Every Christian needs discernment to tell Satan's accusations from the conviction of the Holy Spirit. Both can produce feelings of guilt and unworthiness, yet they differ radically in origin, purpose, character and outcome, and confusing the two leads either to crushing despair or to a seared conscience.
Guilt is not first a medical condition. It is a spiritual reality that concerns our standing before God: a person who has broken His law is objectively guilty whether they feel it or not. No therapist can absolve that guilt, and telling yourself to forgive yourself is make-believe. Only God, who declares us guilty, can set us free from it, and He has done so through the atoning work of His Son.
Satan, the accuser of the brothers and the father of lies, uses temptation to draw believers away and accusation to torment them, aiming to make them stop praying and doubt their salvation. The Spirit convicts in order to lead us to repentance, which is God's gift, and to Christ. The final word belongs to Romans 8: if God is for us, who can be against us, and who shall bring any charge against God's elect?