Mercury in the 3rd does not guarantee that the information you gather will be correct. There may be inconsistencies between what you are told and what you intuitively feel. It will be your task to assess what is truth and what is fiction.
Mercury in the 3rd house of Solar return, can suggest that the rational thinking processes are stronger than feelings.
This is most likely to be so if the Moon is not particularly strong by house, sign, or aspect, and the chart is not watery.If the greater emphasis is on Mercury, decisions will be based on rational considerations rather than emotional needs. But if the Moon is very prominent in the chart, rational thoughts may be overwhelmed by emotional considerations.
When the interpretation for the Moon, (and/or Pluto), appears to conflict with the interpretation for Mercury, emotions and rational thoughts may seem to contradict one another. You may be torn between what you know or hear and what you feel in your heart or sense intuitively. If you are very stressed, unconscious needs may surface. Negative feelings, obsessions, compulsions, phobias, and extreme anger may defy rational control.
Your mental attitude during the year is very important.
You need to think clearly in order to function at an optimal level. Aspects to Mercury in the 3rd house can suggest influences that either hinder or promote logical thinking. Among the more detrimental influences are abusive substances such as alcohol and drugs. Mental illnesses, (especially depression and anxiety), are also negative influences which can affect one’s ability to think clearly.
These very negative manifestations correspond more closely to an individual’s negative behavioral pattern than to any one specific astrological pattern in the solar return chart. Although stress may be suggested by the solar return chart, disease is not. Those who are intimately and enthusiastically involved in life experience few problems. For them, great excitement rather than stress fuels their thinking processes.