ENACT: The efficacy and mechanisms of action of N-acetylcysteine as an adjunct treatment for first episode psychosis.


Dataset description

Dataset derived from a 52-week randomized, double-blind, placebo-controlled trial investigating the efficacy of N-acetyl cysteine (NAC) as an adjunctive treatment for young individuals experiencing first episode psychosis (FEP). The study aims to determine if NAC, administered at 2000 mg daily in addition to treatment as usual (TAU), can reduce symptom severity and prevent the progression of early psychosis into a chronic disorder. The trial involves 162 participants aged 15-25 years, recruited from the Early Psychosis Prevention and Intervention Centre, who are randomized to receive either NAC or placebo for 26 weeks, followed by a 26-week non-treatment follow-up period.
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FOR: Mental Health |

Source Study




Phase 3 / Phase 4


Government body,National Health and Medical Research Council

Scientific enquiries

Prof Sue Cotton

Brief Summary

First episode psychosis (FEP) may lead to devastating, chronic illness. For many individuals with FEP, a progressive worsening of symptoms, decline in cognition, and associated reduction in quality of life is often observed. There is evidence to suggest that this illness progression can be diminished, and perhaps even averted, if appropriate treatments are given at the early stages of illness. N-acetyl cysteine (NAC) is a supplement form of an amino acid antioxidant found naturally in foods such ....
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Key Inclusion Criteria

i. Aged 15 to 25 years at time of study enrolment; ii. Treatment stability: at least two weeks of stability in the use of primary medication (e.g., anti-psychotic medications) iii. Within their first three months of admission to the Early Psychosis Prevention and Intervention Centre (EPPIC); and iv. Capacity to consent to the study and comply with study procedures.

Key Exclusion Criteria

i. Previous episode of psychosis or previously been treated with an anti-psychotic prior to entry to the program; ii. Known or suspected clinically relevant systemic medical disorder; iii. Females who are pregnant or lactating; iv. Prior sensitivity or allergy to NAC; v. Currently enrolled in another research study vi. Inability to comply with either the requirements of informed consent or the treatment protocol; and/or vii. Non-fluency in English

Can healthy volunteers participate?




Sample Size    162

Min. age    15 Years

Max. age    25 Years

Sex    Both males and females

Condition category    First episode psychosis

Condition code    Mental Health


Intervention code Treatment: Drugs

N-acetylcysteine 2000mg once daily (2 x oral capsules 1000mg each capsule) for 26 weeks. Medication adherence will be assessed using the Medication Adherence Rating Scale, and returned study medication will be counted and recorded.


Control group Placebo

The study is placebo-controlled. Placebo consists of 2000mg microcrystalline cellulose (2 x oral capsules 1000mg each capsule) for 26 weeks, with excipients matched to active treatment.


Outcome: Change from baseline in total score on the Positive and Negative Symptoms Scale (PANSS) total score for NAC versus placebo
Timepoint: 4-, 8-, 12-, 26- (primary time point) and 52-weeks post commencement of intervention

Study Protocol: Not Available
Data Dictionary: Not Available

Will individual participant data (IPD) for this trial be available?


What data in particular will be shared?

All of the individual participant data collected during the trial, after de-identification.

When will data be available?

Immediately following publication and for a further 3 years.

Available to whom?

Investigators whose proposed use of the data has been approved by an independent review committee.

Available for what types of analyses?

To achieve aims outlined in the approved protocol

Source study information is derived from the Australian New Zealand Clinical Trials Registry (ANZCTR). For more information on the ANZCTR, please see