Thought I would share my experience in case others have the same problem since it helped in my case. TL DR: strange behavior and bad attitude / disagreeableness were 90% caused by low serotonin levels, and I was able to greatly improve them.
Short background: I had to step up as caregiver for my mom late last year since she could no longer be counted on to take care of herself (ate poorly - not enough good food - craved junk food but still underweight). In trying to help her I noticed some behaviors from her that she had never shown before.
Any time I tried to get her to do something there would be an argument. If I told her she needed to do something or I offered a new idea she would disagree before three words left my mouth. She started to horde things (in her bedroom, her chair in the living room, the kitchen table). She'd get easily distracted while eating - if she saw a plastic bag on the kitchen table she'd pick it up and start futzing with it. It was so bad I had to clear everything off the table and hide things just to get her to eat.
Then the bizarre behavior - weird bathroom habits / obsessions, walking around without pants / underwear. Insisting that our Senator was on the radio late at night giving recommendations on what to eat (it was a late night talk show host reading commercials). Couldn't be convinced of anything that went against what she thought was true.
She went on and on about old things that upset her - when I would address one she'd move on to another thing, then another, and then circle back to the first item in a never ending loop.
She has Alzheimer's but this was a rapid progression from where she was just months before. She mentioned not sleeping so I started researching natural substances to help her sleep. Along the way I saw someone mention low serotonin levels causing problems like she was having. I found a video that listed these symptoms: (don't know if I can post links, but the video is here: https://www.youtube.com/watch?v=3_IiJmIL9ss&t=516s)
- Frequent feeling of sadness
- Constant worrying
- Upset when things don't go your way (rigid/inflexible)
- Upset when things are out of place
- Tend to be oppositional or argumentative
- Repetitive negative thoughts
- You don't like change
- Tend to hold grudges
- Trouble shifting attention from subject to subject
- Trouble shifting behavior from task to task
- Difficulty seeing options
- Tendency to hold on their own opinion and not listening to others
- Tendency to be locked in a course of action
- Needing to have things done in a certain way
- Others complain that you worry too much
- Tend to say "no" without thinking
- Tend to predict fear
She had every one of them.
I found people suggesting Saint John's Wort to help with low serotonin levels. I found a bottle of liquid SJW drops without a bunch of chemicals and ordered it. Those two days waiting for amazon to deliver took forever. While waiting I cleared it with her doctor to make sure it wouldn't affect her regular medication.
I started with one drop in a glass of water. No side effects, so I went to 2. Soon It was up to 3 drops in the morning and 2 at night. Along the way all the bad behavior started to slowly improve. She stopped arguing about every little thing. She didn't mind when my sister or I cleaned up the clutter that she didn't want to get rid of just weeks ago. Her actions were more rational, her obsessions were greatly reduced. She could eat without without getting distracted by everything (but she still eats too slow - can't change 80 year old habits).
Her poor sleep habits still cause problems but as long as I keep the SJW flowing all the symptoms she had are greatly reduced.
If you have a LO with similar problems, check out serotonin levels. Diet changes can help, SJW worked for my mom but make sure to check with their doctor first - SJW can interfere with meds (like heart medications) so you definitely don't want to start it without getting approval.