Some info collected from various sources follows

Rambunctious and Hyperactive Cat Behavior

If your cat is attacking you, your furniture, phantom spirits and invisible mice; if he's bouncing off the walls and ceiling; knocking things off counter tops; stealing; carrying around or hiding the most unusual objects; don't worry, your cat is quite normal. Much of this obnoxious behavior is caused by his acting out play and predatory behavior. If these events occur in the middle of the night or in the wee hours of the morning, don't forget that cats are nocturnal animals. It's normal for their activity level to peak late at night or early in the morning.

This frequently happens with lonely, bored cats that have an excess of energy and no where for that energy to go. They cannot chase real mice and birds, or climb real trees, so they develop other habits to entertain themselves.

Many of these problems can be prevented or cured by providing games, exercise and entertainment for your kitty. Get on the floor and play with your cat. Don't just toss her a toy and expect her to play by herself. Tie a toy to the end of a string, toss it down the hall and reel it in, or slowly drag it across the floor. This gives kitty a moving target to chase and attack. Put a bird feeder outside a window so your cat can watch hummingbirds dive-bomb the fuchsia bush.

Sometimes kitten behavior, such as suckling and kneading, continues into adulthood. Provide your cat with something safe of his own towards which he can direct this behavior. If the cat decides to use you or your clothing for this activity, simply let him know you disapprove. A sudden, sharp shout or loud noise is usually sufficient. Remember to frequently encourage kitty to indulge himself with his own special suckling/kneading pillow, blanket or toy.

Often a cat's misbehavior is actually reinforced by your unintentional rewards. The cat suddenly runs up, nips you on the ankle and runs off. You scream and chase him. Although you think you are reprimanding the cat, he probably thinks this is a fun game. Cats can also become pests, demanding attention and affection because when they come over to bug you, you give them what they want - food, attention or affection. Read more about how cats learn.

Provide your cat with acceptable ways to expend this energy and act out her predatory behavior. If it's the cat nocturnal activities that annoy you, then train your cat to shift her active phase to earlier in the evening. If you do not provide the cat with some kind of daytime activity, she will spend the day asleep. Instead of letting kitty doze all evening while you are watching television, turn off the tube and play with your cat. If you tire her out early in the evening, chances are more likely that she will sleep all night. If kitty still insists on playing at night, provide her with activities that will not disturb you. Provide your cat with plenty of soft toys.

Start adding 250 mg/day of tryptophan (an amino acid) to his food. Tryptophan is the precursor to serotonin and is a natural way to help mellow out your cat and reduce his hyperactivity and anxiety about the changes in the home. You can buy this in health food stores or online:

http://www.vitaminshoppe.com/store/en/browse/sku_detail.jsp?id=VS-2537

(These are 500mg capsules, so each capsule will last you 2 days) just pull apart the capsule and sprinkle the powder in canned food.

Also she is still young she will probably calm down as she gets older.

Do you have any catnip spray? My 10 month old kitten is hyper too, and sometimes I've played with him for an hour and don't have time for any more play!! When his happens, i spray a toy with catnip and it entertains him for about half an hour without me needed to stop what i'm doing! Give it a try :-)

Typical clinical signs of Hyperthyroidism

Hyperthyroidism is almost exclusively seen in middle- to old-aged cats, and is rarely seen in cats less than seven years of age. Male and female cats are affected with an equal frequency and although no studies have shown any breeds that are particularly prone to developing hyperthyroidism, there is some evidence that it is less common in Siamese cats.

Cats affected with hyperthyroidism usually develop a variety of clinical signs, which are usually quite subtle at first, but then become more severe as the disease progresses. Also, as this disease occurs mostly in older cats, some affected cats will have other diseases that can complicate and even mask some of the clinical signs.

The 'classic' signs of hyperthyroidism are weight loss, usually despite an increased appetite (polyphagia), increased thirst (polydipsia), increased irritability, and restlessness or even hyperactivity. Many affected cats have a rapid heart rate (tachycardia) and develop an unkempt coat. Mild to moderate diarrhoea and/or vomiting is also quite common. Some affected cats will be noticeably intolerant of heat and seek out cooler places to sit, and some (especially advanced cases) may pant when they are stressed. Most hyperthyroid cats will show some degree of polyphagia (excessive appetite) and restlessness, but in some advanced cases there will be generalised weakness, lethargy and loss of appetite and the signs will be less characteristic.

References

http://www.otherhealth.com/archive/index.php/t-721.html
http://perfectpaws.com/spring.html
http://www.fabcats.org/hyperthyroidism.html
http://www.petplace.com/drug-library/amitriptyline-hcl-elavil/page1.aspx