How long does a PHD in Psychology take?

G

I have a former colleague who has a BA in Social Sciences (Major Politics) from the 1990s and is adamant that she did a PHD in Behaviour Psychology from Open Univ in 2005-2006. Surely this is wrong? I really don't want to believe she is lying but......
Can you have a degree in Social Sciences and then do PHD Psychology?
This former colleague has now landed a prestigious post based on this qualification. What do you guys think?

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