Neurological and psychological disorders are the main complications specifically correlated with an overactive thyroid gland. Our study aimed to assess neurological diseases and behavioral abnormalities of hyperthyroidism. Hyperthyroidism was induced by administering L-thyroxine sodium at a dosage of 240 μg/kg B.W via gastric gavage once daily for 20 days. A comparative analysis was conducted using a dosage of 10 mg/kg B.W. of the commonly used anti-thyroid drug "propylthiouracil" to assess its effects concerning the hyperthyroid rats. A total of twenty-four adult male albino rats were selected and assigned to three groups using a random allocation method as follows: negative control, positive control, and propylthiouracil groups. The findings indicated that the animal model of hyperthyroidism showed a notable rise in the levels of serum Free T3 and T4, alongside a decline in serum TSH level. There were significant alterations in the dopaminergic and cholinergic systems; dopamine level was greatly boosted, accompanied by a substantial decrease in acetylcholine levels. Hyperthyroid rats displayed significantly poorer performance in the Novel recognition memory task, demonstrating the occurrence of memory impairment in the hyperthyroidism state.