SSRI medication stabilizes the serotonin level in the brain. It can have an excellent effect on many different psychical problems, and I have seen how severely jealous people have got well as if by magic. I recommend that you contact a medical doctor and try it out yourself. Carefully follow the doctor's instruction. Sometimes, the doctor may want to increase the dosage, if a low dose does not help. There are also other medicines, which sometimes help with severy jealousy problems. Best understanding of the right way to use medicines for jealousy may be given by a psychiatrist. Note that the effect of SSRI drugs can appear first after 2-3 weeks.
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Gestalt therapy
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helps you get into contact with your feelings in order to heal them, and cognitive therapy
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teaches you to think more sensibly and realistically so that you do not harm yourself by thinking in illogical or selfdestructive ways.