How Can I reduce the vertical line space between titles?

Question

My title in a presentation in Rmarkdown using metropolis, is large like here in the example below, and hence breaks it somewhere, however, the vertical line between lines is large and I need to reduce it using \\ [1pt]. But it does work.

---
author: Yebelay Berelie Berehan
title: \scriptsize
       Randomized controlled trials (RCTs) are generally considered the gold standard \\ [1pt] for estimating causal effects of treatments 

institute: |
        | Email: \textcolor{blue}{[email protected]}
        |
date: \today
output: 
  binb::metropolis:
    citation_package: natbib
    highlight: kate
    includes:
      in_header: header.tex
bibliography: demo.bib
biblio-style: abbrvnat
beameroption: "show notes"
#toc: true
---

Where header.tex is

\titlegraphic{\centering \includegraphics[width=1.5 cm]{logo.png}}
\usepackage{booktabs}
\usepackage[scale=2]{ccicons}
\usepackage{xspace}
\newcommand{\themename}{\textbf{\textsc{metropolis}}\xspace}
\metroset{titleformat frame=smallcaps}