Spent years, I hoped, taking tablets for severe unease? (9)

'severe unease?' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.

'spent years i hoped taking tablets' is the wordplay.
'spent' indicates anagramming the letters.
'taking' suggests deleting specific letters (take can mean remove or delete).
'tablets' becomes 'EE' (more than one Ecstasy pill).
'years'+'i'+'hoped'='yearsihoped'
'yearsihoped' with 'ee' taken away is 'yarsihopd'.
'yarsihopd' is an anagram of 'DYSPHORIA'.

'for' is the link.

Can you help me to learn more?