Abstract: 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/research) 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.