<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hi, I have a unstable mood that I could be sometimes waking up sad with no reason, an extreme mood swing, and I don t wish to interact with anyone else sometimes. I gain fat very fast these few years and I don t have the urge of having sex. Is that a depression symptoms or hormones problem? I m still 26. Thank you.  <response>: We understand your concerns went through your details. Mood swings can occur as a symptom of psychiatric disorders, such as bipolar disorder or borderline personality disorder, or they may result from a medical condition that directly affects the central nervous system, such as dementia, brain tumors, meningitis, and stroke. I suggest you should consult a psychologist psychiatrist for detailed evaluation. If you require more of my help in this aspect, please use this URL. Make sure that you include every minute details possible. Hope this answers your query. Available for further clarifications. Good luck. 