Giving misleading information or omitting or concealing information during the recruitment and vetting process is viewed very seriously and would be seen as evidence of untrustworthiness.
In such circumstances, your vetting clearance may well be refused, even though what you were seeking to conceal may not in itself have caused a problem.
The vetting process involves completing detailed questionnaires, discussing these with a Vetting Officer and agreeing references for interview.
It is important that you provide full and accurate information as any omissions can cause a delay to your application.
Candidates undergoing security vetting are treated impartially and consistently irrespective of any disability they may have, or of their gender, marital status, age, ethnicity, religious affiliation or sexual orientation.
GCHQ is an inclusive organisation and values having a neuro-diverse workforce and the vetting process reflects this.
You should not post on social media sites about your application or discuss it with anyone else at this stage.