ego-centeredness. As discussed above, in terms of psychological transformation, the factors for evaluation are: (i) seeing things from another person's perspective; (ii) the feeling of being loved; (iii) awareness of ego-centeredness; and (iv) the decision to discard ego-centeredness. These four categories are evaluated as shown in Table 2.17

Table 2.  Criteria for evaluation of the four categories of psychological transformation
Psychological transformation Score
Seeing things from another person's perspectiveseeing things only from the patient's perspective0
seeing things objectively without personal emotions1
seeing things from the other person's point of view2
Feelings of being lovedno feelings of being loved0
feelings of being loved1
feelings of being loved unconditionally despite the problems to the person2
Awareness of ego-centerednessno ability to be aware of ego-centeredness0
only aware of ego-centeredness1
awareness of ego-centeredness and remorseful and/or guilty feelings2
Decision to discard ego-centerednessno ability to be aware of ego-centeredness0
only aware of ego-centeredness1
a decision to discard ego-centeredness2

In addition to the above four categories, questions as to whether the patients had a sense of accomplishment and self-acceptance after INT were also added for evaluation.

Data analysis

First between-group differences were tested using χ2-tests for dichotomous variables and Wilcoxon rank sum tests for continuous variables in terms of clinical and demographic backgrounds of the DNT and non-DNT groups. Moreover, assessments regarding psychological transformation after INT were compared between the two groups. In addition, to assure the efficacy of INT for depression, we calculated the remission rate according to the definition of the BDI ≦ 8.18 Next, a repeated ancova measure was performed using the BDI, STAI-trait (T), STAI-state (S), CMI-somatic (soma) and CMI-psychological (psyche) scores as dependent variables; group and sex as interindividual factors; time of assessment (before INT, immediately after INT, 3 months after INT) as an intraindividual factor; and the clinical, demographic and psychological transformation data as covariates if they showed significant between-group differences either before or immediately after INT. For the variables that showed significant interaction between group and time, the difference scores between the first and second assessments (difference-INT) and those between the second and third assessments (difference-DNT) were submitted for secondary ancova.

As depression, anxiety and psychosomatic symptoms are assumed to hold a correlative relationship with each other, the effect of DNT on depression may well be obtained indirectly via its efficacy on anxiety and/or psychosomatic symptoms. With the aim of investigating whether the effect of DNT on depression is independent from its efficacy on anxiety and/or psychosomatic symptoms, we calculated Spearman's rank correlation coefficient between each pair of the difference-DNT variables of BDI, STAI-T, STAI-S, CMI-soma and CMI-psyche scores. Next, in case significant correlations were observed between at least some pairs, we reanalyzed whether significant between-group differences could be obtained in difference-DNT BDI scores, including those variables as covariates that showed a significant relationship with difference-DNT BDI scores in additional ancova.

RESULTS

First, the number of patients that attained the remission criteria immediately after INT was 18 (38.3 %) in total. A significant between-group difference was scored for the number of remitted patients, that is, there were 13 out of 24 patients (54.1%) in the DNT group whereas there were five out of 23 (21.7%) in the non-DNT group (P < 0.05, χ2-test). Next, as there were significant between-group differences in sex, CMI-soma scores assessed before INT, and the scores for ‘feelings of being loved’ and ‘the decision to discard ego-centeredness’ after INT (see Table 3), we adopted the latter three variables as covariates and added sex as an interindividual variable in the following repeated measures ancova.

Table 3.  Comparison of the psychological transformation after INT between the DNT and non-DNT subjects
 DNTnon-DNTP-value
  • Chi-square test.

  • Wilcoxon's rank sum test.

  • DNT, daily Naikan therapy; INT, intensive Naikan therapy; n.s., not significant; SD, standard deviation.

Psychological transformation   
 Seeing things from another person's perspective; mean (SD)2.7 (0.5)2.4 (0.8)n.s.
 Feelings of being loved; mean (SD)2.7 (0.5)2.3 (0.8)P < 0.05
 Awareness of ego-centeredness; mean (SD)2.7 (0.5)2.5 (0.6)n.s.
 Decision to discard ego-centeredness; mean (SD)2.5 (0.7)2.0 (0.7)P < 0.05
 Number of subjects who gained a sense of accomplishment2421n.s.
 Number of subjects who gained a sense of self-acceptance2218n.s.

BDI

There was a significant interaction between group and time (F [2, 80] = 23.31, P < 0.0001) along with a significant main effect of time. The secondary analyses revealed significant between-group differences in both difference-INT (F [1, 40] = 4.79, P < 0.05) and difference-DNT scores (F [1, 40] = 34.72, P < 0.0001) (Fig. 1).

Figure 1.

Comparison of Beck Depression Inventory (BDI) scores between (–◆–) the daily Naikan therapy (DNT) and (–inline image–) non-DNT subjects at pre, post and 3 months following intensive Naikan therapy (INT). INT was conducted for 7 days between ‘pre’ and ‘post’, and DNT for 3 months between ‘post’ and ‘end-point’ for DNT subjects but not for non-DNT subjects. The vertical bars indicate standard deviations. Note the improvement in DNT subjects exceeded that in non-DNT subjects in either difference-INT (pre-post) or difference-DNT (post-end-point) scores.

STAI

For either STAI-T or STAI-S scores, there was a significant interaction between group and time (Table 4). The secondary analyses revealed a significant between-group difference in difference-DNT for either STAI-T (F [1, 40] = 17.71, P < 0.0001) or STAI-S scores (F [1, 40] = 19.49, P < 0.0001), but not in difference-INT scores.

Table 4.  Comparison of secondary outcomes between the DNT and non-DNT subjects at pre, post and 3 months following intensive Naikan therapy
MeasuresGrouptimePrePostEnd-pointAnalysis
  1. Analysis: interaction between time and group in repeated measures ancova.

  2. CMI-psyche, Cornell Medical Index, psychological; CMI-soma, Cornell Medical Index, somatic; DNT, daily Naikan therapy; STAI-S, State–Trait Anxiety Inventory-State; STAI-T, State–Trait Anxiety Inventory-Trait.

STAI-TDNT non-DNT 51.0 (12.5)43.5 (13.5)37.1 (10.3)F (2, 80) = 11.71
58.5 (13.7)51.7 (15.1)58.9 (12.6)P < 0.0001
STAI-SDNT non-DNT 49.5 (12.2)32.0 (9.9)35.2 (11.7)F (2, 80) = 9.24
52.7 (17.3)38.1 (14.8)56.2 (14.6)P < 0.0005
CMI-somaDNT non-DNT 27.0 (18.5)20.9 (18.8)19.4 (16.0)F (2, 80) = 12.92
40.9 (21.7)30.8 (18.6)46.6 (24.0)P < 0.0001
CMI-psycheDNT non-DNT 16.7 (10.8)9.8 (10.9)8.1 (10.1)F (2, 80) = 7.24
22.3 (13.5)16.9 (10.5)24.3 (13.7)P < 0.005

CMI

For either CMI-soma scores or CMI-psyche scores, there was a significant interaction between group and time (Table 4). The secondary analyses revealed a significant between-group difference in difference-DNT for either CMI-soma (F [1, 40] = 22.81, P < 0.0001) or CMI-psyche scores (F [1, 40] = 14.05, P < 0.001), but not in difference-INT scores.

Relationship between difference-DNT BDI, STAI and CMI scores

Spearman's rank correlation coefficient between each pair of the difference-DNT variables of BDI, STAI-T, STAI-S, CMI-soma and CMI-psyche scores revealed that all the pairs showed significant correlations (rho = 0.45–0.70). Additional ancova using difference-DNT BDI scores as dependent variables, including those variables as covariates that showed a significant relationship with difference-DNT BDI scores revealed the non-significant effect of the group (F [1, 36] = 3.27, P < 0.1).

DISCUSSION

Despite the shortcomings in the present study design as noted below, whereas BDI showed significant between-group differences in the improvement during both DNT and INT, significant between-group differences were noted specifically in the DNT phase in terms of STAI and CMI. Therefore, the present findings suggest the efficacy of DNT in preventing the exacerbation of depression by maintaining at least the anxiety and psychosomatic state within three months following the INT. As for depression, as a significant between-group difference was already evident in the INT phase, the possibility cannot be ruled out that the effect of INT was stronger and more extensive in the DNT group than in the non-DNT group. Moreover, an additional analysis testing the effect of DNT on depression using the efficacy of DNT on anxiety and psychosomatic symptoms as covariates suggested the possibility that the effect was indirectly obtained via its efficacy on anxiety and/or psychosomatic state.

It is necessary here to mention the limitations of the present study. Although the definition of ‘maintenance treatment’ has not been firmly established,19 the common consensus understood by professionals refers to a longer period of treatment after the acute symptoms of a disorder have been resolved and the patient has been asymptomatic for at least a six-month period.20 Therefore, a further research using a longer treatment period should be encouraged to confirm the efficacy of DNT as a ‘maintenance’ therapy.

In this study, as the patients themselves decided whether they would practice DNT or not, the subjects were not assigned randomly. The DNT and the non-DNT groups were significantly different in several points of their demographic and clinical background as shown in more women and lower mean CMI-soma scores in the DNT group before INT. Moreover, as compared to the non-DNT group the patients in the DNT group were those that showed a better response to INT, as shown in the improvement of BDI scores and the remission rate defined by BDI, which may well lead to a strong bias to practice DNT. Therefore, it is by no means clear whether DNT is effective or not until a randomized assignment design is adopted. There is a possibility that NT may not be adaptable to some patients' inclination and in such cases, DNT would not work effectively on them as a maintenance therapy either. In addition, we used only subjective questionnaires for the assessment, which might have caused a bias towards the good efficacy for DNT, especially because the subjects in the DNT group decided themselves to practice DNT and were consequently highly motivated. Further studies using a randomized assignment design and objective measurements for assessment are warranted in order to evaluate the accurate efficacy of DNT avoiding any selection biases.

It has been argued that the continuous practice of DNT is not easy. One study showed that at a Naikan center for mentally healthy people, two years after INT, only about half of the practitioners continued DNT.21 Therefore, for patients to practice DNT, they may require strong motivation and discipline for successful treatment. Some device or scheme to conduct DNT more easily should be considered.

NT starts with renewing understanding of others by recollecting memories with other persons' perspectives. Awareness of ego-centeredness and a sense of being loved allows the patient to experience the cognitive transformation from a victim into a person who has been loved and sustained by others. When a person has strong ego-centeredness, he/she becomes inconsiderate, unsatisfied and even criticizes others. This would lead the person into a cycle of bad interpersonal relations and isolate himself/herself from society and cause depression as the result.22 NT juxtaposes the human selfishness and failures that result from our weakness with the caring concern of others and suggests that the natural response to recognition of this discrepancy will be gratitude and a desire to serve others. Thus, the realization of one's own unworthiness, imperfection and sinfulness leads not to the hell of depression but to a positive thankfulness and life purpose.23 Therefore, NT is adequate and recommended to both mentally unhealthy and healthy people, especially to those who have a tendency to blame others, to feel unworthiness and to suffer from poor interpersonal relationships. Also, family members of patients are strongly recommended to practice INT because patients' psychological and social environment should be considered; relationships with parent(s) and spouses may be factors for depressive symptoms in patients.24

On the other hand, in the present study, three patients in the non-DNT group mentioned they were not confident to practice DNT without a Naikan mensetsusha (therapist) as NT tends to focus on negative aspects of their memories and make them feel depressed. For severe cases with depression, especially in case the client tends to blame himself/herself strongly, introduction of INT is inadequate at least until depressive symptoms become relatively stable and signs of strong motivation appear, considering a case report of a patient who attempted suicide during an INT session.25

ACKNOWLEDGMENTS

The authors thank all the participants in this study. We also appreciate the late Dr Ryuzo Kawahara, the founder of the Japanese Naikan Medical Association, who established Kunimi Research Institute of Integrated Medicine and Midorigaoka Mental Clinic, where the therapeutic environment for this research was provided.

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