I had clinical depression. Because of that, I lost 5 years of my life.
To put things in perspective - I am starting as a Ph.D. student this year, but my undergraduate classmates have already completed Ph.D. plus one postdoc.
If I want to become an academician, how can I recover this lost time?
Is increasing the impact factor a way forward? What else can I do?
You seem to have the assumption that as an academic, you will be evaluated based on your scientific contributions put in perspective with your age, i.e., from birth. This is in many ways inaccurate.
For example, countries and their education systems vary greatly in when people typically start a PhD and how much time they take to complete it. What you may feel is a late time to start a PhD might be considered a very usual time in a country where it is common that some people work in industry for a few years before deciding to start a PhD, or waste years applying for a grant before starting their PhD. Academia varies a lot, so the "norm" is not as clear a concept as you'd think. In my small experience as a young academic, just in my discipline, I've both met people that were 5 years younger than I was when they completed their PhD, and people that were 3 years older.
Apart from the 40 years old age cap for Fields medalists, the only age limits I am aware of (from my small corner of academia) tend to be time limits "from PhD". For example, some grants can only be awarded to people that received their PhD in the last 4 years. Since your five year career gap did not occur after you received your PhD, none of those apply to you. Also, at least some of those grants actually are designed to take into account career gaps, like time taken off of your career for medical reason and maternity/paternity leave, which can sometimes be subtracted from the 4 years time limits.
This will also be true of your scientific contributions. They will mostly be judged not based on your age, but your 'age since PhD'.
So, as someone said in the comments, do not think in terms of age: you are part of the cohort of people starting a PhD this year. Then, general advice on how to succeed in academia applies. In particular, as many PhD students experience some amount of psychological distress during their PhD, keep your mental health a priority, and reach out if the conditions of a successful PhD are not there (this website contains quite a few stories of people that changed advisor or subject).
You can't recover the lost time. It is gone forever. But it doesn't restrict your future. Do what any beginning doctoral student needs to do. Pay attention, work hard, take a lot of notes, talk to a lot of people, especially professors.
Find a good advisor who can give good and timely advice. Work with them to find a good problem to attack. Onward.
Looking back isn't going to get you anywhere.
And if there are lingering effects from the depression, keep in touch with a professional so that it doesn't become an issue again.
Edited to add: When it comes time to evaluate your tenure application you will, perhaps, be a bit older than the average candidate. But you will be judged by people older still and the most influential might be very much older for which your age at that time is completely irrelevant. You will be judged on what you have accomplished, not your age.
Obviously in the immediate term you cannot "make up lost time". All we can do is make the remaining time as good as possible.
On the positive side, you will have far greater self-awareness now. You'll know how your mind works and how not to over-strain it. These are important things over the duration of a doctoral programme.
You will also be aware of the need to balance life and work - however well work may be going or however frustrating it becomes.
What you have learned about life and yourself will be very useful over the next years. Apply it wisely and ignore the follies of your professional contemporaries but experiential juniors. It might be good to link up with some mature doctoral students in your department or around the campus generally (regardless of country of origin) as we all have an emotional connection with our own age group.
Focus on quality of work, not speed or quantity. Try to give a little back to the system you work in, time permitting - and in an even-handed way - to those around you.
In the long term the quality of our remaining life is what determines if our "lost" periods were truly lost or not.
It is very important to get rid of this "catch-up" mindset prior to starting a PhD. If you find it hard to shake off, especially even after some sessions with a therapist, I think it would be wiser not to go into the programme just yet. Maybe a 9-5 RA job for a while or something outside academia.
I say this because there will be younger researchers rushing around and maybe trying to generate a competitive dynamic to assuage their own doubts and anxieties. Sadly, there are always some faculty who cultivate competition between postgrads. You don't want to be part of this madness.
So you need to be clear and strongly firm - on bad days as well as good - on your quality of work and life mindset before taking on any serious research programme commitment. Please discuss all this with your therapist.
Also look your would-be supervisor in the eye as you tell him/her that work - however interesting and rewarding, however important success is for the department's appearance in the eyes of research grant givers - is not all there is to your life. In the situation you are in, a down-to-earth supervisor with an "ordinary" project would be far wiser than a pushy supervisor with an "exciting/topical/heavily-funded" project: you'll have more time for TA work, colleague engagement and learning by doing - all things that are vital for your development and self-confidence.
Here are my advises that could be helpful for you:
I wish a good luck to you "our future Dr."
Publishing high-impact papers may expedite your rise up the academic ladder (then again, it may not, since we live in a strange world and heads of department hold inordinate amounts of unchecked power*); all else being equal, one does better as one's papers are higher-impact. So in that sense, yes, good idea.
What is strange is that you should think that "high impact" is the answer to "making up for lost time" - as if you would not consider high impact as a priority or a smart thing to aim for if you had remained "on schedule" and not lost so much time.
From a strictly logical point of view, your question "is high impact the remedy for lost time?" is on a par with "is doubling my IQ the remedy for lost time?" In both cases the tentative answer is something like: yeah, it probably cannot hurt, but it seems odd to think that this might be the answer to that.
The time people spend post-docking is highly variable, and even among roughly equal quality people in the same field one can get tenure years earlier than the other. So if luck runs your way, you could easily make up the lost time during the post-doc phase. The best you can do in any case is just, merely, your best.
There is one respect in which "high impact" as an aim or priority can be counter-productive. This happens when academics "safe up" results and findings in hopes of all their loose ends somehow aggregating into a Nature/Science/PNAS paper, rather than being published bit by bit in the decent journals on the tiers below. It is unusual and probably counterproductive for a PhD student to develop this particular neurosis, but I thought I should warn you anyway.
*) Yes, you may find yourself out on your ear after publishing in Nature and PNAS, just because your HoD felt belittled.
I think the perspective is different. Do you drive cars? From the way you write it sounds like your car's transmission has been stuck for a while, but it sounds like you've come out of it well strengthened. It's all about soft skills. It's never about dates on resumes but about your ability “someday” when you are pH.D to offer a competitive advantage to those who will read your resume. How many college graduates have skills that don't stand out?
