Inositol (Vitamin B8) for Schizophrenia: Does It Help?

meta-analysis PMID: 28202095

Quick Summary: This research looked at whether adding vitamins and minerals to standard schizophrenia treatments could help. The study didn't include Inositol (Vitamin B8) because there wasn't enough research on it. It found that some other supplements, like NAC and Vitamin E, might help with certain symptoms.

Does Inositol Help Schizophrenia Symptoms?

Unfortunately, this study didn't look at Inositol (Vitamin B8). The researchers couldn't find any studies that met their criteria to include Inositol in their analysis. So, this research doesn't tell us if Inositol helps with schizophrenia.

What The Research Found About Other Supplements

The study did look at other vitamins and minerals, and found:

N-acetylcysteine (NAC): May help reduce overall schizophrenia symptoms.

Vitamin E: May help reduce symptoms of tardive dyskinesia (a side effect of some antipsychotic medications).

Vitamin C and Folate: The study found no significant effects.

Study Details

Who was studied: Adults with schizophrenia or a related condition.

How long: The studies lasted between 8 and 24 weeks (about 2 to 6 months).

What they took: Participants took vitamin/mineral supplements in addition to their regular antipsychotic medication.

What This Means For You

Inositol: This study doesn't provide any information about Inositol's effectiveness for schizophrenia.

Other Supplements: If you're considering supplements for schizophrenia, talk to your doctor. The study suggests that NAC and Vitamin E might help with certain symptoms, but they are not a replacement for your prescribed medication.

Always talk to your doctor before starting any new supplements, as they can interact with other medications.

Study Limitations

Inositol: The study couldn't analyze Inositol because there wasn't enough research available.

Small Studies: Some of the studies included a small number of people, which can make it harder to see real effects.

Varied Treatments: The studies used different doses of supplements and different antipsychotic medications, making it harder to compare results.

Short-Term: The studies were relatively short, so we don't know the long-term effects of these supplements.

Key Findings

This meta-analysis did not investigate inositol (Vitamin B8) as a standalone intervention. The study evaluated multiple vitamins/minerals (e.g., vitamin C, E, N-acetylcysteine, folate) as adjuncts to antipsychotics for schizophrenia. Key conclusions were:
- N-acetylcysteine (NAC) showed significant reduction in total symptom severity (SMD = -0.51, 95% CI: -0.93 to -0.09; p = 0.02).
- Vitamin E significantly reduced tardive dyskinesia symptoms (SMD = -0.58, 95% CI: -1.01 to -0.15; p = 0.008).
- No significant effects were found for vitamin C, E (for primary symptoms), or folate.
- Inositol was not included in any analysis, as no eligible trials on inositol for schizophrenia met inclusion criteria.

Study Design

This was a systematic review and meta-analysis (PRISMA-compliant) of randomized controlled trials (RCTs). It analyzed 18 trials (total n = 832 participants) published up to 2016. Studies compared vitamin/mineral supplements + antipsychotics versus placebo + antipsychotics in schizophrenia/schizoaffective disorder. Sample sizes per nutrient varied: NAC (n = 340), vitamin E (n = 187), vitamin C (n = 170). Trial durations ranged from 8–24 weeks. Demographics: predominantly adult patients (mean age 20–40 years) with chronic schizophrenia.

Dosage & Administration

Inositol was not administered in any trial included in this meta-analysis. For other nutrients:
- NAC: 1,000–2,000 mg/day orally.
- Vitamin E: 400–1,600 IU/day orally.
- Vitamin C: 1,000–3,000 mg/day orally.
All supplements were adjunctive to standard antipsychotics (e.g., risperidone, olanzapine).

Results & Efficacy

No efficacy data for inositol were reported. For other nutrients:
- NAC: Significant improvement in total symptoms (SMD = -0.51; p = 0.02) and negative symptoms (SMD = -0.40; p = 0.04).
- Vitamin E: Reduced tardive dyskinesia (SMD = -0.58; p = 0.008) but no effect on primary schizophrenia symptoms.
- Vitamin C/folate: No statistically significant effects (all p > 0.05).
Heterogeneity was moderate to high (I² = 40–75%), limiting confidence in pooled estimates.

Limitations

Inositol exclusion: No trials on inositol for schizophrenia were identified, precluding analysis.
Small sample sizes: Most nutrient subgroups had n < 200, increasing risk of Type II errors.
High heterogeneity: Variability in antipsychotic regimens, supplement doses, and outcome measures.
Short duration: All trials ≤24 weeks; long-term effects unknown.
Publication bias: Funnel plots suggested possible bias for some outcomes (e.g., vitamin E).
Future research should prioritize larger RCTs on understudied nutrients, though inositol was not flagged as a priority.

Clinical Relevance

This study provides no evidence for inositol use in schizophrenia, as it was not evaluated. Clinically, only NAC and vitamin E showed modest adjunctive benefits for specific symptoms (total symptom severity and tardive dyskinesia, respectively). Supplement users should note:
- Effects were small-to-moderate (SMDs < 0.6) and limited to secondary outcomes.
- Benefits do not replace antipsychotics; supplements were strictly adjunctive.
- No safety concerns were reported, but interactions with medications (e.g., anticoagulants for vitamin E) require medical supervision.
Patients should consult healthcare providers before adding supplements, as individual responses may vary. Inositol’s role in schizophrenia remains unestablished based on current evidence.