Current Therapeutic Research 99 (2023) 100728

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Current Therapeutic Research
journal homepage: www.elsevier.com/locate/curtheres

An Acceptance and Commitment Therapy Smartphone Application for
Erectile Dysfunction: A Feasibility Study
Junichi Saito, PhD 1,∗, Hiroaki Kumano, MD, PhD 1,2, Mohammad Ghazizadeh, MD, PhD 3,
Chigusa Shimokawa 3, Hideki Tanemura 3
1

Comprehensive Research Organization, Waseda University, Tokyo, Japan
Faculty of Human Sciences, Waseda University, Saitama, Japan
3
Logos Science Corporation, Tokyo, Japan2

a r t i c l e

i n f oArticle history:
Received 28 March 2023
Accepted 9 November 2023

Key words:
Acceptance and Commitment Therapy
psychogenic erectile dysfunction
smartphone app

a b s t r a c t
Background: Erectile dysfunction (ED) is a multifactorial disorder with both psychogenic and organic
components, but psychosocial factors are usually neglected.
Objective: The purpose of this study was to develop a smartphone application targeting psychosocial
factors of ED and to examine its feasibility, acceptability, and treatment response to determine the parameters for a larger clinical trial.
Methods: In this single-arm feasibility study, 8 participants with situational ED were enrolled. Dr. App,a newly developed smartphone treatment application for patients with psychogenic ED consisting of 8
weekly modules based on Acceptance and Commitment Therapy, was delivered. The primary outcome
was comparison of the International Index of Erectile Function-15 domain scores measured pre- and postintervention.
Results: Six out of 8 participants completed the Dr. App and the post-intervention measures. The
Wilcoxon signed-rank test showed a signiﬁcant change in erectile function (P < 0.05; r = –0.65) and asigniﬁcant trend in intercourse satisfaction (P < 0.10; r = –0.47) and overall satisfaction (P < .10; r = –0.47). Additionally, the reliable change index values were used to calculate the number of participants
for whom a clinically meaningful difference occurred. The results showed that 33.30% of the participants
had clinically meaningful differences in erectile function and 66.70% in intercourse satisfaction and overall satisfaction. On the other hand, no signiﬁcant differences were shown in orgasmic function and sexualdesire.
Conclusions: Findings from this study support the feasibility, acceptability, and potential usefulness ofthe smartphone application targeting psychosocial factors of ED and warrant a larger randomized clinical
trial to conﬁrm the results.
© 2023 The Authors. Published by Elsevier Inc.
This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Introduction
Erectile dysfunction (ED) is a major health problem causing
signiﬁcant distress and negatively inﬂuencing men’s quality of life
and their partners.1 According to the biopsychosocial model, ED
is often multifactorial, combining psychogenic and organic components.2 Nonetheless, the fact is that medical treatments only
manage the organic factors inﬂuencing erectile function and neglect the psychological factors.3 Pharmacological treatment doesn’t∗
Address correspondence to: Junichi Saito, PhD, Comprehensive Research Organization, Waseda University, 2-579-15, Mikajima, Tokorozawa, Saitama 359-1192,
Japan.
E-mail address: tekuteke@aoni.waseda.jp (J. Saito).

respond to all the co-occurring aspects of ED, including anxiety,loss of self-conﬁdence, depressed mood, diﬃculties in a couple’scommunication, relationship disputes, or a partner’s sexual problems.4 This is particularly true when the marital and intrapsychic
components are primarily involved in the pathogenesis of ED.
Internet-based therapy can provide psychological treatment
to men seeking ED treatment but are too afraid or shy to solicit
support in person. A few studies suggest that psychological treatment for ED can be feasible and eﬃcacious when delivered via
internet-based cognitive behavioral therapy.5 , 6 In recent years,
many smartphone apps developed for depression and anxiety haveshown eﬃcacy comparable to in-person treatment,7 but no apps
targeting psychogenic ED have been available. This study aimed
to develop a smartphone application targeting ED’s psychosocial

https://doi.org/10.1016/j.curtheres.2023.100728
0011-393X/© 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

J. Saito, H. Kumano, M. Ghazizadeh et al.

Current Therapeutic Research 99 (2023) 100728

factors and examine its acceptability, feasibility, and treatment
response to determine the parameters for a larger clinical trial.
The hypothesis was that the smartphone application would befeasible and acceptable among this tested group.

fulness, and value clariﬁcation were conducted to increase psychological ﬂexibility. From Module 4 onward, the most effective
program for the participant was automatically selected based on
previous assessments. For example, participants with high anxiety about sexual performance were offered attention training technique.13 On the other hand, participants experiencing poor communication with their partners were offered; for example, sexual
relationship building.14 From Module 6 onward, exposure tasks designed to expose the patient to sexual interaction with their partner were provided.15

Materials and Methods
ParticipantsThis study was approved by the Waseda University Academic
Research Ethical Review Committee. The study was also registeredat the Japanese Clinical Trial registration (No. UMIN0 0 0 047183). A
total of 8 participants were recruited from March 2022 to May
2022 at an outpatient ED clinic in Tokyo, Japan.
The recruitment of patients was through a banner posted at theclinic’s website. The patients with ED interested in participating inthe study visited the clinic and completed the registration to participate. No ﬁnancial incentives were paid for participation in the
study.
Eligibility criteria for participation consisted of the following:
those aged 20 to 59 years and those who meet the diagnostic criteria for situational ED (limited to speciﬁc types of stimulation, situations, or partners) according to Diagnostic and Statistical Manualof Mental Disorders-5 (ie, the experience of at least 1 of the following 3 symptoms in almost all or all [75%–100%] sexual activity:
marked diﬃculty in obtaining an erection during sexual activity,
marked diﬃculty in maintaining an erection until the completionof sexual activity, or marked decrease in erectile rigidity).8
Also, the above symptoms have persisted for approximately 6months and have caused signiﬁcant distress to the individuals.
Those with mild to moderate ED (12–21 points) on the International Index of Erectile Function 5 (IIEF-5) score9 and are capable of morning erection and situational erection. Besides, the exclusive criteria were as follows: those receiving or attending anyother psychological treatment or clinical trials; those with a diagnosis of hypertensive disease, heart disease, cerebrovascular disease, chronic kidney disease, or diabetes mellitus; those with suspicions of alcohol or drug abuse; those whose participation judged
inappropriate for any other reason by their primary care physician.
All participants complained of ED lasting for at least 6 months.
They had no sexual dysfunctions other than situational ED. Informed consent was obtained from each participant before participation in the study.

Measures
Primary outcome
The Japanese version of the IIEF-15 is a 15-item self-reportquestionnaire designed to measure ED and several other dimensions of male sexual functioning, which consist of 5 domains9 :erectile function (EF), intercourse satisfaction (IS), orgasmic function (OF), sexual desire (SD), and overall satisfaction (OS). The primary outcome of this study was a change in the IIEF-15 domainscores from pre- to post-intervention.
Statistical Analysis
This study preferred nonparametric tests due to few samples
and the inability to meet normality assumptions on some IIEF-15
domains. The Wilcoxon signed-rank test was used to determine
the difference between mean values of rank obtained from preand posttest measurements. For each IIEF-15 domain, P < 0.05 wasconsidered statistically signiﬁcant, and P < 0.10 was considered atendency. The effect size was calculated, small, medium, and large
effect power r < 0.20, 20 < r < 50, and r > 50, respectively.16
Additionally, the reliable change index (RCI) was utilized to determine if the changes induced by Dr. App were of clinical signiﬁcance.17 We calculated the proportion of participants with an
RCI ≥1.96. Data were analyzed using IBM SPSS Statistics version 25(IBM-SPSS Inc, Armonk, NY) and HAD18_00218.18
Results
Participant characteristics
A total of 8 participants (mean [SD] age = 42.83 [13.19] years)
were included (Table 1). The participants generally were highly educated, had busy work schedules, and tended to sleep less. All participants were married or had been living with a heterosexual speciﬁc partner. Additionally, they were not taking phosphodiesterase5 inhibitors.
Six participants completed the Dr. App and the postintervention measures (Figure 1). Two participants dropped out
during Modules 1 and 2. Five of the 6 completers responded to thequestionnaire about using Dr. App. Some examples of responses included: “The app was reassuring because there are people otherthan doctors who understand me,” “My relationship with my partner has deepened,” “I had a strong impression of the study so that
I would have preferred something more frank,” and “I would liketo see a pop-up notiﬁcation every day or something to keep me
going.”App description
We developed a new smartphone application targeting psychosocial factors of ED named Dr. App (Logos Science Corp, Tokyo,
Japan). It consists of 8 weekly modules delivered via the Internet. All programs were developed based on Acceptance and Commitment Therapy (ACT).10 , 11 The eﬃcacy of ACT has been evaluated in many randomized controlled trials investigating a broad
range of target conditions.12 The programs were delivered in a variety of ways, including video, audio, chat-bot, freetext, and quiz
formats. These could be completed within 10 to 15 minutes perday. Participants were provided an average of 12 programs. Participant and therapist had no face-to-face or telephone contact during
the treatment. Module 1 provided education on the biopsychosocial factors of ED. In Module 2, education on the psychologicalﬂexibility of ACT was provided. Afterward, by following the stories of ﬁctious ED participants, the participants were able to learn
the relationship between psychological ﬂexibility and ED. During
Modules 1 and 2, participants were also asked to answer various
questionnaires to assess psychosocial factors of ED (eg, depression,anxiety about sexual performance, relationships with sexual partners, and lifestyle). In Module 3, exercises on acceptance, mind-

Primary outcomes
Changes in IIEF-15 domain scores for each participant are
shown in Table 2 and Figure 2. The Wilcoxon signed-rank test
showed a signiﬁcant change in the EF (P < 0.05; r = –0.65) anda signiﬁcant trend in the IS (P < 0.10; r = –0.47) and OS (P <2

J. Saito, H. Kumano, M. Ghazizadeh et al.

Current Therapeutic Research 99 (2023) 100728

Table 1
Demographic characteristics of participants (N = 8).
Characteristic

ResultAge, y∗Marital status†
MarriedNot married
Education† [n, (%)]
High school or higher [n, (%)]
Employment status
Employed
Unemployed
Working†<7 h, 7–9 h>9 h
Smoking†
SmokerFormer smoker, nonsmoker
Drinking†≥7/wk
Nondrinker to <6/wk
Sleeping†
7–9 h<7 h, >9 h
Exercise†≥1/wk
Do not exercise, sometime

42.83 (13.19)∗†

Table 2
Changes in International Index of Erectile Function-15 domains scores for eachparticipant.
Pre (n = 6)
Erectile function
Mean (SD)9.50 (7.94)
Patient 1
3
Patient 4
19
Patient 5
10
Patient 6
19
Patient 7
1
Patient 95Intercourse satisfaction
Mean (SD)3.50 (4.46)
Patient 1
0
Patient 4
9
Patient 5
3
Patient 6
9
Patient 7
0
Patient 90
Orgasmic function
Mean (SD)4.83 (5.30)
Patient 1
0
Patient 4
9
Patient 5
10
Patient 6
10
Patient 7
0
Patient 90Sexual desire
Mean (SD)5.83 (3.12)
Patient 1
4
Patient 4
9
Patient 5
6
Patient 6
10
Patient 7
2
Patient 94Overall satisfaction
Mean (SD)5.66 (1.96)
Patient 1
6
Patient 4
8
Patient 5
6
Patient 6
6
Patient 7
2
Patient 967 (87.50)
1 (12.50)
8 (100)7 (87.50)
1 (12.50)
1 (14.28)
6 (85.72)
1 (12.50)
7 (87.50)
2 (25.00)
6 (75.00)
1 (12.50)
7 (87.50)
3 (12.50)
5 (87.50)

Values are presented as mean (SD).
Values are presented as n (%).

Post (n = 6)

P value

Effect size (r)18.83 (9.70)
20
25
27
27
4
10

0.03

–0.60

7.16 (4.16)
8
12
9
9
0
5

0.10

–0.47

7.00 (3.79)
7
10
10
9
0
6

0.27

–0.31

6.50 (3.20)
6
10
10
7
2
4

0.58

–0.15

7.16 (1.60)
6
10
8
7
6
6

0.10

–0.47

Figure 1. Consolidated Standards of Reporting Trials ﬂow chart of the clinical trial.

0.10; r = –0.47). Additionally, RCI values were used to calculate thenumber of participants for whom a clinically meaningful difference
occurred. The results showed that 33.30% of the participants had
clinically meaningful differences in EF and 66.70% in IS and OS. On
the other hand, no signiﬁcant differences were shown in OF andSD.

Figure 2. Changes in the mean of each International Index of Erectile Function15 (IIEF-15) domain scores for all participants pre- and post-intervention. The
Wilcoxon signed-rank test showed a signiﬁcant change in the erectile function (P< .05; r = –0.65) and a signiﬁcant trend in intercourse satisfaction (P < .10; r = –0.47) and overall satisfaction (P < 0.10; r = –0.47). ∗ The Wilcoxon signed-rank test
(P < 0.05).

(75%) completed the intervention, which is higher than the 8% to
50% completion rate observed for internet-based cognitive behavioral therapy for ED in previous studies.5 , 6 The usefulness of interactivity and personalization with the chat-bot is suggested toincrease engagement with the app.19 Incorporating these elements
into the app may have prevented dropouts.

Discussion
Findings from this study support the potential usefulness of an
ACT smartphone application targeting ED with respect to feasibility, acceptability, and treatment response. Six of the 8 participants
3

J. Saito, H. Kumano, M. Ghazizadeh et al.

Current Therapeutic Research 99 (2023) 100728

A recent systematic review shows psychological treatments
beneﬁt men with psychogenic ED, improving erectile function andoverall sexual satisfaction.20 Although none of these studies included studies using apps, the results of this study suggest thatsimilar effects may be achieved with apps. However, this study
found no effect on the IIEF-15 domain of OF and SD. It might havebeen challenging to improve only psychotherapy for OF and SD because of the greater involvement of biological factors in these domains.
It is generally assumed that ED in men younger than age 40
years is primarily driven by psychosocial factors, whereas ED in
older men would be more biologically based.21 Of the 6 completers, 1 who showed little improvement in IIEF-15 score was in
his late 50s and may not have been eligible for the content of thisapplication.
The Dr. App smartphone intervention has the potential to overcome treatment barriers and increase availability of psychotherapy for patients with psychogenic ED. It may be used alone or in
conjunction with standard pharmacotherapy to enhance the therapeutic effects. The strengths of this study are that it is a feasibility study assessing usability, acceptability, and treatment responseof a newly developed smartphone application for alleviating psychogenic factors of ED. The limitations are the small sample sizeand single-arm design; thus, no conclusion about eﬃcacy and generalizability can be made.

All authors reviewed the manuscript and approved it in its current form and have approved the ordering of authorship. J. Saito
and H. Kumano developed the study design. C. Shimokawa and H.
Tanemura supported collecting the data. J. Saito performed the statistical analysis, drafted the article in whole. H. Kumano and M.
Ghazizadeh made critical contributions to the writing and revisionsof the article.
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Conclusions
This study evaluated the feasibility and acceptability of a smartphone application targeting psychogenic erectile dysfunction basedon acceptance and commitment therapy (ACT). The results showed
a positive effect of this approach to alleviating the psychosocial
factors of ED. A larger randomized controlled trial considering aclinically signiﬁcant effect in each IIEF-15 domain between preand post-intervention is currently being planned to follow the success of this feasibility study and to rigorously evaluate the effectiveness of this innovative smartphone app therapy.
Declaration of Competing Interest
This study was funded by Logos Science Corp Ltd, Tokyo, Japan.
M. Ghazizadeh, C. Shimokawa, and H. Tanemura are members ofLogos Science Corp, Ltd. The authors have indicated that they haveno other conﬂicts of interest regarding the content of this article.
Acknowledgments
The authors thank Dr. Taro Ottomo of Ginza Gin Clinic, Dr.
Kazutaka Terai of Sugiyama Obstetrics and Gynecology, Shinjuku,
Japan, and Dr. Katsuyuki Hirano of Renais Clinic, Tokyo, Japan, forhelp in providing patient recruitment. The authors also thank TIS
Intech Group Inc, Tokyo, Japan, for the development of Dr. App
software.

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