Background. Research is needed to evaluate the efficacy of prevention and treatment for post-partum depression.

Method. Subjects were screened with the Edinburgh Post-natal Depression Scale (EPDS) at the obstetric clinic. Mothers at risk (N = 258) (EPDS scores [ges ]9) were randomly assigned to a prevention/treatment group or a control group. The prevention group received one cognitive-behavioural prevention session during hospitalization. At 4 to 6 weeks post-partum, subjects were screened again with the EPDS, after drop-out rates (refusals plus no return of the second EPDS) of 25.4% (33/130) in the intervention group and 10.9% (14/128) in the control group. Mothers with probable depression (EPDS scores [ges ]11) were assessed using the Hamilton Depression Rating Scale (HDRS) and the Beck Depression Inventory (BDI). Mothers with major depression continued in the treatment group (N = 18) or in the control group (N = 30). Treated subjects received a cognitive-behavioural programme of between five and eight weekly home-visits.

Results. Compared with the control group, women in the prevention group had significant reductions in the frequency of probable depression (30.2% v. 48.2%). Recovery rates based on HDRS scores of <7 and BDI scores of <4 were also significantly greater in the treated group than in the control group.

Conclusions. The study suggests that this programme for prevention and treatment of post-partum depression is reasonably well-accepted and efficacious.

In this paper we review studies aiming at elucidation of the mechanisms responsible for anomalously low pressure coefficients of the light emission energy, dEE/dP, observed in quantum structures of InGaN/GaN and GaN/AlGaN. We have established that in hexagonal InGaN/GaN and GaN/AlGaN structures the main mechanism involved is related to the pressure induced increase of the piezoelectric field which determines also the strong red shift of the emission energy with thickness of the quantum well. To reproduce the experimental findings in InGaN/GaN case, it is necessary to take into account the dependence of the piezoelectric constants on the volume-conserving strain. Whereas the experimental results on a decrease of dEE/dP in GaN/AlGaNstructures can be fully accounted for within the linear elasticity theory. In contrast to these findings, dEE/dP magnitude measured in cubic InGaN/GaN quantum structures shows value close to changes of the InGaN bangap with pressure obtained from first principle calculations. The latter result is consistent with the absence of the built-in electric fields in the cubic nitride structures.