Hi.
I too am a depressive, which I have suffred from many years.
Depression is a much misunderstood ailment/condition and there are many different shades, intensities and types of depression.
For myself, it comes allied to anxiety and it took many years with a number of different diagnosis including bipolar disorder, which was ‘downgraded’ to borderline personality disorder. This in turn has, at this time, been re-designated as ‘Anxiety disorder with associated depression’.

Why have I listed these? Well, to illustrate the journey that I believe the Buddhist Dhamma has enabled me to make.
It can often be difficult to separate symptom from cause in mental health and I came to understand, in hindsight, that for a long time my ‘condition’ was in fact just how my mind reacted to the underlying anxiety that I battle with on a daily basis.
Maybe one day this final hurdle will also be left to the past as I deepen my practice.

The one thing that has the most difference is learning to remain in the moment and to experience/observe the rising and passing away of my mind’s thoughts.
when this is truly experienced, there remains no basis for any reaction. The same anxious thoughts appear but more often than not, I now don’t react to these and so my depression is kept at bay.
Now that fear and the dispondancy that would come as a reaction to fear no longer grip me as before, I no longer ‘act out’ in order to try to alter my state of mind. So I no longer have the behaviours that were previously diagnoses as Bipolar or as due to BP Disorder.

So. Thanks to just this one, beautiful, realisation of Siddartha that all things are impermenant, that they simply arise and pass away, I am able to enjoy life so much more.

There is so much in the dhamma, I would suggest that anyone suffering from depression, or any other mental health issue, choose to work with only those parts that they notice help their situation. We have the rest of our lives to study the other parts.
Metta