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An Exploratory Open Label Study of Adjunctive L-lysine Treatment in Patients With Schizophrenia

An Exploratory Open Label Study of Adjunctive L-lysine Treatment in Patients With Schizophrenia

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00996242
Enrollment
10
Registered
2009-10-16
Start date
2007-09-30
Completion date
2009-03-31
Last updated
2009-10-16

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Schizophrenia

Keywords

Schizophrenia, L-lysine, PANSS

Brief summary

The objective of the present study was to investigate the possibility of using L-lysine, an amino acid that occurs naturally in food and which interferes with nitric oxide (NO) production, for the treatment of schizophrenia. L-lysine, 6 g/day, was administered to ten patients with schizophrenia as an add-on treatment to conventional antipsychotic treatment. The study was designed as a single-blinded, cross-over study where patients were randomly assigned to initial treatment with either L-lysine or placebo and screened at baseline, after four weeks when treatment was crossed over, and after eight weeks when treatment was terminated. The four-week L-lysine treatment regimen caused a significant increased in blood concentration of the amino acid and was tolerated well. The analysis of outcome measures showed a significant decrease in symptom severity as measured by the Positive and Negative Syndrome Scale (PANSS). Furthermore, the patient's ability to solve the Wisconsin Card Sorting Task (WCST) was significantly improved indicating increased problem solving capacity and cognitive flexibility. Subjective reports from three of the patients also indicated decreased symptom severity and enhanced cognitive functioning. In summary, these findings suggest potential beneficial effects of L-lysine treatment on symptom severity and cognitive deficits in patients with schizophrenia.

Interventions

6 g/day for four weeks

Sponsors

Stanley Medical Research Institute
CollaboratorOTHER
Göteborg University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)

Eligibility

Sex/Gender
ALL
Age
23 Years to 56 Years
Healthy volunteers
No

Inclusion criteria

* a stable phase of illness * a stable dose of antipsychotic medication * no other major medical conditions or other psychiatric diagnosis * normal admission laboratory tests and vital signs

Exclusion criteria

* substance abuse, apart from smoking

Design outcomes

Primary

MeasureTime frame
Psychotic symptoms severityEight weeks

Secondary

MeasureTime frame
Treatment safety assessmentEight weeks

Countries

Sweden

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026