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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Randomised control trial of monoamine precursors for the treatment of psychostimulant withdrawal
Scientific title
A double-blind, randomised, placebo controlled trial of monoamine precursors in the treatment of psychostimulant withdrawal in adult humans seeking treatment for psychostimulant use
Universal Trial Number (UTN)
Trial acronym
Monoamine precursor trial
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Psychostimulant withdrawal 1592 0
Condition category
Condition code
Mental Health 1695 1695 0 0

Study type
Description of intervention(s) / exposure
Oral monoamine precursors (5-HTP (300mg daily), L-tyrosine (1500mg daily), dl-phenylalanine (2000mg daily)) and oral multivitamins (3 tablets daily, one multivitamin tablet is on average in the range of 1200mg – 1400mg). All participants will be offered 4 weekly sessions of outpatient cognitive behavioural therapy (CBT) of approximately one hour duration each.
Intervention code [1] 1575 0
Treatment: Drugs
Comparator / control treatment
Oral placebo and oral multivitamins (3 tablets daily), daily for 4 weeks. Placebos contain non-therapeutic excipients and are matched for colour and size. All participants will be offered 4 weekly sessions of outpatient cognitive behavioural therapy (CBT) of approximately one hour duration each.
Control group

Primary outcome [1] 2347 0
Psychostimulant withdrawal.
Timepoint [1] 2347 0
Self-report assessed daily for one month with the Amphetamine Cessation Symptom Assessment (ACSA).
Secondary outcome [1] 4090 0
1. Number of outpatient CBT sessions attended
Timepoint [1] 4090 0
assessed at the completion of the intervention
Secondary outcome [2] 4091 0
2. Abstinence rates, assessed using the Timeline Followback Method.
Timepoint [2] 4091 0
during treatment

Key inclusion criteria
Inclusion Criteria 1. DSM-IV Classification of Amphetamine or Cocaine Dependence / Severity of Dependence Scale (SDS) score greater than 4. 2. Psychostimulant use at least 2 times per week with at least 3 month history.
Minimum age
18 Years
Maximum age
55 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Exclusion Criteria 1.Alcohol dependence (AUDIT) 2. Use of drugs other than psychostimulants 4 times a week or more (nicotine dependence is permitted)3. Amino acid contraindications (eg., phenylketonuria) 4. Malabsorption medical conditions (eg., Crohn’s disease, ulcerative colitis) 5. Currently prescribed antidepressant / mood stabilising / antipsychotic medications 6. Current suicidal ideation 7. History of schizophrenia / other psychotic illness 8. Hospitalisation in the past 12 months for more than 24 hours for psychiatric symptoms including hallucinations, delusions and suicidal ideation 9. Elevated Liver Function Tests (3 times higher than normal levels) 10. Currently pregnant or likely to become pregnant in the following month.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation involves contacting the holder of the allocation schedule who is at central administration
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computerised sequence generation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Study is double-blind. Study participants, assessing counsellor, counsellor delivering CBT intervention, and all other project staff excluding staff member responsible for randomisation will be blinded to the study condition of participants.
Phase 3
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 1835 0
Government body
Name [1] 1835 0
NSW Department of Health
Address [1] 1835 0
73 Miller St, North Sydney, 2060
Country [1] 1835 0
Primary sponsor type
Sydney South West Area Health Service
Drug Health Services, Royal Prince Alfred Hospital, Missenden Rd Camperdown NSW 2050
Secondary sponsor category [1] 1656 0
Name [1] 1656 0
Address [1] 1656 0
Country [1] 1656 0

Ethics approval
Ethics application status
Ethics committee name [1] 3435 0
Sydney South West Area Health Service
Ethics committee address [1] 3435 0
Ethics committee country [1] 3435 0
Date submitted for ethics approval [1] 3435 0
Approval date [1] 3435 0
Ethics approval number [1] 3435 0

Brief summary
The study aims to: identify the safety and acceptability of monoamine precursor provision in the management of psychostimulant withdrawal; explore the impact of monoamine precursor provision on engagement and retention in treatment; research the effect of monoamine precursor provision on the clinical course and severity of psychostimulant withdrawal; and, explore the impact of monoamine precursor provision in improving abstinence rates.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 27509 0
Address 27509 0
Country 27509 0
Phone 27509 0
Fax 27509 0
Email 27509 0
Contact person for public queries
Name 10764 0
Toby Lea
Address 10764 0
Drug Health Services
Locked Bag 4002
Ashfield NSW 2131
Country 10764 0
Phone 10764 0
+61 2 93781314
Fax 10764 0
+61 2 93781338
Email 10764 0
Contact person for scientific queries
Name 1692 0
Dr Adam Winstock
Address 1692 0
Drug Health Services
Locked Bag 4002
Ashfield NSW 2131
Country 1692 0
Phone 1692 0
+61 2 93781316
Fax 1692 0
+61 2 93781338
Email 1692 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary