Thank you so much for this wonderful contribution, Sir. @agmoore
Yes, you are very correct about the side effects of diazepam, one of them is addiction. But then, every drug has side effects, including the commonly used paracetamol.
However, we consider the risk-benefit ratio of a drug. These drugs are prescribed when the benefit of the drug outweighs the risk associated with it. For patients with hyperthyroidism, anxiety will do them more harm than the addiction associated with diazepam. So, diazepam is prescribed, though with caution to minimize the negative effects as much as possible.
Another example here is the cytotoxic drugs (chemotherapy) used for cancer patients. Those drugs have very serious side effects. But the benefit to the cancer patient still outweighs this risk because, without those drugs, the patient may not even live to witness those side effects.
However, science/medicine is still evolving. Research is always ongoing to improve on the existing drugs or invent new ones. I remember the first sets of Antiretroviral therapy (ART) used for HIV patients. They had very serious side effects too. But the newer HIV drugs now are far better tolerated. So, hopefully, someday, we will have a better option than diazepam.
Many thanks, sir.