Watch his diet, try to stay away from too much white flour and white sugar, If he likes trail mix or mixed nuts, the essential fatty acids are great for helping your mood. Not sleeping soundly will cause moodiness too. I will also pray if their is something he is axnious about, that he will find away to tell you. Then it can be addressed through prayer. (My son acts out in anger when something is bugging him.)
I hope this helps, God Bless
CONCLUSIONS: Deficits in omega-3 fatty acids have been identified as a contributing factor to mood disorders and offer a potential rational treatment approach. This review identifies a number of hypotheses and studies for consideration. In particular, the authors argue for studies clarifying the efficacy of omega-3 supplementation for unipolar and bipolar depressive disorders, both as individual and augmentation treatment strategies, and for studies pursuing which omega-3 fatty acid, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), is likely to provide the greatest benefit.
If it can help Bipolar disorder, just think of what it could do for your son. It may take a few days to start noticing a change in mood.