Being addicted to or hooked on something; becoming completely absorbed in an activity or habit.
このゲームはとても面白くて病みつきになった。
This game is so fun that I got hooked on it.
彼はコーヒーの味に病みつきで、毎日いろいろな豆を試している。
He's become obsessed with coffee flavors and tries different beans every day.
安いからといって買いすぎるのは病みつきの兆候だ。
Buying too much just because it's cheap is a sign you're getting addicted.
Falling ill; becoming sick (older or less common usage).
寒さで病みつきになり、二日間寝込んだ。
He fell ill from the cold and was bedridden for two days.
昔は風邪の病みつきが長引くことが多かった。
In the past, colds often developed into prolonged illnesses.
病みつきで欠席が続き、学校を休学した。
He kept missing school because of illness and took a leave of absence.