  We investigated narrow line Seyfert 1 galaxies (NLS1s) at optical,
mid-infrared (MIR) and X-ray wavelengths, comparing them to the broad line
active galactic nuclei (BLAGNs). We found that black hole mass, coronal line
luminosities, X-ray hardness ratio and X-ray, optical and MIR luminosities are
higher for the BLAGNs than for NLS1s, while policyclic aromatic hydrocarbon
(PAH) contribution and the accretion rates are higher for the NLS1s.
Furthermore, we found some trends among spectral parameters that NLS1s have and
BLAGNs do not have. The evolution of FWHM(H$\beta$) with the luminosities of
MIR and coronal lines, continuum luminosities, PAH contribution, H$\beta$ broad
line luminosity, FWHM[O\,III] and EW(H$\beta$NLR), are important trends found
for NLS1s. That may contribute to the insight that NLS1s are developing AGNs,
growing their black holes, while their luminosities and FWHM(H$\beta$)
consequently grow, and that BLAGNs are mature, larger objects of slower and/or
different evolution. Black hole mass is related to PAH contribution only for
NLS1s, which may suggest that PAHs are more efficiently destroyed in NLS1s.
