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Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363 Mini review
© Medicinska naklada - Zagreb, Croatia
EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY:
A META-ANALYSIS
Cătălin Zaharia1, Melita Reiner2 & Peter Schütz3
1Mind Master Association, Bucharest, România
2Croatian-Austrian Training Center for NLPt, Russanova, Zagreb, Croatia
3Oesterreichisches Training Zentrum fuer NLP&NLPt, Widerhofergasse, Vienna, Austria
received: 23.7.2015; revised: 28.9.2015; accepted: 5.10.2015
SUMMARY
Background: Neuro Linguistic Programming (NLP) Framework has enjoyed enormous popularity in the field of applied
psychology. NLP has been used in business, education, law, medicine and psychotherapy to identify people’s patterns and alter their
responses to stimuli, so they are better able to regulate their environment and themselves. NLP looks at achieving goals, creating
stable relationships, eliminating barriers such as fears and phobias, building self-confidence, and self-esteem, and achieving peak
performance. Neuro Linguistic Psychotherapy (NLPt) encompasses NLP as framework and set of interventions in the treatment of
individuals with different psychological and/or social problems. We aimed systematically to analyse the available data regarding the
effectiveness of Neuro Linguistic Psychotherapy (NLPt).
Subjects and methods: The present work is a meta-analysis of studies, observational or randomized controlled trials, for
evaluating the efficacy of Neuro Linguistic Programming in individuals with different psychological and/or social problems.
The databases searched to identify studies in English and German language:
CENTRAL in the Cochrane Library;
PubMed;
ISI Web of Knowledge (include results also from Medline and the Web of Science);
PsycINFO (including PsycARTICLES);
Psyndex;
Deutschsprachige Diplomarbeiten der Psychologie (database of theses in Psychology in German language),
Social SciSearch;
National library of health and two NLP-specific research databases: one from the NLP Community
(http://www.nlp.de/cgi-bin/research/nlprdb.cgi?action=res_entries) and one from the NLP Group
(http://www.nlpgrup.com/bilimselarastirmalar/bilimsel-arastirmalar-4.html#Zweig154).
Results: From a total number of 425 studies, 350 were removed and considered not relevant based on the title and abstract.
Included, in the final analysis, are 12 studies with numbers of participants ranging between 12 and 115 subjects. The vast majority of
studies were prospective observational. The actual paper represents the first meta-analysis evaluating the effectiveness of NLP
therapy for individuals with social/psychological problems. The overall meta-analysis found that the NLP therapy may add an
overall standardized mean difference of 0.54 with a confidence interval of CI=[0.20; 0.88].
Conclusion: Neuro-Linguistic Psychotherapy as a psychotherapeutic modality grounded in theoretical frameworks,
methodologies and interventions scientifically developed, including models developed by NLP, shows results that can hold its ground
in comparison with other psychotherapeutic methods.
Key words: Neuro Linguistic Programming – Neuro Linguistic Psychotherapy - treatment effectiveness - meta-analysis -
systematic review
* * * * *
INTRODUCTION
Neuro-Linguistic Programming (NLP) originated in
California around 1974. In the initial group consisted of
a number of Master Degree and Ph.D. students leaded
by the forefront figures of the linguist John Grinder,
Ph.D., the psychology student Richard Bandler and
teacher and psychologist Frank Pucelik. The intention
was to create a methodology for modelling that would
lead to a set of intervention models and techniques. NLP
quickly became popular because many of its practi-
tioners believed the techniques to be extremely efficient
and applicable in different life contexts. An aggressive
marketing was used to help it spread. NLP had repea-
tedly been criticized for its partly unethical and self-
referential claims, its lack of well regulated, while at the
same time very often commercialized, training struc-
tures and lack of proof of valid results.
A number of studies tested the general claims of
NLP and reports different levels of validity scientific
structure (Witkowski 2009, Wake et al. 2012). NLP
started as a method studying and coding in an accessible
format the patterns of very efficient ways of thinking
and communication processes. The collected samples of
the behavior of the most successful people seen from
the perspective of the system theory and cybernetics
give as an output a better interventional strategy. Then
those results allow to be then easily replicated in the
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363
356
work of practitioners with the clients. The early li-
terature promoted approaches generated by NLP metho-
dologies with demonstrable impact as a rapid form of
psychological therapy. An NLP Practitioner will pri-
marily use words to manipulate thoughts and inner
sensory processes in a psychotherapeutic setting. These
kind of interventions are used and accepted in various
psychotherapeutic settings. Cognitive Behavioural The-
rapy (Dryden & Golden 1986), Rational Emotive The-
rapy (Ellis & Grieger 1977) or Acceptance and Com-
mitment Therapy (Hayes & Strosahl 2004) are among
them.
As a psychotherapy modality, NLPt is based prima-
rily on neurobiological, phenomenologically-systemic
and metatheoretical considerations. It can be defined as
a systemic imaginative method of psychotherapy with
an integrative cognitive approach (Schuetz et al. 2001).
NLPt draws on the principles and techniques of NLP,
with a standard EAP referenced the curriculum for
psychotherapeutic education (see www.eanlpt.org) and
a professional code of ethics www.europsyche.org).
Regarding the use of Neuro-Linguistic Psycho-
therapy for clients with psychological difficulties and
perceived quality of life, Stipancic et al. 2010 showed
that NLPt is an efficient intervention. Another study
was performed in with claustrophobic patients who
required MRI (magnetic resonance imaging); NLPt also
proved to be was effective in reducing the need for
general anaesthesia (Bigley et al. 2010). Krugman et al.
1985 indicated that the NLP single-session treatment for
phobias compared with an intervention of self-control
desensitization of equal duration, or a waiting-list
control condition was less efficient in reducing public
speaking anxiety. Also, they mentioned that the
perceived rapid effectiveness of NLP, which was
reported by Bandler and Grinder 1979, was possibly an
artefact of changes that is possibly present without the
interventions that they describe. For this reason, it is
still not clear if there is an efficacy of NLPt in reducing
different social or/and psychological problems.
AIM AND OBJECTIVE
This meta-analysis aims to evaluate all available
data regarding the effectiveness of Neuro Linguistic
Psychotherapy (NLPt) and Neuro Linguistic Program-
ming (NLP) for the treatment of individuals with
different psychological and/or social problems.
SUBJECTS AND METHODS
Inclusion and exclusion methodology
A literature search selected all randomized con-
trolled trials, cohort studies (with or without a com-
parison group), comparative and case-control studies. It
evaluated the relationship between NLPt and effec-
tiveness as described by the authors (with any pre-
specified tools included) and survival/mortality.
Types of participants
Individuals selected are suffering from phobias,
anxiety disorders, morning sickness, depression, allergy.
Types of intervention
The search included the following measurement:
NLP interventions: visualization, anchoring techni-
ques, the visual-kinesthetic dissociation;
Measures of outcomes assessment: Spielberger`s
State-Trait Anxiety Inventory, Personal Report of
Confidence as a Speaker, Structured clinical interviews
for DSM-IV Personality Disorders, Beck Depression
Inventory.
Types of outcome measures
The searched outcome was the efficacy of NLPt as
reported by the authors.
Searching Strategy
For purposes of our search in biographic databases
we used certain strategies to retrieve studies that
contained combined medical subject headings and text
words for NLP and NLPt. We did not apply any
methodological filters or put any restriction on
language. The search strategies are available to read in
Table 1.
The studies identified for inclusion in this review, in
July 2014, were searched in:
CENTRAL in the Cochrane Library;
MEDLINE from 1950;
EMBASE from 1980;
PsychINFO from 1967;
Reference lists of textbooks;
Review studies;
Relevant articles.
In order to to identify any further studies not
retrieved by electronic search we checked the reference
lists of all potentially worthy studies as full reports. We
also obtained full reports of review articles retrieved by
the search and checked these for other relevant citations.
Checking of the methodological quality
The quality of the included studies was evaluated by
the authors. The Newcastle-Ottawa Scale (NOS) for
assessing quality of non-randomized studies was used
(www.lri.ca).
Extraction of data
The authors extracted data from the studies, using a
data extraction form. Each author double-checked data
extraction and data entry independently, and any
discrepancies between authors were resolved by
discussion.
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363
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Table 1. Search Strategies
Database Search terms used
CENTRAL in the
Cochrane Library
MEDLINE from 1950
EMBASE from 1980
PsychINFO from 1967
*Neurolinguistic Programming
Neurolinguistic Programming
*Psycholinguistics
*Psycholinguistics
*NLP
*Psychotherapy
psychotherap*
NLPt*
NLP*
Neuro$linguistic
neurolinguistic.mp. (mp=ti, ab, tx, ct, sh, ot, nm, hw, kf, px, rx, an, ui)
NLP.mp. (mp=ti, ab, tx, ct, sh, ot, nm, hw, kf, px, rx, an, ui)
neurolinguistic programming.mp. (mp=ti, ab, tx, ct, sh, ot, nm, hw, kf, px, rx, an, ui)
psychotherap* near nlp.mp. (mp=ti, ab, tx, ct, sh, ot, nm, hw, kf, px, rx, an, ui)
psychotherap* near programming.mp. (mp=ti, ab, tx, ct, sh, ot, nm, hw, kf, px, rx, an, ui)
Data analysis
The overall effect size was calculated using Cohen’s
d in a random-effect model that is more comparable to
real-world data than a fixed-effect model (Hedges &
Vevea 1998). Sensitivity analysis was performed by
omitting each study once and calculating the overall
effect size again. The publication bias computed using
several methods. The inspection of the funnel plot was
done visually. Rosenthal’s and Orwin’s Fail-safe N was
computed. Begg and Mazumdar’s r. rank correlation, as
well as Egger’s regression test, was performed, and
finally a trim-and-fill analysis (Duval & Tweedie 2000)
was inspected. For all computations, CMA (Compre-
hensive Meta-Analysis v2.2.057) was used.
Effect size calculation
It was decided to use a mean difference expressed in
standard deviation units (Cohen’s d) for calculation
since the therapy effect was considered to be measured
best using this kind of index.
RESULTS
Inclusion-exclusion criteria (Figure 1)
We identified a total number of 425 studies of which
350 were removed and considered not relevant based on
title and abstract. We did find three other records through
searching additional sources or any unpublished data.
We identified 76 potentially relevant citations that
were full-text reviewed. 64 studies we further excluded
for the following reasons:
Not the right population: studies conducted on heal-
thy individuals with social/psychological problems
(n=19);
Not the right intervention (n=17): studies conducted
in healthy individuals with social/psychological pro-
blems (n=8), depression (n=5), other (n=4);
Not the good outcome: studies carried out in healthy in-
dividuals with social/psychological problems (n=17);
Excluded based on study design (n=11): review,
editorial, comment letter, study design protocol.
Overall, we finally included 12 studies with a total
number of individuals of 658 (studies that analysed
different subgroups from the same population). On
average, the numbers of participants in each study was
small, ranging between 12 and 115 subjects (see Table
2, Figure 1).
A study (Bigley et al. 2010) measured the level of
anxiety in 50 participants with claustrophobia using
Magnetic Resonances Investigation. The selected sub-
jects were 24 males, 26 females with a median age of 52
years. The result showed that the anxiety scores
significantly reduces after NLP sessions during the MRI
examination. The MR radiographer (therapist) attended
a 20 days training in NLP techniques (accredited by the
International NLP Trainers Association). The main NLP
technique used was “Clare`s fast phobia cure”, and
applied in one-hour duration. The patient`s level of
anxiety was assessed with Spielberger`s State – Trait
Anxiety Inventory.
In another study, Krugman et al. included a number
of 55 undergraduate students (28 male and 27 female)
with anxiety in public speaking situations. NLP single-
session treatment for phobias was not giving better
results in reducing public speaking anxiety than
another psychotherapeutic interventions (Krugman et
al. 1985). The therapists were three graduate students
trained in NLP treatment for phobias. The therapists
used kinaesthetic anchoring techniques and visua-
lization in one single session. Before the subjects
began their speeches, they rated their anxiety level,
using a 12 items questionnaire derived from the Report
of Confidence as a Speaker, developed by Gilkinson,
1942. Also, during their speeches, three trained
observers rated the subjects` behavioural anxiety using
Paul`s (1966) Behavioral Checklist- 10-point scale.
After speech delivery, the subjects indicated the level
of anxiety using the same Report of Confidence as a
Speaker.
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363
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Table 2. Baseline characteristics of the included studies
Study
(reference) Type of study No Age (mean) Gender Psychological and/or social problem
Allen 1982 Randomized
Controlled Trial 36 32 F
4 M Snake phobia
Bigley
et al. 2010 Prospective
observational 50 Median age 52
(range 17-75) 24 M
26 F Claustrophobic subjects who failed a
previous MR examination
Genser-Medlitsch
& Schutz 2004 Prospective
observational 115 (55 therapy
clients, 60
nontherapeutic
persons)
NS NS Therapy clients and persons of a no
treatment waiting list participated
Huflejt-Lukasik Prospective
observational 19 Range age 21-46 y 12 F
7 M Subjects with difficulty in social interac-
tion, family, marital and relationship
problems, low self-esteem, depressive
symptoms, anxiety disorders, phobic
problems, efficiency and concentration.
Krugman
et al. 1985 Randomized
Controlled Trial 55 Data not shown 27 F
28 M Undergraduate students with anxiety in
public speaking situations
Liberman 1984 Prospective
observational 12 Data not shown Data not
shown Subjects diagnosed with Simple Phobia
(DSM III criteria)
Ojanen 2004 Prospective
observational 62 Range age
18-54 50 F
12M Subjects with work exhaustion, anxiety,
depression, low self-esteem, phobic
problems, insomnia
Pourmansour
1997 Randomized,
controlled, parallel-
group clinical trial
42 Range 18-47 21 F
21M Patients with fear of dental procedures
Reckert 1999 Randomized
Controlled Trial 50 Mean age
39.7 years 36M
14F 40 specific phobias, 10 social phobias
Rogers 1993 Randomized
Controlled Trial 38 Data not shown 38M Post Traumatic Stress Disorder
Stipancic
et al. 2010 RCT 106 20 to 61 years 22 M
78 F Psychotherapy clients
Witt 2003 Prospective
observational 73 Median age 41 years
(range 18-66 y) Data not
shown Subjects allergic to birch pollen
Study
(reference) NLP interventions Applied measures Results
Allen 1982 NLP Phobia Technique Behavior Avoidance Test
Fear Thermometer No significant effects of NLP treatment
on subject’s fear of snakes
Bigley
et al. 2010 Clare`s fast phobia cure.
One session of one hour Spielberger`s State Trait
Anxiety Inventory for assessing the
anxiety level.
30 subjects (76%) completed the MR
examination.
Nine subjects went on the scanner bed,
but were obtained unusable images, and
three didn`t consider going into the
scanner.
Genser-Medlitsch
& Schutz 2004 General individual
complaints, clinical
symptoms, coping strategies,
locus of control tendencies
3 sessions
Standardised psychological
questionnaire on individual
complaints, clinical symptoms, coping
strategies, locus of control tendencies
NLPt group registered significantly
improvements and lasting effects than the
control group
Huflejt-Lukasik Short-term NLP therapy
1 session/week, 5 months,
min. 1 month
SKNS (measures the level of self-
focused attention)
CISS ( measures the way one deals
with stress in some dimensions)
SCL-90 (diagnoses behaviors
(symptomatic dementia).
NLPt is effective method of receiving
positive changes. During therapy they
registered a decrease in public self-
consciousness, emotion-orientation in
dealing with stress, and in
psychopathological symptoms.
Krugman
et al. 1985 NLP phobia intervention&self
desensitization treatments
(kinaesthetic anchoring
Techniques, visualization)
Single session.
Personal Report of
Confidence as a Speaker Scale.
Paul`s Modified
Behaviour Checklist
Overall, the findings of this study indicate
that the NLP single-session treatment for
phobias was no more effective in reducing
public speaking anxiety than a self-control
desensitization intervention of equal dura-
tion or a waiting-list control condition.
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
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Table 2. Continues
Study
(reference) NLP interventions Applied measures Results
Liberman 1984 Visualisation, anchoring.
Two sessions, each lasting
less than an hour.
Fear Thermometer, Symptom
Checklist 90 (SCL-90R) Fear Survey
Schedule (FSS III)
NLP treatments was effective in reducing
phobic behavior and in reducing fear,
discomfort and the intensity of a wide
range of symptoms.
Ojanen 2004 NS SWB( Subjective Well-Being) –
consisting 7 DVAS ( Descriptive
visual analogue scales)
TWB – Therapist Rated Well Being
PE – Total Problem Experience
The ratings of the clients about the
therapy were very positive, they changed
into better. The therapeutic relationships
were highly positive.
Pourmansour
1997 One two-hour Collapse-
Anchors session State-Fear-Questionnaire Significant positive effect of NLP treat-
ment, reduction of fear of dental
procedures
Reckert 1999 NLP Phobia Techniques, 2
sessions Beck Anxiety Inventory (BAI)
State-Trait-Anxiety Inventory (STAI) For clients with light phobias no signi-
ficant effects were found; for client with
severe phobias there was a significant
effect on reduction of fear response
Rogers 1993 NLP Three Place Visual
Kinesthetic Dissociation,
3 sessions
Mississipi Scale for Combat Related
PTDS (MISS)
Sleep Self-Report Symptom Severity
Index (SSI)
Betts Questionnaire of Mental
Imagery (QMI)
Vividness of Imagery Scale
Combat Stress Index (CSI)
The addition of NLP sessions did not
significantly enhance the effects of the
PTSD program
Stipancic
et al. 2010 NLP therapy on a number of
psychology difficulties and
perceived quality of life
(QoL)
1 session*60 min/week
Average number of sessions =
20; (range 10-40 sessions)
Structured Interview for DSM IV
Personality Disorder
Croatian Scale of Quality of Life
(KVZ)
In the therapy group, there was a
significant decrease of clinical symptoms
and increase in QoL
Witt 2003 The Hildesheim Health
Training – for the mental
handling of allergies
8 meetings (2 per week).
2 hours – individual
conditioning, psychological
factors and believe system +
25 min. relaxation
The Skin Prick Test
Krampen-AT-
Symptomscale
Rehabilitation Psychological
Diagnostic System
NLPt has an effect on allergic sensitivity.
It was in strong combination with
Psychological Items, Aliments and
Medication.
Stipancic et al. 2010 examined in 106 subjects (22
males and 84 females) the short-term and long-term
effects of NLPt on a number of psychological diffi-
culties and perceived quality of life. Patients were set
to a therapy group (assessment prior to and immedia-
tely after therapy, and at a five-month follow-up
session) or to a control group (assessment at pre-test,
simultaneously by the treatment group and 3 months
later). One session of 60 minutes took place weekly,
and the number of sessions per subject differed from
each participant, according to the individual need of
each of them. The average number of sessions was 20
(range: 5-65, with 89% of participants in the range 10-
40) and the effectiveness of NLPt assessed during the
individual therapy sessions. To measure the clinical
symptoms are used the Structured Clinical Interview
for DSM-IV (SCID I) and Structured Clinical Inter-
view for DSM-IV Personality Disorders (SCID II). To
determine the quality of life the Croatian Scale of
Quality of Life (KVZ) was applied. Seven psycho-
therapists, with 10 to 20 years’ experience in NLPt,
participated in the study. The therapy group presented
a significant improvement in having fewer psycho-
logical difficulties and better-perceived quality of life,
than the control group.
The overall standardized mean difference was
d=0.51 with a confidence interval of CI=[0.20; 0.82].
Figure 2 displays the forest plot for the analysis. Effect
sizes for each study are available in Table 3. Sensitivity
analysis showed no significant influence of omitting
every single study once. The point estimate varied
between d=0.42 and d=0.61.
In two articles, relevant data were neither described
in the paper nor could be determined via contacting the
authors. In these two cases, a conservative approach was
chosen, according to Lipsey and Wilson 2001. No
information about the effect could found in Allen
(1982). Therefore, the effect size was fixed at d=0.
Bigley (2010) reported significant results but gave no
further numerical information.
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363
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Figure 1. Flow chart for process of screening electronic databases and inclusion of trials in the study
Figure 2. The overall effect of NLP intervention (standardized mean difference with a confidence interval)
Table 3. Risk of bias quality assessment
Study characteristics Quality coding
Therapist=
author Therapist=
NLP professional Sample=
only students Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q
percent
Allen 1982 n.a. n.a. yes 1 1 0 1 1 0 1 1 0 1 70
Bigley et al. 2010 Yes partly no 1 0 0 n.a. 1 0 1 1 0 n.a. 50
Genser-Medlitsch
& Schütz 2004 No Partly no 0 1 0 0 1 1 0 1 0 1 50
Huflejt-£ukasik (n.a.) Yes Yes no 0 1 0 1 0 1 0 1 0 1 50
Krugman et al. 1985 n.a. Partly yes 0 1 0 1 0 0 1 1 1 1 60
Liberman 1984 Yes n.a. no 1 1 0 1 1 0 1 1 0 0 60
Ojanen 2004 No Yes no 0 1 1 n.a. 1 1 0 1 0 n.a. 62.5
Pourmansour 1997 Yes n.a. no 0 1 0 1 1 0 1 1 0 1 60
Reckert 1999 Yes Yes no 1 1 0 1 0 1 1 1 0 1 70
Rogers 1993 yes No no 1 1 0 1 1 1 1 1 0 1 80
Stipancic et al. 2010 n.a. Yes no 0 1 0 1 0 1 1 1 0 1 60
Witt 2003 n.a. n.a. no 1 0 0 0 1 1 1 1 1 1 70
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363
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Across the twelve studies, only in four studies the
therapist was a professional practitioner (Huflejt-
£ukasik, Reckert 1993, Ojanen et al 2004, Stipancic et
al. 2010). In other two studies, the participants were
students (Allen 1982, Krugman et al. 1985). Main
problems reported by subjects were anxiety and
phobias. Of the twelve studies selected, in five studies
the outcome was fear and in four studies the outcome
was psychological symptoms. Two studies are assessing
the quality of life and one study the allergy symptoms.
Most of the studies were based on a prospective design.
Therefore the smallest effect size possible consi-
dering the given sample size and an assumed signi-
ficance level of á=0.05 was chosen for analysis. Since
this method is very conservative, it can cause a down-
ward bias in the final mean effect size.
Risk of bias
Ten of the total number of studies (12) used correct
method of selection of persons (Q2). In nine studies,
intervention was described sufficiently (Q7). In seven
studies, the follow-up period was long enough for
outcomes to occur (Q6). In all twelve studies, criteria
for measuring outcomes was clearly defined (Q8) (see
Table 2).
Publication bias
The visual inspection of the funnel plot as depicted
in Figure 2 showed no asymmetry. Rosenthal’s Fail-safe
N indicated that 174 studies with a null effect would be
needed to reach non-significance of the current analysis.
Orwin's Fail-safe N showed that 30 studies with an
effect of d=0.1 would be necessary to reduce the overall
impact to a trivial d=0.2. Neither Begg and Majumdar's
rank correlation nor Egger’s regression test was
significant (p=0.73 and p=0.45, respectively), which
indicates no publication bias. Trim-and-fill analysis
(Duval & Tweedie 2000) showed no effects to be
missing.
DISCUSSION
Summary of main results
The effects of NLP interventions were compared in
12 trials involving 658. Of the twelve studies selected,
only one study had a large number of participants
(N=115 psychotherapy clients). In that randomly
controlled trial, the NLP therapy group showed a
significant improvement and longer lasting effects of
psychotherapy than the control group (Genser-
Medlitsch & Schutz 2004).
An experimental study showed that NLPt influenced
the allergic immune function in birch pollen allergic
humans and the participants experienced significant
improvement in all psychological symptoms (Witt
2003). In another study with a small sample size (12
participants) diagnosed with Simple Phobia, with a pre-
test and post-test control group design. NLP treatment
seemed to be effective in reducing phobic behaviour,
fear, and discomfort (Liberman). In one study, Krugman
et al. 1985 indicated that a single session of NLP was
not effective in reducing anxiety in public speaking
situations.
Summary consideration of research quality
Overall, the quality of the studies was judged as
good enough. The most common reasons for occasional
inferior quality were the small number of participants
and the publication vintage on some studies. Also, in
one study no information about the effect could be
found and in another one, significant results were
reported but no further numerical information was
available.
Strengths and limitation of this study
That study represents the first meta-analysis eva-
luating the effectiveness of NLP therapy for individuals
with social/psychological problems. Another advantage
of this review includes the searching of conference
proceedings. Also the inclusion of unpublished data to
provide a comprehensive analysis of all available
evidence. A plus is the rigorous assessment of proof
quality which has been incorporated into review con-
clusions using standard methods. Potential limitations
in primary observational studies contributing to this
study, however, limit confidence in the conclusions
that might draw from the available evidence for NLP
modalities.
Implications for further research
Although many studies are aimed to determine the
efficacy of NLPt, there is a major lack of high-quality
data from observational, experimental studies or
randomized trials on this field. Up until now there is
insufficient data to recommend this form of therapy
strongly in reducing some psychosocial problems.
CONCLUSION
Our meta-analysis review found evidence to support
the positive effects of this form of psychotherapy.
However, further investigations are needed to confirm
the effectiveness of Neuro-Linguistic Therapy on
individual’s outcomes since most of the evidence is
available from smaller observational studies only.
Acknowledgements: None.
Conflict of interest: None to declare.
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363
362
References
1. Allen KL: An investigation of the effectiveness of neuro-
linguistic programming procedures in treating snake pho-
bics. Ph.D. Doctoral Dissertation, University of Missouri -
Kansas City, United States – Missouri, 1982. Retrieved
from http://proquest.umi.com/pqdweb?did=752856851
&Fmt= 7&clientId=36147&RQT=309&VName=PQD.
2. Bigley J, Griffiths PD, Prydderch A, Romanowski CA, Miles
L, Lidiard H & Hoggard N: Neuro linguistic program-
ming used to reduce the need for anaesthesia in claustro-
phobic patients undergoing MRI. [Evaluation Studies].
The British journal of radiology 2010; 83:113-117. doi:
10.1259/bjr/14421796.
3. Cowley DE: Prostheses for primary total hip replacement.
A critical appraisal of the literature. Int J Technol Assess
Health Care 1995; 11:770-778.
4. Deeks JJ, Dinnes J, D'Amico R, Sowden AJ, Sakarovitch
C, Song F, Altman DG: Evaluating non-randomised
intervention studies. Health Technol Assess 2003; 7:iii-x,
1-173. doi: 96-26-99 [pii]
5. Dryden W & Golden WL: Cognitive-behavioural appr-
oaches to psychotherapy (pp. XII, 392). London: Harper
& Row, 1986.
6. Duval S & Tweedie R: Trim and fill: A simple funnel-plot-
based method of testing and adjusting for publication bias
in meta-analysis. Biometrics 2000; 56:455-463.
7. Einspruch E: Neurolinguistic Programming in the
treatment of phobias. Psychotherapy in Private practice
1988; 6:91-100.
8. Ellis A & Grieger RM: Handbook of rational-emotive
therapy. New York: Springer, 1977.
9. Ferguson DM: The effect of two audiotaped neuro lin-
guistic programming phobia treatments on public spea-
king anxiety. Ph.D. 8810355, The University of Tennessee,
United States – Tennessee, 1987. Retrieved from
http://proquest.umi.com/pqdweb?did=753377451
&Fmt=7&clientId=36147&RQT=309&VName=PQD.
10. Genser-Medlitsch M & Schütz P: Does neurolinguistic
psychotherapie has effects. Nowiny Psychologiczne 2004;
1:23-48.
11. Genser-Medlitsch M: Neurolinguistisches Programmieren
in der therapeutischen Praxis. master thesis, University of
Vienna, Vienna, 1997.
12. Grawe K, Donati R & Bernauer F: Psychotherapie im
Wandel. Von der Konfession zur Profession. Göttingen:
Hogrefe, 1994.
13. Gray RM: The Brooklyn Program: Innovative Approaches
to Substance Abuse Treatment. Federal Probation
Quarterly 2002; 66:9-16.
14. Grinder J & Bandler R: Frogs into Princes: Neuro
Linguistic Programming, 1979. Moab, UT: Real People
Press. ISBN 0-911226-19-2.
15. Hayes SC & Strosahl KD: A practical guide to acceptance
and commitment therapy (pp. XVI, 395). New York, NY:
Springer, 2004.
16. Heckrath C & Dohmen P: Zu der empirischen Basis der
'hochsignifikanten Überlegenheit’ der kognitiv-behavio-
ralen gegenüber den psychoanalytischen Therapie-
verfahren. Zeitschrift für psychosomatische Medizin und
Psychoanalyse 1997; 43:179-201.
17. Hedges LV & Vevea JL: Fixed- and random-effects models
in meta-analysis. Psychological Methods 1998; 3:486-504.
18. Huflejt £ukasik M & Regulska H: The effectiveness of
Neuro-Linguistic Psychotherapy: the results of the study
in Poland. NLPt & the medical model: working across
environments. NLPtCA & EANLPt conference at Regent’s
College, London, 2005.
19. Huflejt-£ukasik M: The Effectiveness of Neuro-Linguistic
Psychotherapy. Warsaw University. Warsaw. Internal
paper (n.a.).
20. Konefal J & Duncan RC: Social anxiety and training in
neuro-linguistic programming. Psychological reports
1998; 83:1115-1122.
21. Konefal J, Duncan RC & Reese MA: Neuro linguistic
programming training, trait anxiety, and locus of control.
Psychological Reports 1992; 70:819-832.
22. Krugman M, Kirsch I, Wickless C, Milling L, Golicz H &
Toth A: Neurolinguistic Programming Treatment for
Anxiety: Magic or Myth? Journal of Consulting and
Clinical Psychology 1985; 53:526-530.
23. Liberman MB: The treatment of simple phobias with
neuro-linguistic programming techniques. Ph.D. Doctoral
Dissertation, Saint Louis University, United States –
Missouri, 1984. Retrieved from http://proquest.umi.com/
pqdweb?did=753612441&Fmt=7&clientId=36147&RQT
=309&VName=PQD
24. Lipsey MW & Wilson DB: Practical Meta-Analysis.
Thousand Oaks, CA: SAGE Publications Inc, 2001.
25. Muss DC: A new technique for treating post-traumatic
stress disorder. The British journal of clinical psychology
/ the British Psychological Society 1991; 30:91-92.
26. Ojanen M, Kotakorpi S, Kumpula S, Tankklu M, Vadén T.,
Vikeväinen-Tervonen L, Hiltunen S: Terapiastako ratkaisu
– NLP-perustaisen psykoterapian tuloksellisuudesta
(Solution form therapy – results of NLP-based
psychotherapy). Helsinki: Mielikirjat, 2004.
27. Pourmansour J: NLP und Zahnarztangst? - Eine Studie
zur Effektivität der NLP-Intervention. Master's thesis,
University of Münster, Münster, 1997.
28. Reckert H-W: Die NLP-Phobiebehandlungstechniken in
der Behandlung von spezifischen und sozialen Phobien -
eine Therapievergleichsstudie mit der systematischen
Desensibilisierung in sensu. Doctoral dissertation, Uni-
versity of Tübingen, Tübingen, 1999.
29. Reckert H-W: NLP-Anker-Kollabieren als Kurzzeitthe-
rapie von Studierenden mit Prüfungsangst eine Therapie-
vergleichsstudie mit mentalem Training. Master's thesis,
University of Tübingen, Tübingen, 1993.
30. Riess Gabriele, Joachim Hagleitner, Waltraud Bednar
Gesundheit Österreich, Wirksamkeitsnachweise f Psycho-
therapie, 2009.
31. Schütz P, Schneider-Sommer S: Theorie und Praxis der
Neuro-Linguistischen Psychotherapie Taschenbuch,
Jungermann, 2001.
32. Simpson Symon DR, Dridy W: Comparison between REBT
and Visual/Kinaesthetic Dissociation in the Treatment of
Panic Disorder: An Empirical Study J Rat-Emo Cognitive-
Behav Ther 2011; 29:158–176.
33. Smith M, Glass G & Miller T: The Benefits of Psychothe-
rapy. Baltimore, MD: John Hopkins University Press, 1980.
34. Stenographisches Protokoll, 146. Sitzung des Nationa-
lrates der Republik Österreich, 07. Juni 1990, p 16892,
Abgeordneter Smolle.
35. Stipancic M, Renner W, Schütz P & Dond R: Effects of
Neuro-Linguistic Psychotherapy on psychological difficu-
Cătălin Zaharia, Melita Reiner & Peter Schütz: EVIDENCE-BASED NEURO LINGUISTIC PSYCHOTHERAPY: A META-ANALYSIS
Psychiatria Danubina, 2015; Vol. 27, No. 4, pp 355–363
363
lties and perceived quality of life. Counselling and
Psychotherapy Research 2010; 10:39-49.
36. Wake L, Gray R., Bourke F: The Clinical Effectiveness of
Neurolinguistic Programming, Routledge Mental Health,
2012.
37. Wells G & Shay B: Data extraction for nonrandomised
systematic reviews. University of Ottawa. Ottawa.
38. Witkowski T: Thirty-five years of Research on Neuro-
Linguistic Programming. Polish Psychological Bulletin,
2009; vol 40.
39. Witt K: Neuro-Linguistic -Psychotherapy (NLPt) trea-
tment can modulate the reaction in pollen allergic humans
and their state of health. International Journal of Psych-
otherapy 2008; 12:50-60.
Correspondence:
Dr. Cătălin Zaharia
Mind Master Association
Bucharest, România
E-mail: catalin@nlpt.ro
