Is my female colleague a manipulative 'pick me girl' or mentally unwell?

There is this female colleague who flirts with seniors of my office, especially those whom I befriend. She back-bites against her own team members to other teams and expects exclusive support from the trainer who is crazy about her. What is it with her? Is she simply - 'pick men girl or have some psychotic issues?
Is my female colleague a manipulative 'pick me girl' or mentally unwell?
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