Academic writing is supposed to be formal, but there can be big differences between different fields of academic writing. A technical field like Computer Science will often focus on being concise and have strict styles for formatting source code. Fields like Psychology will focus a lot more on the methodical parts of for example creating your survey questions.
Therefore the best advice when it comes to writing styles in academic writing is to read much of the literature that is common in your field.
Read about what others have to say about the topics you are interested in and what their sources say. Maybe even ask others in your field you know what they think about a certain paper or writing style of an author. By reading a lot of these papers and articles you will get a feeling for what is acceptable and which parts are important.
Personally, coming from a technical field, I would say that your second sentence sounds a little bit too "sensational". When reading something slowly I always imagine someone saying it out loud to get a feeling for what the effect is supposed to be. While reading your second sentence I felt like someone was trying to underline an important part and slowly building up suspense. That's a nice writing style, which I generally like, for novels, especially mystery novels when a detective is revealing something interesting or important to someone else and thereby to the reader. But for academical writing I prefer simple facts. I am trying to get information as quickly as possible. Building up suspense doesn't help with this. You could simply combine those sentences to something like "The environment had a significant impact on the state of his psychological well-being. It was responsible for his because of ." That would be clear, factual and already include the things that you would have likely written in a third sentence not presented here.