Related party transactions (Details) - USD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Related party transactions
Salaries and bonuses	$ 1,921,684	$ 2,416,964	$ 1,973,250
Share-based compensation	60,476	310,806	192,160
Performance share units	(53,100)	97,853
Total	1,929,060	2,825,623	$ 2,165,410
Transactions with significant shareholder - Greybrook Health Inc
Trade and other payable for management services	$ 0	$ 0

This element represents for key management personnel compensation share performance units.

No definition available.

Name:	gbnh_KeyManagementPersonnelCompensationPerformanceShareUnits
Namespace Prefix:	gbnh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amounts payable resulting from related party transactions. [Refer: Related parties [member]]

+ References

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-Number 24
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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of compensation to key management personnel. [Refer: Key management personnel of entity or parent [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2021-01-01
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+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of compensation to key management personnel in the form of share-based payments. [Refer: Key management personnel of entity or parent [member]]

+ References

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-Name IAS
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-URIDate 2021-03-24

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of compensation to key management personnel in the form of short-term employee benefits. [Refer: Key management personnel of entity or parent [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2021-01-01
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration