I am no expert but I have a little book that recommends the following:
Anxiety: 4 drops cypress, 3 drops sandalwood, 3 drops patchouli
Apathy: 4 drops tea tree, 3 drops rosemary, 3 drops lemon
Agitation: 4 drops lavender, 4 drops palmarosa, 1 drop myrrh
Nervousness: 4 drops lavender, 3 drops bergamot, 3 drops neroli