I found very little literature on this subject. The only thing that popped up was a US patent:
Patent US2008/0039526 : Composition for promoting sleep
The herbs are not restricted in particular, and anise, carrot seed, clove, coriander, cypress, cinnamon, juniper, ginger, sweet orange, pine needles, basil, patchouli, bitter orange, fennel, black pepper, bay, peppermint, bergamot, mandarin, myrrh, lemon grass, rosemary, grapefruit, vanilla, hyssop, eucalyptus, lime, lemon, ylang-ylang, cardamom, clary sage, jasmine, geranium, Bulgarian rose, rose, olibanum, chamomile, geranium, sandalwood, neroli, verbena, petitgrain, vetiver, majorum, melissa, rosewood, etc., can be cited as examples. Among these, peppermint is preferable.
This patent obviously describe a compound of products that can be used to promote sleep. Note that the word promote itself give a good clue to answer your question. Moreover, the inventors say that amount a considerable list, peppermint is preferable.
In conclusion, I cannot draw the conclusion that anise cannot treat effectively the insomnia. However, from the lack of valid source and the patent I found allow me to say that it is probably not highly effective.